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预防老年人流感的疫苗

Appendices

Appendix 1. Included studies design

Case‐control study: a retrospective epidemiological study usually used to investigate the association between two variables (e.g. hospitalisation for pneumonia and influenza vaccination). Study participants who have experienced an event (adverse or disease‐related) are compared with participants who have not. Any differences in the presence or absence of hypothesised risk or protective variables are observed.

Cohort study: an epidemiological study where groups of individuals are identified who vary in their exposure to an intervention or hazard, and who are then followed to assess outcomes. Association between exposure and outcome are then estimated. Cohort studies are best performed prospectively, but can also be undertaken retrospectively if suitable data records are available.

Randomised controlled trial: any study on humans in which the individuals (or other experimental units) followed in the study were definitely or possibly assigned prospectively to one of two (or more) alternative forms of health care using random allocation.

Quasi‐randomised clinical trial: any study on humans in which the individuals (or other experimental units) followed in the study were definitely or possibly assigned prospectively to one of two (or more) alternative forms of health care using some quasi‐random method of allocation (such as alternation, date of birth, or case record number).

Appendix 2. MEDLINE (Ovid) and CENTRAL search strategy

1 Influenza Vaccines/
2 Influenza, Human/tm, pc, im, mo, ep [Transmission, Prevention & Control, Immunology, Mortality, Epidemiology]
3 Influenza, Human/
4 exp Influenzavirus A/
5 exp Influenzavirus B/
6 (flu or influenza*).tw.
7 or/3‐6
8 Vaccines/
9 vaccines, attenuated/ or vaccines, inactivated/ or exp vaccines, subunit/ or exp vaccines, synthetic/ or viral vaccines/
10 exp Immunization/
11 (vaccin* or immuni* or inocul*).tw.
12 exp Adjuvants, Immunologic/
13 (vaccin* adj5 adjuvant*).tw.
14 Squalene/
15 (aluminium or squalene or MF59 or virosom*).tw,nm.
16 or/8‐15
17 7 and 16
18 1 or 2 or 17
19 exp Adult/
20 Men/
21 Women/
22 Retirement/
23 ((old* or age*) adj3 (people* or person* or adult* or women* or men* or citizen* or residen*)).tw.
24 (pension* or retire* or adult* or aged or elderly or senior* or geriatric*).tw.
25 long‐term care/ or nursing care/ or palliative care/
26 homes for the aged/ or nursing homes/
27 nursing home*.tw.
28 or/19‐27
29 28 and 18

Appendix 3. Embase (Elsevier) search strategy

26. #23 AND #26
25. #24 OR #25
24. random*:ab,ti OR placebo*:ab,ti OR factorial*:ab,ti OR crossover*:ab,ti OR 'cross‐over':ab,ti OR 'cross over':ab,ti OR assign*:ab,ti OR allocat*:ab,ti OR volunteer*:ab,ti OR ((singl* OR doubl*) NEAR/2 (blind* OR mask*)):ab,ti
23. 'randomized controlled trial'/exp OR 'single blind procedure'/exp OR 'double blind procedure'/exp OR
'crossover procedure'/exp
22. #15 AND #22
21. #16 OR #17 OR #18 OR #19 OR #20
20. 'aged care':ab,ti OR 'nursing home':ab,ti OR 'nursing homes':ab,ti
19. 'nursing home'/exp OR 'hospice'/de OR 'residential home'/de
18. pension*:ab,ti OR retire*:ab,ti OR adult*:ab,ti OR aged:ab,ti OR elderly:ab,ti OR senior*:ab,ti OR geriatric*:ab,ti
17. ((old* OR age*) NEAR/3 (people* OR person* OR adult* OR women OR men OR citizen* OR residen*)):ab,ti
16. 'adult'/de OR 'aged'/exp OR 'pensioner'/exp
15. #1 OR #14
14. #5 AND #13
13. #6 OR #7 OR #8 OR #9 OR #10 OR #11 OR #12
12. aluminium:ab,ti OR squalene:ab,ti OR mf59:ab,ti OR virosom*:ab,ti
11. 'squalene'/de
10. (vaccin* NEAR/5 adjuvant*):ab,ti
9. 'immunological adjuvant'/de
8. vaccin*:ab,ti OR immuni*:ab,ti OR inocul*:ab,ti
7. 'immunization'/de OR 'vaccination'/de OR 'active immunization'/de OR 'immunoprophylaxis'/de OR 'mass
immunization'/de
6. 'vaccine'/de OR 'acellular vaccine'/de OR 'dna vaccine'/de OR 'inactivated vaccine'/de OR 'live vaccine'/de OR 'subunit vaccine'/de OR 'virus vaccine'/de OR 'virosome vaccine'/de OR 'recombinant vaccine'/de
5. #2 OR #3 OR #4
4. flu:ab,ti OR influenza*:ab,ti
3. 'influenza virus a'/exp OR 'influenza virus b'/exp
2. 'influenza'/exp
1. 'influenza vaccine'/de

Appendix 4. Web of Science search strategy

Topic=(influenza or flu or influenzavirus) AND Topic=(vaccine* or immuni* or inocul* or adjuvant* or squalene or aluminium or MF59 or virosom*) AND Topic=(aged or elderly or senior* or geriatric* or retire* or pension* or old* people or old* person* or old* adult* or old* men or old* women or old* citizen* or old* residen* or nursing home*)

Refined by: Topic=(random* or placebo* or rct or single blind* or double blind*)

Timespan = 2006 to 2009.

Appendix 5. CINAHL (EBSCO) search strategy

S1

(MH "Influenza Vaccine")

S2

(MH "Influenza, Human+/TM/PC/IM/MO/EP")

S3

(MH "Influenza, Human") OR (MH "Influenza A H5N1") OR (MH "Influenza, Pandemic (H1N1) 2009") OR (MH "Influenza, Seasonal")

S4

(MH "Influenza A Virus+")

S5

(MH "Influenzavirus B+")

S6

TI ( influenza* or flu ) OR AB ( influenza* or flu )

S7

S3 or S4 or S5 or S6

S8

(MH "Vaccines+")

S9

(MH "Immunization+")

S10

(MH "Immunization Programs")

S11

TI ( vaccin* or immuni* or inocul* ) OR AB ( vaccin* or immuni* or inocul* )

S12

TI ( aluminium or squalene or mf59 or virosom* ) OR AB ( aluminium or squalene or mf59 or virosom* )

S13

S8 or S9 or S10 or S11 or S12

S14

S7 and S13

S15

S1 or S2 or S14

S16

(MH "Aged+")

S17

(MH "Gerontologic Care")

S18

(MH "Nursing Homes") OR (MH "Residential Facilities")

S19

(MH "Nursing Home Patients")

S20

(MH "Long Term Care")

S21

(MH "Adult")

S22

(MH "Men") OR (MH "Aged, Hospitalized") OR (MH "Women")

S23

TI ( pension* or retire* or adult* or aged or elderly or senior* or geriatric* ) OR AB ( pension* or retire* or adult* or aged or elderly or senior* or geriatric* )

S24

TI ( (old* or age*) N3 (people* or person* or adult* or women* or men* or citizen* or residen*) ) OR AB ( (old* or age*) N3 (people* or pension* or adult* or women* or men* or citizen* or residen*) )

S25

TI ( "aged care" or "nursing home" or "nursing homes" ) OR AB ( "aged care" or "nursing home" or "nursing homes" )

S26

S16 or S17 or S18 or S19 or S20 or S21 or S22 or S23 or S24 or S25

S27

S15 and S26

S28

(MH "Clinical Trials+")

S29

PT clinical trial

S30

TI clinic* trial* OR AB clinic* trial*

S31

TI ( (singl* or doubl* or trebl* or tripl*) N1 (blind* or mask*) ) OR AB ( (singl* or doubl* or trebl* or tripl*) N1 (blind* or mask*) )

S32

(MH "Random Assignment")

S33

(MH "Placebos")

S34

(MH "Quantitative Studies")

S35

TI ( random* or placebo* ) OR AB ( random* or placebo* )

S36

S28 or S29 or S30 or S31 or S32 or S33 or S34 or S35

S37

S27 and S36

Appendix 6. LILACS (Bireme) search strategy

(mh:"Influenza Vaccines" OR "Vacunas contra la Influenza" OR "Vacinas contra Influenza" OR "Vacunas contra Gripe" OR "Vacunas Antigripales" OR "Vacinas contra Gripe" OR "Vacinas Antigripais" OR ((mh:"Influenza,Human" OR "Gripe Humana" OR "Influenza Humana" OR grippe OR influenza* OR flu OR gripe OR "Influenza en Humanos" OR "Influenza em Humanos") AND (mh:"vaccines" OR vacunas OR vacinas OR mh:d20.215.894* OR mh:"Immunization" OR inmunización OR imunização OR vaccin* OR immuni* OR inocul*))) AND (mh:"Aged" OR anciano* OR idoso* OR elderly OR mh:m01.060.116.100* OR mh:"adult" OR adulto OR idosa OR mh:"Retirement" OR retire* OR jubilación OR aposentadoria OR jubilado OR aposentado OR geriatric* OR geriátrica OR geriátricos OR pension* OR "old age" OR mh:"Homes for the Aged" OR "Hogares para Ancianos" OR "Instituição de Longa Permanência para Idosos" OR "Asilos de Ancianos" OR "Casas para Ancianos" OR "Instituição Asilar" OR "Asilos para Idosos" OR ancianatos OR mh:"nursing homes" OR "Casas de Salud" OR "Casas de Saúde") AND (instance:"regional") AND ( db:("LILACS") AND type_of_study:("clinical_trials"))

Appendix 7. Trials registers search strategies

WHO ICTRP (http://www.who.int/ictrp/en/)

vaccine* AND influenza

immuni* AND influenza

inocul* AND influenza

vaccine* AND flu

immuni* AND flu

inocul* AND flu

ClinicalTrials.gov (www.clinicaltrials.gov)

(vaccine OR vaccines OR vaccinate OR vaccination OR vaccinated OR vaccinating OR immunise OR immunised OR immunising OR immunisation OR immunize OR immunized OR immunizing OR immunization) AND (influenza OR influenza OR flu)

(inoculate OR inoculated OR inoculating OR inoculation) AND (influenza OR influenza OR flu)

Appendix 8. Previous search details

For the 2009 update we searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register, the Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effects (The Cochrane Library 2009, Issue 4); MEDLINE (January 1966 to October Week 1 2009); EMBASE (1974 to October 2009) and Web of Science (1974 to October 2009).

We used the search in Appendix 2 to search MEDLINE and CENTRAL. The search terms were combined with the Cochrane Highly Sensitive Search Strategy for identifying RCTs in MEDLINE: sensitivity‐ and precision‐maximising version (2008) revision; Ovid format (Lefebvre 2011). This search was adapted for Embase (Appendix 3) and Web of Science (Appendix 4). The search terms were also combined with the SIGN (SIGN 2009) search strategy for identifying observational studies (see Appendix 11) and MEDLINE, Embase and Web of Science were searched for observational studies.

There were no language or publication restrictions. The search of CENTRAL included trial reports identified by the systematic search by hand of the journal Vaccine.

In order to identify additional published and unpublished studies:

  1. We used the Science Citation Index to identify articles that cite the relevant studies;

  2. We keyed the relevant studies into PubMed and used the Related Articles feature;

  3. We searched the bibliographies of all relevant articles obtained, any published reviews and proceedings from relevant conferences for additional studies;

  4. We explored Internet sources: NHS National Research Register (www.update-software.com/national/), the metaRegister of Clinical Trials (www.controlled-trials.com/) and the digital dissertations web site (wwwlib.umi.com/dissertations);

  5. We searched the Vaccine Adverse Event Reporting System web site (www.vaers.org); and

  6. We contacted vaccine manufacturers listed at the WHO web site.

For the 2006 update we searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register, the Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effectiveness (The Cochrane Library 2006, issue 1); MEDLINE (January 1966 to March Week 3 2006); EMBASE (Dialog 1974 to 1979; SilverPlatter 1980 to December 2005); Biological Abstracts (SilverPlatter 1969 to December 2004); and Science Citation Index (Web of Science 1974 to December 2004). The following MEDLINE search terms were combined with a methodological search filter for high sensitivity in identifying randomised controlled trials in MEDLINE (Dickersin 1994) and adapted to search the other above mentioned electronic databases.

MEDLINE (Ovid) (2006 update)

1 exp Influenza Vaccines/
2 Influenza, Human/ep [Epidemiology]
3 Influenza, Human/im [Immunology]
4 Influenza, Human/mo [Mortality]
5 Influenza, Human/pc [Prevention & Control]
6 Influenza, Human/tm [Transmission]
7 influenza vaccin$.ti,ab.
8 (influenza or flu).ti,ab.
9 (vaccin$ or immuni$ or inocul$ or efficacy or effectiveness).ti,ab.
10 and/8‐9
11 or/1‐7,10
12 RANDOMIZED CONTROLLED TRIAL.pt.
13 CONTROLLED CLINICAL TRIAL.pt.
14 RANDOMIZED CONTROLLED TRIALS.sh.
15 RANDOM ALLOCATION.sh.
16 DOUBLE BLIND METHOD.sh.
17 SINGLE‐BLIND METHOD.sh.
18 or/12‐17
19 Animals/
20 Humans/
21 19 not 20
22 18 not 21
23 CLINICAL TRIAL.pt.
24 exp Clinical Trials/
25 (clin$ adj25 trial$).ti,ab.
26 ((singl$ or doubl$ or trebl$ or tripl$) adj25 (blind$ or mask$)).ti,ab.
27 PLACEBOS.sh.
28 placebo$.ti,ab.
29 random$.ti,ab.
30 or/23‐29
31 30 not 21
32 exp Research Design/
33 exp Comparative Study/
34 exp Evaluation Studies/
35 exp Follow‐Up Studies/
36 exp Prospective Studies/
37 prospectiv$.ti,ab.
38 volunteer$.ti,ab.
39 exp Case‐Control Studies/
40 (cases and controls).ti,ab.
41 case control stud$.ti,ab.
42 exp Cohort Studies/
43 cohort stud$.ti,ab.
44 observational.ti,ab.
45 or/32‐44
46 45 not 21
47 or/22,31,46
48 11 and 47

Appendix 9. Data extraction form

PART 1

Background Information and Description of study
Reviewer:
Study unique identifier:
Published: Y/N
Journal: (if applicable)
Year of publication:
Period study conducted:
Abstract/full paper:
Country or countries of study:
Number of studies included in this paper:
Funding source (delete non applicable items):
Government, Pharmaceutical, Private, Unfunded, Unclear:
Paper/abstract numbers of other studies with which these data are linked:
Reviewer's assessment of study design (delete non applicable items):

Study Category ‐ Study Design
Experimental ‐ RCT/CCT; HCT ; X cross‐over RCT
Non‐randomised analytical (specifically designed to assess association) ‐ Prospective/
Retrospective Cohort ; Case Control ; X sectional
Non‐randomised comparative (not specifically designed to assess association) ‐ Case X Over/Time series ;
Ecological study; Indirect comparison (before and after)
Non‐comparative EXCLUDE

Does the study present data distributed by age group/occupation/health status? (Yes/No)
Sub group distribution:
Age group Y/N
Occupation Y/N
Health status Y/N
Gender Y/N
Risk group Y/N

Description of study
Methods
Participants
Interventions/exposure
Outcomes
Notes

PART 2a

Methodological Quality Assessment RCT and CCT only
Randomisation:
A = individual participants allocated to vaccine or control group.
B = groups of participants allocated to vaccine or control group.

Generation of the allocation sequence:
A = adequate, e.g. table of random numbers or computer‐generated random numbers.
B = inadequate, e.g. alternation, date of birth, day of the week, or case record number.
C = not described.

Allocation concealment:
A = adequate, e.g. numbered or coded identical containers administered sequentially, on‐site computer system that can only be accessed after entering the characteristics of an enrolled participant, or serially numbered, opaque, sealed envelopes.
B = possibly adequate, e.g. sealed envelopes that are not sequentially numbered or opaque.
C = inadequate, e.g. open table of random numbers.
D = not described.

Blinding:
A = adequate double‐blinding, e.g. placebo vaccine.
B = single‐blind, i.e. blinded outcome assessment.
C = no blinding.

Follow up:

Average duration of follow up and number of losses to follow up.

PART 2b

Description of interventions and outcomes RCT and CCT only
Vaccines used
Vaccines and composition | Product and manufacturer | Schedule & dosage and status | Route of administration
Arm 1
Arm 2
Arm 3
Arm 4
Placebo
Rule: index vaccine goes in the Arm 1 line, placebo in the last line

Status: primary, secondary or tertiary immunisation.

Vaccine Batch Numbers

Details of Participants
Enrolled | Missing | Reasons | Inclusion in analysis | Notes
Active arm 1
Active arm 2
Active arm 3
Active arm 4
Controls

Outcomes List ‐ Efficacy and Effectiveness
Outcome | How defined | Description/Follow up/Notes

Outcomes List ‐ Safety
Outcome | How defined | Description/Follow up/Notes

Investigators to be contacted for more information? Yes/No

Contact details (principal investigator, fill in only if further contact is necessary):

PART 2c

Data extraction and manipulation (to be used for dichotomous or continuous outcomes) RCT and CCT only
Comparison
Outcomes | n/N Index Arm | n/N Comparator
Outcomes | n/N Index Arm | n/N Comparator
Outcomes | n/N Index Arm | n/N Comparator

Notes (for statistical use only)

PART 3a

Methodological Quality Assessment. Non‐randomised studies only

Newcastle ‐ Ottawa quality assessment scale (case‐control and cohort studies ; see Appendix 10)

PART 3b

Description of interventions and outcomes. Non‐randomised longitudinal studies only
Vaccines used
Vaccines and composition | Product and manufacturer | Schedule & dosage and status | Route of administration
Group 1
Group 2
Group 3
Group 4
Comparator

Rule: index vaccine goes in the Group 1 line, placebo in the last line

Vaccine Batch Numbers

Details of Participants
Enrolled | Missing | Reasons | Inclusion in analysis | Notes
Group 1
Group 2
Group 3
Group 4
Comparator

Outcomes List ‐ Effectiveness
Outcome | How defined (including length of follow up) | Description/Follow up/Notes

Outcomes List ‐ Safety
Outcome | How defined (including length of follow up) | Description/Follow up/Notes

Investigators to be contacted for more information? Yes/No

Contact details (principal investigator, fill in only if further contact is necessary):

PART 3c

Data extraction and manipulation (to be used for dichotomous outcomes). Non‐randomised longitudinal studies only

Comparison
Outcomes | n/N Index Group | n/N Comparator

Notes (for statistical use only)

PART 3d

Description of studies. Case‐control studies only

Event 1
How defined | Enrolled | Missing | Reasons | Inclusion in analysis
Cases n =
Controls n =

Exposure
How defined | How ascertained | Notes
Vaccine Exposure 1
Vaccine Exposure 2

Event 2
How defined | Enrolled | Missing | Reasons | Inclusion in analysis
Cases n =
Controls n =

Exposure
How defined | How ascertained | Notes
Vaccine Exposure 1
Vaccine Exposure 2

Notes (for statistical use only)

Part 3e

Data extraction and manipulation. Case‐control studies only

Status | Numerator | Denominator
Cases
Control

Notes (for statistical use only)

Appendix 10. Methodological quality of non‐randomised studies

Newcastle‐Ottawa Quality Assessment Scale

Case‐control studies
Selection

  1. Is the case definition adequate?

    1. yes, with independent validation

    2. yes, e.g. record linkage or based on self reports

    3. no description

  2. Representation of the cases

    1. consecutive or obviously representative series of cases

    2. potential for selection biases or not stated

  3. Selection of controls

    1. community controls

    2. hospital controls

    3. no description

  4. Definition of controls

    1. no history of disease (endpoint)

    2. no description of source

Comparability

  1. Comparability of cases and controls on the basis of the design or analysis

    1. study controls for _______________ (select the most important factor)

    2. study controls for any additional factor (this criteria could be modified to indicate specific control for a second important factor)

Exposure

  1. Ascertainment of exposure

    1. secure record (e.g. surgical records)

    2. structured interview where blind to case/control status

    3. interview not blinded to case/control status

    4. written self report or medical record only

    5. no description

  2. Same method of ascertainment for cases and controls

    1. yes

    2. no

  3. Non‐response rate

    1. same rate for both groups

    2. non‐respondents described

    3. rate different and no designation

Newcastle‐Ottawa Quality Assessment Scale

Cohort studies

Note: A study can be awarded a maximum of one star for each numbered item within the 'Selection' and 'Outcome' categories. A maximum of two stars can be given for 'Comparability'.

Selection

  1. Representation of the exposed cohort

    1. truly representative of the average _______________ (describe) in the community

    2. somewhat representative of the average ______________ in the community

    3. selected group of users (e.g. nurses, volunteers)

    4. no description of the derivation of the cohort

  2. Selection of the non‐exposed cohort

    1. drawn from the same community as the exposed cohort

    2. drawn from a different source

    3. no description of the derivation of the non‐exposed cohort

  3. Ascertainment of exposure

    1. secure record (e.g. surgical records)

    2. structured interview

    3. written self report

    4. no description

  4. Demonstration that outcome of interest was not present at start of study

    1. yes

    2. no

Comparability

  1. Comparability of cohorts on the basis of the design or analysis

    1. study controls for _____________ (select the most important factor)

    2. study controls for any additional factor* (this criteria could be modified to indicate specific control for a second important factor)

Outcome

  1. Assessment of outcome

    1. independent blind assessment

    2. record linkage

    3. self report

    4. no description

  2. Was follow‐up long enough for outcomes to occur?

    1. yes (select an adequate follow‐up period for outcome of interest)

    2. no

  3. Adequacy of follow‐up of cohorts

    1. complete follow up ‐ all participants accounted for

    2. participants lost to follow‐up unlikely to introduce bias ‐ small number lost ‐ > ____ % (select an adequate %) follow‐up, or description provided of those lost*

    3. follow‐up rate < ____% (select an adequate %) and no description of those lost

    4. no statement

Appendix 11. SIGN filter for observational studies

SIGN Scottish Intercollegiate Guidelines Network [Internet]. Edinburgh: c2001‐2009; [Last modified 03 August 2009; accessed 02 October 2009]. Available from www.sign.ac.uk/methodology/filters.html on 02 October 2009 (SIGN 2009)

The Observational Studies search filter used by SIGN has been developed in‐house to retrieve studies most likely to meet SIGN's methodological criteria.

MEDLINE

1

Epidemiologic studies/

2

Exp case control studies/

3

Exp cohort studies/

4

Case control.tw.

5

(cohort adj (study or studies)).tw.

6

Cohort analy$.tw.

7

(Follow up adj (study or studies)).tw.

8

(observational adj (study or studies)).tw.

9

Longitudinal.tw.

10

Retrospective.tw.

11

Cross sectional.tw.

12

Cross‐sectional studies/

13

Or/1‐12

EMBASE

1

Clinical study/

2

Case control study

3

Family study/

4

Longitudinal study/

5

Retrospective study/

6

Prospective study/

7

Randomised controlled trials/

8

6 not 7

9

Cohort analysis/

10

(Cohort adj (study or studies)).mp.

11

(Case control adj (study or studies)).tw.

12

(follow up adj (study or studies)).tw.

13

(observational adj (study or studies)).tw.

14

(epidemiologic$ adj (study or studies)).tw.

15

(cross sectional adj (study or studies)).tw.

16

Or/1‐5,8‐15

Study flow. We identified no new randomised controlled trials for the 2016 update and stabilisation.

Figuras y tablas -
Figure 1

Study flow. We identified no new randomised controlled trials for the 2016 update and stabilisation.

Relationship between vaccination rate and attack rate

Figuras y tablas -
Figure 2

Relationship between vaccination rate and attack rate

Comparison 1: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine, Outcome 1: Influenza

Figuras y tablas -
Analysis 1.1

Comparison 1: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine, Outcome 1: Influenza

Comparison 1: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine, Outcome 2: Influenza‐like illness

Figuras y tablas -
Analysis 1.2

Comparison 1: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine, Outcome 2: Influenza‐like illness

Comparison 1: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine, Outcome 3: Pneumonia

Figuras y tablas -
Analysis 1.3

Comparison 1: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine, Outcome 3: Pneumonia

Comparison 1: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine, Outcome 4: All deaths

Figuras y tablas -
Analysis 1.4

Comparison 1: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine, Outcome 4: All deaths

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 1: General malaise

Figuras y tablas -
Analysis 2.1

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 1: General malaise

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 2: Nausea

Figuras y tablas -
Analysis 2.2

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 2: Nausea

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 3: Upper respiratory tract symptoms

Figuras y tablas -
Analysis 2.3

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 3: Upper respiratory tract symptoms

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 4: Headache

Figuras y tablas -
Analysis 2.4

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 4: Headache

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 5: Fever

Figuras y tablas -
Analysis 2.5

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 5: Fever

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 6: Local tenderness/sore arm

Figuras y tablas -
Analysis 2.6

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 6: Local tenderness/sore arm

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 7: Swelling ‐ erythema ‐ induration

Figuras y tablas -
Analysis 2.7

Comparison 2: Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events, Outcome 7: Swelling ‐ erythema ‐ induration

Comparison 3: Influenza vaccines versus placebo: randomised controlled trials ‐ inactivated aerosol vaccine, Outcome 1: Influenza

Figuras y tablas -
Analysis 3.1

Comparison 3: Influenza vaccines versus placebo: randomised controlled trials ‐ inactivated aerosol vaccine, Outcome 1: Influenza

Comparison 3: Influenza vaccines versus placebo: randomised controlled trials ‐ inactivated aerosol vaccine, Outcome 2: Influenza‐like illness

Figuras y tablas -
Analysis 3.2

Comparison 3: Influenza vaccines versus placebo: randomised controlled trials ‐ inactivated aerosol vaccine, Outcome 2: Influenza‐like illness

Comparison 4: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine, Outcome 1: Influenza

Figuras y tablas -
Analysis 4.1

Comparison 4: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine, Outcome 1: Influenza

Comparison 5: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events, Outcome 1: General malaise

Figuras y tablas -
Analysis 5.1

Comparison 5: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events, Outcome 1: General malaise

Comparison 5: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events, Outcome 2: Fever

Figuras y tablas -
Analysis 5.2

Comparison 5: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events, Outcome 2: Fever

Comparison 5: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events, Outcome 3: Upper respiratory tract symptoms

Figuras y tablas -
Analysis 5.3

Comparison 5: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events, Outcome 3: Upper respiratory tract symptoms

Comparison 5: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events, Outcome 4: Lower respiratory tract symptoms

Figuras y tablas -
Analysis 5.4

Comparison 5: Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events, Outcome 4: Lower respiratory tract symptoms

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 1: Influenza

Figuras y tablas -
Analysis 6.1

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 1: Influenza

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 2: Influenza‐like illness

Figuras y tablas -
Analysis 6.2

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 2: Influenza‐like illness

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 3: Pneumonia

Figuras y tablas -
Analysis 6.3

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 3: Pneumonia

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 4: Hospitalisation for influenza‐like illness or pneumonia

Figuras y tablas -
Analysis 6.4

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 4: Hospitalisation for influenza‐like illness or pneumonia

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 5: Deaths from flu or pneumonia

Figuras y tablas -
Analysis 6.5

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 5: Deaths from flu or pneumonia

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 6: All deaths

Figuras y tablas -
Analysis 6.6

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 6: All deaths

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 7: Influenza cases (clinically defined without clear definition)

Figuras y tablas -
Analysis 6.7

Comparison 6: Influenza vaccines versus no vaccination: cohort studies in nursing homes, Outcome 7: Influenza cases (clinically defined without clear definition)

Comparison 7: Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in nursing homes, Outcome 1: Influenza‐like illness

Figuras y tablas -
Analysis 7.1

Comparison 7: Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in nursing homes, Outcome 1: Influenza‐like illness

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 1: Influenza

Figuras y tablas -
Analysis 8.1

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 1: Influenza

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 2: Influenza‐like illness

Figuras y tablas -
Analysis 8.2

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 2: Influenza‐like illness

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 3: Pneumonia

Figuras y tablas -
Analysis 8.3

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 3: Pneumonia

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 4: Hospitalisation for flu or pneumonia

Figuras y tablas -
Analysis 8.4

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 4: Hospitalisation for flu or pneumonia

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 5: Hospitalisation for any respiratory disease

Figuras y tablas -
Analysis 8.5

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 5: Hospitalisation for any respiratory disease

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 6: Deaths from flu or pneumonia

Figuras y tablas -
Analysis 8.6

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 6: Deaths from flu or pneumonia

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 7: Deaths from respiratory disease

Figuras y tablas -
Analysis 8.7

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 7: Deaths from respiratory disease

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 8: All deaths

Figuras y tablas -
Analysis 8.8

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 8: All deaths

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 9: Hospitalisation for heart disease

Figuras y tablas -
Analysis 8.9

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 9: Hospitalisation for heart disease

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 10: Combined outcome: all deaths or severe respiratory illness

Figuras y tablas -
Analysis 8.10

Comparison 8: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 10: Combined outcome: all deaths or severe respiratory illness

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 1: Hospitalisation for influenza or pneumonia

Figuras y tablas -
Analysis 9.1

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 1: Hospitalisation for influenza or pneumonia

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 2: Hospitalisation for any respiratory disease

Figuras y tablas -
Analysis 9.2

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 2: Hospitalisation for any respiratory disease

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 3: Hospitalisation for heart disease

Figuras y tablas -
Analysis 9.3

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 3: Hospitalisation for heart disease

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 4: All deaths

Figuras y tablas -
Analysis 9.4

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 4: All deaths

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 5: Combined outcome: all deaths or severe respiratory illness

Figuras y tablas -
Analysis 9.5

Comparison 9: Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates, Outcome 5: Combined outcome: all deaths or severe respiratory illness

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 1: Influenza

Figuras y tablas -
Analysis 10.1

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 1: Influenza

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 2: Pneumonia

Figuras y tablas -
Analysis 10.2

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 2: Pneumonia

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 3: Hospitalisation for influenza or pneumonia

Figuras y tablas -
Analysis 10.3

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 3: Hospitalisation for influenza or pneumonia

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 4: Hospitalisation for any respiratory disease

Figuras y tablas -
Analysis 10.4

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 4: Hospitalisation for any respiratory disease

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 5: Deaths from respiratory disease

Figuras y tablas -
Analysis 10.5

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 5: Deaths from respiratory disease

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 6: All deaths

Figuras y tablas -
Analysis 10.6

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 6: All deaths

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 7: Hospitalisation for heart disease

Figuras y tablas -
Analysis 10.7

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 7: Hospitalisation for heart disease

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 8: Combined outcome: all deaths or severe respiratory illness

Figuras y tablas -
Analysis 10.8

Comparison 10: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups, Outcome 8: Combined outcome: all deaths or severe respiratory illness

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 1: Influenza

Figuras y tablas -
Analysis 11.1

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 1: Influenza

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 2: Pneumonia

Figuras y tablas -
Analysis 11.2

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 2: Pneumonia

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 3: Hospitalisation for influenza or pneumonia

Figuras y tablas -
Analysis 11.3

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 3: Hospitalisation for influenza or pneumonia

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 4: Hospitalisation for any respiratory disease

Figuras y tablas -
Analysis 11.4

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 4: Hospitalisation for any respiratory disease

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 5: Deaths from respiratory disease

Figuras y tablas -
Analysis 11.5

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 5: Deaths from respiratory disease

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 6: All deaths

Figuras y tablas -
Analysis 11.6

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 6: All deaths

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 7: Hospitalisation for heart disease

Figuras y tablas -
Analysis 11.7

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 7: Hospitalisation for heart disease

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 8: Combined outcome: all deaths or severe respiratory illness

Figuras y tablas -
Analysis 11.8

Comparison 11: Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups, Outcome 8: Combined outcome: all deaths or severe respiratory illness

Comparison 12: Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 1: Influenza‐like illness

Figuras y tablas -
Analysis 12.1

Comparison 12: Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 1: Influenza‐like illness

Comparison 12: Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 2: Hospitalisation for influenza or pneumonia or respiratory disease

Figuras y tablas -
Analysis 12.2

Comparison 12: Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 2: Hospitalisation for influenza or pneumonia or respiratory disease

Comparison 12: Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 3: Deaths from influenza or pneumonia

Figuras y tablas -
Analysis 12.3

Comparison 12: Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 3: Deaths from influenza or pneumonia

Comparison 12: Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 4: All deaths

Figuras y tablas -
Analysis 12.4

Comparison 12: Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers, Outcome 4: All deaths

Comparison 13: Influenza vaccines with adjuvant versus no vaccination: cohort studies in community‐dwellers, Outcome 1: Influenza‐like illness

Figuras y tablas -
Analysis 13.1

Comparison 13: Influenza vaccines with adjuvant versus no vaccination: cohort studies in community‐dwellers, Outcome 1: Influenza‐like illness

Comparison 13: Influenza vaccines with adjuvant versus no vaccination: cohort studies in community‐dwellers, Outcome 2: Hospitalisation for influenza or pneumonia or respiratory disease

Figuras y tablas -
Analysis 13.2

Comparison 13: Influenza vaccines with adjuvant versus no vaccination: cohort studies in community‐dwellers, Outcome 2: Hospitalisation for influenza or pneumonia or respiratory disease

Comparison 13: Influenza vaccines with adjuvant versus no vaccination: cohort studies in community‐dwellers, Outcome 3: All deaths

Figuras y tablas -
Analysis 13.3

Comparison 13: Influenza vaccines with adjuvant versus no vaccination: cohort studies in community‐dwellers, Outcome 3: All deaths

Comparison 14: Influenza vaccines versus no vaccination: case‐control studies in community, Outcome 1: Hospitalisations for influenza or pneumonia

Figuras y tablas -
Analysis 14.1

Comparison 14: Influenza vaccines versus no vaccination: case‐control studies in community, Outcome 1: Hospitalisations for influenza or pneumonia

Comparison 14: Influenza vaccines versus no vaccination: case‐control studies in community, Outcome 2: Hospitalisations for any respiratory disease

Figuras y tablas -
Analysis 14.2

Comparison 14: Influenza vaccines versus no vaccination: case‐control studies in community, Outcome 2: Hospitalisations for any respiratory disease

Comparison 14: Influenza vaccines versus no vaccination: case‐control studies in community, Outcome 3: Deaths from influenza or pneumonia

Figuras y tablas -
Analysis 14.3

Comparison 14: Influenza vaccines versus no vaccination: case‐control studies in community, Outcome 3: Deaths from influenza or pneumonia

Comparison 14: Influenza vaccines versus no vaccination: case‐control studies in community, Outcome 4: Pneumonia (no better defined)

Figuras y tablas -
Analysis 14.4

Comparison 14: Influenza vaccines versus no vaccination: case‐control studies in community, Outcome 4: Pneumonia (no better defined)

Comparison 15: Influenza vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates, Outcome 1: Hospitalisations for influenza or pneumonia

Figuras y tablas -
Analysis 15.1

Comparison 15: Influenza vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates, Outcome 1: Hospitalisations for influenza or pneumonia

Comparison 15: Influenza vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates, Outcome 2: Hospitalisations for any respiratory disease

Figuras y tablas -
Analysis 15.2

Comparison 15: Influenza vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates, Outcome 2: Hospitalisations for any respiratory disease

Comparison 15: Influenza vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates, Outcome 3: Deaths from pneumonia or influenza

Figuras y tablas -
Analysis 15.3

Comparison 15: Influenza vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates, Outcome 3: Deaths from pneumonia or influenza

Comparison 16: Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in community, Outcome 1: Hospitalisations for influenza or pneumonia

Figuras y tablas -
Analysis 16.1

Comparison 16: Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in community, Outcome 1: Hospitalisations for influenza or pneumonia

Comparison 17: Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates, Outcome 1: Hospitalisations for influenza or pneumonia

Figuras y tablas -
Analysis 17.1

Comparison 17: Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates, Outcome 1: Hospitalisations for influenza or pneumonia

Comparison 18: Sensitivity analysis: comparison 01: subgroup analysis by study quality, Outcome 1: Influenza‐like illness

Figuras y tablas -
Analysis 18.1

Comparison 18: Sensitivity analysis: comparison 01: subgroup analysis by study quality, Outcome 1: Influenza‐like illness

Summary of findings 1. Influenza vaccine compared to placebo for preventing influenza in the elderly

Influenza vaccine compared to placebo for preventing influenza in the elderly

Patient or population: people aged over 65 years
Setting: community and residential care institutions in the USA and Europe during influenza seasons between 1965 and 2000
Intervention: influenza vaccine
Comparison: placebo

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

№ of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Risk with placebo

Risk with influenza vaccine

Influenza assessed with: laboratory confirmation

Follow‐up was conducted over an influenza season.

Study population1

RR 0.42
(0.27 to 0.66)

2217
(3 RCTs)

⊕⊕⊝⊝
LOW 2 3

57 per 1000

24 per 1000
(15 to 38)

Influenza‐like illness
assessed with: subjective report

Follow‐up was conducted over an influenza season.

Study population1

RR 0.59
(0.47 to 0.73)

6894
(4 RCTs)

⊕⊕⊕⊝
MODERATE 2

59 per 1000

35 per 1000
(28 to 43)

Pneumonia

Follow‐up was conducted over an influenza season.

No events occurred in 1 study of 699 people.

699
(1 RCT)

⊕⊝⊝⊝
VERY LOW 4 5

Hospitalisations ‐ not reported

All deaths

Follow‐up was conducted over an influenza season.

Study population1

RR 1.02
(0.11 to 9.72)

699
(1 RCT)

⊕⊝⊝⊝
VERY LOW 4 5

6 per 1000

6 per 1000
(1 to 55)

Fever

Follow‐up was conducted over an influenza season.

Study population1

RR 1.57
(0.92 to 2.71)

2519
(3 RCTs)

⊕⊕⊕⊝
MODERATE 6

16 per 1000

25 per 1000
(15 to 43)

Nausea

Follow‐up was conducted over an influenza season.

Study population1

RR 1.75
(0.74 to 4.12)

672
(1 RCT)

⊕⊕⊝⊝
LOW 6 7

24 per 1000

42 per 1000
(18 to 98)

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: confidence interval; RCT: randomised controlled trial; RR: risk ratio

GRADE Working Group grades of evidence
High quality: We are very confident that the true effect lies close to that of the estimate of the effect.
Moderate quality: We are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low quality: Our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low quality: We have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

1Control group risk taken as aggregate of the study control group risks.
2Downgraded one level due to serious risk of bias. Most of the evidence summarised in the meta‐analysis comes from studies with high or unclear risk of bias for more than one 'Risk of bias' domain.
3Downgraded due to indirectness. Uncertainty over the definition, testing, and surveillance of influenza in older trials.
4Downgraded two levels due to very serious imprecision. No events occurred in one study of nearly 700 people. The study was likely underpowered to detect effects on either pneumonia or mortality.
5Downgraded one level due to serious risk of bias. One study contributing data to this outcome had high risk of selection bias.
6Downgraded one level due to serious imprecision. Confidence intervals for nausea and fever were wide and include reduction and increase in risk of adverse events.
7Downgraded one level due to serious risk of bias. One study contributing data to this outcome had unclear risk of selection bias.

Figuras y tablas -
Summary of findings 1. Influenza vaccine compared to placebo for preventing influenza in the elderly
Table 1. Studies included in the various versions of this review and their impact on our conclusions

Review version (searches date)

Number of included trials (RCTs/CCTs)

Number of included observational studies

Estimates of effect (RCTs/CCTs only)

Conclusions (1 to 2 lines from abstract)

Version 1

(24 May 2006)

9

621

Influenza‐like illness

LAIV = no data

TIV = 41% (95% CI 27% to 53%)

IAV = n.s.

Influenza

LAIV = n.s.

TIV = 58% (95% CI 34% to 73%)

IAV = n.s.

In long‐term care facilities, where vaccination is most effective against complications, the aims of the vaccination campaign are fulfilled, at least in part. However, according to reliable evidence the usefulness of vaccines in the community is modest.

The apparent high effectiveness of the vaccines in preventing death from all causes may reflect a baseline imbalance in health status and other systematic differences in the 2 groups of participants.

Version 2

(20 January 2010)

9

662

Influenza‐like illness

LAIV = no data

TIV = 41% (95% CI 27% to 53%)

IAV = n.s.

Influenza

LAIV = n.s.

TIV = 58% (95% CI 34% to 73%)

IAV = n.s.

The available evidence is of poor quality and provides no guidance regarding the safety, efficacy, or effectiveness of influenza vaccines for people aged 65 years or older. To resolve the uncertainty, an adequately powered publicly‐funded randomised, placebo‐controlled trial run over several seasons should be undertaken.

1These include 49 cohort studies for efficacy/effectiveness (79 data sets); 10 case‐control studies for efficacy/effectiveness (12 data sets); 3 studies (cohorts) for Guillain‐Barré syndrome.
2For this update, two cohort studies and two case‐control studies were added to the review (all assessing efficacy/effectiveness).

Key: CCT = controlled clinical trial; CI = confidence interval; IAV = inactivated aerosol vaccines; LAIV = live attenuated vaccines; n.s. = not significant; RCT = randomised controlled trial; TIV = trivalent inactivated vaccines

Figuras y tablas -
Table 1. Studies included in the various versions of this review and their impact on our conclusions
Table 2. Guillain‐Barré syndrome

Study

Influenza season

Vaccine

Population

Age

RR (95% CI)

Schonberger 1979

1976 to 1977

A/New Jersey/76 or A/New Jersey/76 and A/Victoria/75 swine vaccine

All the USA population

> 64 years

5.2 (3.9 to 7.0)

Kaplan 1982

1979 to 1980

Inactivated trivalent

All the USA population

> 18 years

0.6 (0.45 to 1.32)

Kaplan 1982

1980 to 1981

Inactivated trivalent

All the USA population

> 18 years

1.4 (0.80 to 1.76)

Lasky 1998

1992 to 1994

Inactivated trivalent

21 million

> 64 years

1.5 (0.7 to 3.3)

Key: CI = confidence interval; RR = risk ratio

Figuras y tablas -
Table 2. Guillain‐Barré syndrome
Comparison 1. Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1.1 Influenza Show forest plot

3

2217

Risk Ratio (M‐H, Random, 95% CI)

0.42 [0.27, 0.66]

1.1.1 Outbreak ‐ vaccine matching ‐ community ‐ healthy and ill

1

1838

Risk Ratio (M‐H, Random, 95% CI)

0.41 [0.23, 0.74]

1.1.2 Outbreak ‐ vaccine matching ‐ psychiatric hospital

1

177

Risk Ratio (M‐H, Random, 95% CI)

0.35 [0.12, 1.06]

1.1.3 No outbreak ‐ vaccine matching ‐ nursing home ‐ healthy and ill

1

202

Risk Ratio (M‐H, Random, 95% CI)

0.50 [0.20, 1.25]

1.2 Influenza‐like illness Show forest plot

4

6894

Risk Ratio (M‐H, Random, 95% CI)

0.59 [0.47, 0.73]

1.2.1 Outbreak ‐ vaccine matching (circulating strains) ‐ community ‐ healthy

2

2047

Risk Ratio (M‐H, Random, 95% CI)

0.57 [0.42, 0.79]

1.2.2 Outbreak ‐ vaccine matching ‐ community ‐ risk groups

1

490

Risk Ratio (M‐H, Random, 95% CI)

0.87 [0.49, 1.53]

1.2.3 Outbreak ‐ vaccine matching ‐ nursing home ‐ healthy

1

4180

Risk Ratio (M‐H, Random, 95% CI)

0.54 [0.37, 0.80]

1.2.4 Outbreak ‐ vaccine matching ‐ psychiatric hospital

1

177

Risk Ratio (M‐H, Random, 95% CI)

0.35 [0.13, 0.92]

1.3 Pneumonia Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

1.3.1 Outbreak ‐ vaccine matching ‐ community ‐ healthy

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

1.4 All deaths Show forest plot

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

1.4.1 Outbreak ‐ vaccine matching ‐ community ‐ healthy

1

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

Figuras y tablas -
Comparison 1. Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine
Comparison 2. Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

2.1 General malaise Show forest plot

4

2560

Risk Ratio (M‐H, Random, 95% CI)

1.18 [0.87, 1.61]

2.2 Nausea Show forest plot

1

672

Risk Ratio (M‐H, Random, 95% CI)

1.75 [0.74, 4.12]

2.3 Upper respiratory tract symptoms Show forest plot

2

713

Risk Ratio (M‐H, Random, 95% CI)

1.35 [0.90, 2.01]

2.4 Headache Show forest plot

3

2519

Risk Ratio (M‐H, Random, 95% CI)

1.10 [0.76, 1.58]

2.5 Fever Show forest plot

3

2519

Risk Ratio (M‐H, Random, 95% CI)

1.57 [0.92, 2.71]

2.6 Local tenderness/sore arm Show forest plot

4

2560

Risk Ratio (M‐H, Random, 95% CI)

3.56 [2.61, 4.87]

2.7 Swelling ‐ erythema ‐ induration Show forest plot

2

1847

Risk Ratio (M‐H, Random, 95% CI)

8.23 [3.98, 17.05]

Figuras y tablas -
Comparison 2. Influenza vaccines versus placebo: randomised controlled trials ‐ parenteral vaccine ‐ adverse events
Comparison 3. Influenza vaccines versus placebo: randomised controlled trials ‐ inactivated aerosol vaccine

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

3.1 Influenza Show forest plot

1

176

Risk Ratio (M‐H, Random, 95% CI)

0.89 [0.40, 1.99]

3.1.1 Outbreak ‐ vaccine matching ‐ psychiatric hospital

1

176

Risk Ratio (M‐H, Random, 95% CI)

0.89 [0.40, 1.99]

3.2 Influenza‐like illness Show forest plot

1

176

Risk Ratio (M‐H, Random, 95% CI)

0.84 [0.41, 1.71]

3.2.1 Outbreak ‐ vaccine matching ‐ psychiatric hospital

1

176

Risk Ratio (M‐H, Random, 95% CI)

0.84 [0.41, 1.71]

Figuras y tablas -
Comparison 3. Influenza vaccines versus placebo: randomised controlled trials ‐ inactivated aerosol vaccine
Comparison 4. Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

4.1 Influenza Show forest plot

1

220

Risk Ratio (M‐H, Random, 95% CI)

0.49 [0.21, 1.17]

4.1.1 No outbreak ‐ vaccine matching ‐ nursing home ‐ healthy and ill

1

220

Risk Ratio (M‐H, Random, 95% CI)

0.49 [0.21, 1.17]

Figuras y tablas -
Comparison 4. Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine
Comparison 5. Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

5.1 General malaise Show forest plot

1

45

Risk Ratio (M‐H, Random, 95% CI)

3.09 [0.18, 53.20]

5.2 Fever Show forest plot

1

45

Risk Ratio (M‐H, Random, 95% CI)

1.71 [0.09, 33.24]

5.3 Upper respiratory tract symptoms Show forest plot

1

45

Risk Ratio (M‐H, Random, 95% CI)

1.62 [0.42, 6.29]

5.4 Lower respiratory tract symptoms Show forest plot

1

45

Risk Ratio (M‐H, Random, 95% CI)

2.91 [0.41, 20.48]

Figuras y tablas -
Comparison 5. Influenza vaccines versus placebo: randomised controlled trials ‐ live aerosol vaccine ‐ adverse events
Comparison 6. Influenza vaccines versus no vaccination: cohort studies in nursing homes

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

6.1 Influenza Show forest plot

8

1941

Risk Ratio (M‐H, Random, 95% CI)

0.65 [0.32, 1.29]

6.1.1 Outbreak ‐ vaccine matching

4

658

Risk Ratio (M‐H, Random, 95% CI)

1.04 [0.43, 2.51]

6.1.2 Outbreak ‐ vaccine matching absent or unknown

2

592

Risk Ratio (M‐H, Random, 95% CI)

0.47 [0.22, 1.04]

6.1.3 No outbreak ‐ vaccine matching

2

691

Risk Ratio (M‐H, Random, 95% CI)

0.23 [0.05, 1.03]

6.1.4 No outbreak ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

6.2 Influenza‐like illness Show forest plot

26

12388

Risk Ratio (M‐H, Random, 95% CI)

0.76 [0.66, 0.88]

6.2.1 Outbreak ‐ vaccine matching (circulating strains)

16

5963

Risk Ratio (M‐H, Random, 95% CI)

0.77 [0.64, 0.94]

6.2.2 Outbreak ‐ vaccine matching absent or unknown

6

4096

Risk Ratio (M‐H, Random, 95% CI)

0.80 [0.60, 1.05]

6.2.3 No outbreak ‐ vaccine matching

4

2329

Risk Ratio (M‐H, Random, 95% CI)

0.67 [0.46, 0.98]

6.2.4 No outbreak ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

6.3 Pneumonia Show forest plot

17

10274

Risk Ratio (M‐H, Random, 95% CI)

0.53 [0.43, 0.66]

6.3.1 Outbreak ‐ vaccine matching

8

4482

Risk Ratio (M‐H, Random, 95% CI)

0.54 [0.42, 0.70]

6.3.2 Outbreak ‐ vaccine matching absent or unknown

5

3991

Risk Ratio (M‐H, Random, 95% CI)

0.68 [0.39, 1.21]

6.3.3 No outbreak ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

6.3.4 No outbreak ‐ matching absent or unknown

4

1801

Risk Ratio (M‐H, Random, 95% CI)

0.35 [0.18, 0.68]

6.4 Hospitalisation for influenza‐like illness or pneumonia Show forest plot

12

28032

Risk Ratio (M‐H, Random, 95% CI)

0.51 [0.32, 0.81]

6.4.1 Outbreak ‐ vaccine matching

8

2027

Risk Ratio (M‐H, Random, 95% CI)

0.55 [0.36, 0.84]

6.4.2 Outbreak ‐ vaccine matching absent or unknown

2

3301

Risk Ratio (M‐H, Random, 95% CI)

0.82 [0.43, 1.58]

6.4.3 No outbreak ‐ vaccine matching

2

22704

Risk Ratio (M‐H, Random, 95% CI)

0.32 [0.14, 0.76]

6.4.4 No outbreak ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

6.5 Deaths from flu or pneumonia Show forest plot

27

32179

Risk Ratio (M‐H, Random, 95% CI)

0.46 [0.33, 0.63]

6.5.1 Outbreak ‐ vaccine matching

16

6127

Risk Ratio (M‐H, Random, 95% CI)

0.58 [0.41, 0.83]

6.5.2 Outbreak ‐ vaccine matching absent or unknown

4

1089

Risk Ratio (M‐H, Random, 95% CI)

0.34 [0.11, 1.02]

6.5.3 No outbreak ‐ vaccine matching

3

23162

Risk Ratio (M‐H, Random, 95% CI)

0.27 [0.09, 0.87]

6.5.4 No outbreak ‐ vaccine matching absent or unknown

4

1801

Risk Ratio (M‐H, Random, 95% CI)

0.30 [0.14, 0.67]

6.6 All deaths Show forest plot

1

305

Risk Ratio (M‐H, Random, 95% CI)

0.40 [0.21, 0.77]

6.6.1 Outbreak ‐ vaccine matching

1

305

Risk Ratio (M‐H, Random, 95% CI)

0.40 [0.21, 0.77]

6.6.2 Outbreak ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

6.6.3 No outbreak ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

6.6.4 No outbreak ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

6.7 Influenza cases (clinically defined without clear definition) Show forest plot

7

24238

Risk Ratio (M‐H, Random, 95% CI)

0.52 [0.27, 1.02]

6.7.1 Outbreak ‐ vaccine matching

2

271

Risk Ratio (M‐H, Random, 95% CI)

0.70 [0.11, 4.56]

6.7.2 Outbreak ‐ vaccine matching absent or unknown

1

155

Risk Ratio (M‐H, Random, 95% CI)

0.23 [0.09, 0.59]

6.7.3 No outbreak ‐ vaccine matching

1

22462

Risk Ratio (M‐H, Random, 95% CI)

0.40 [0.35, 0.46]

6.7.4 No outbreak ‐ vaccine matching absent or unknown

3

1350

Risk Ratio (M‐H, Random, 95% CI)

0.72 [0.41, 1.28]

Figuras y tablas -
Comparison 6. Influenza vaccines versus no vaccination: cohort studies in nursing homes
Comparison 7. Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in nursing homes

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

7.1 Influenza‐like illness Show forest plot

1

1198

Odds Ratio (M‐H, Random, 95% CI)

0.52 [0.40, 0.68]

7.1.1 Outbreak ‐ vaccine matching

1

1198

Odds Ratio (M‐H, Random, 95% CI)

0.52 [0.40, 0.68]

Figuras y tablas -
Comparison 7. Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in nursing homes
Comparison 8. Influenza vaccines versus no vaccination: cohort studies in community‐dwellers

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

8.1 Influenza Show forest plot

2

18249

Risk Ratio (M‐H, Random, 95% CI)

0.19 [0.02, 2.01]

8.1.1 Epidemic year ‐ vaccine matching

1

427

Risk Ratio (M‐H, Random, 95% CI)

0.05 [0.01, 0.37]

8.1.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.1.3 Non‐epidemic year ‐ vaccine matching

1

17822

Risk Ratio (M‐H, Random, 95% CI)

0.50 [0.27, 0.91]

8.1.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.2 Influenza‐like illness Show forest plot

4

9613

Risk Ratio (M‐H, Random, 95% CI)

0.75 [0.42, 1.33]

8.2.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.2.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.2.3 Non‐epidemic year ‐ vaccine matching

2

4636

Risk Ratio (M‐H, Random, 95% CI)

1.08 [0.58, 2.03]

8.2.4 Non‐epidemic year ‐ vaccine matching absent or unknown

1

268

Risk Ratio (M‐H, Random, 95% CI)

0.85 [0.16, 4.55]

8.2.5 Epidemic year ‐ vaccine not matching

1

4709

Risk Ratio (M‐H, Random, 95% CI)

0.44 [0.24, 0.81]

8.3 Pneumonia Show forest plot

2

18090

Risk Ratio (M‐H, Random, 95% CI)

0.88 [0.64, 1.20]

8.3.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.3.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.3.3 Non‐epidemic year ‐ vaccine matching

1

17822

Risk Ratio (M‐H, Random, 95% CI)

0.87 [0.63, 1.19]

8.3.4 Non‐epidemic year ‐ vaccine matching absent or unknown

1

268

Risk Ratio (M‐H, Random, 95% CI)

3.00 [0.16, 57.42]

8.4 Hospitalisation for flu or pneumonia Show forest plot

9

784643

Risk Ratio (M‐H, Random, 95% CI)

0.73 [0.62, 0.85]

8.4.1 Epidemic year ‐ vaccine matching

6

727776

Risk Ratio (M‐H, Random, 95% CI)

0.74 [0.62, 0.88]

8.4.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.4.3 Non‐epidemic year ‐ vaccine matching

1

25532

Risk Ratio (M‐H, Random, 95% CI)

0.55 [0.37, 0.83]

8.4.4 Non‐epidemic year ‐ vaccine matching absent or unknown

1

26626

Risk Ratio (M‐H, Random, 95% CI)

0.73 [0.54, 0.99]

8.4.5 Epidemic year ‐ vaccine not matching

1

4709

Risk Ratio (M‐H, Random, 95% CI)

0.89 [0.33, 2.40]

8.5 Hospitalisation for any respiratory disease Show forest plot

5

567299

Risk Ratio (M‐H, Random, 95% CI)

0.88 [0.54, 1.43]

8.5.1 Epidemic year ‐ vaccine matching

3

515141

Risk Ratio (M‐H, Random, 95% CI)

0.78 [0.37, 1.64]

8.5.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.5.3 Non‐epidemic year ‐ vaccine matching

1

25532

Risk Ratio (M‐H, Random, 95% CI)

0.94 [0.79, 1.12]

8.5.4 Non‐epidemic year ‐ vaccine matching absent or unknown

1

26626

Risk Ratio (M‐H, Random, 95% CI)

1.16 [1.01, 1.34]

8.6 Deaths from flu or pneumonia Show forest plot

1

163391

Risk Ratio (M‐H, Random, 95% CI)

0.87 [0.70, 1.09]

8.6.1 Epidemic year ‐ vaccine matching

1

163391

Risk Ratio (M‐H, Random, 95% CI)

0.87 [0.70, 1.09]

8.6.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.6.3 Non‐epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.6.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.7 Deaths from respiratory disease Show forest plot

1

426668

Risk Ratio (M‐H, Random, 95% CI)

1.32 [1.25, 1.39]

8.7.1 Epidemic year ‐ vaccine matching

1

426668

Risk Ratio (M‐H, Random, 95% CI)

1.32 [1.25, 1.39]

8.8 All deaths Show forest plot

8

409468

Risk Ratio (M‐H, Random, 95% CI)

0.61 [0.47, 0.80]

8.8.1 Epidemic year ‐ vaccine matching

4

300332

Risk Ratio (M‐H, Random, 95% CI)

0.59 [0.50, 0.70]

8.8.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.8.3 Non‐epidemic year ‐ vaccine matching

3

104427

Risk Ratio (M‐H, Random, 95% CI)

0.65 [0.30, 1.39]

8.8.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.8.5 Epidemic year ‐ vaccine not matching

1

4709

Risk Ratio (M‐H, Random, 95% CI)

3.89 [0.90, 16.89]

8.9 Hospitalisation for heart disease Show forest plot

6

433934

Risk Ratio (M‐H, Random, 95% CI)

0.87 [0.67, 1.12]

8.9.1 Epidemic year ‐ vaccine matching

4

381776

Risk Ratio (M‐H, Random, 95% CI)

0.74 [0.56, 0.97]

8.9.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

8.9.3 Non‐epidemic year ‐ vaccine matching

1

25532

Risk Ratio (M‐H, Random, 95% CI)

1.06 [0.81, 1.38]

8.9.4 Non‐epidemic year ‐ vaccine matching absent or unknown

1

26626

Risk Ratio (M‐H, Random, 95% CI)

1.59 [1.07, 2.36]

8.10 Combined outcome: all deaths or severe respiratory illness Show forest plot

3

290819

Risk Ratio (M‐H, Random, 95% CI)

0.71 [0.58, 0.85]

8.10.1 Epidemic year ‐ vaccine matching

2

132365

Risk Ratio (M‐H, Random, 95% CI)

0.80 [0.42, 1.55]

8.10.2 Epidemic year ‐ vaccine matching absent or unknown

1

158454

Risk Ratio (M‐H, Random, 95% CI)

0.74 [0.69, 0.80]

Figuras y tablas -
Comparison 8. Influenza vaccines versus no vaccination: cohort studies in community‐dwellers
Comparison 9. Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

9.1 Hospitalisation for influenza or pneumonia Show forest plot

8

Odds Ratio (IV, Random, 95% CI)

0.73 [0.67, 0.79]

9.1.1 Epidemic ‐ vaccine matching

6

Odds Ratio (IV, Random, 95% CI)

0.71 [0.65, 0.77]

9.1.2 Non‐epidemic ‐ vaccine not matching

1

Odds Ratio (IV, Random, 95% CI)

0.90 [0.58, 1.38]

9.1.3 Epidemic year ‐ vaccine matching absent or unknown

1

Odds Ratio (IV, Random, 95% CI)

0.82 [0.68, 0.98]

9.2 Hospitalisation for any respiratory disease Show forest plot

13

Odds Ratio (IV, Random, 95% CI)

0.78 [0.72, 0.85]

9.2.1 Epidemic ‐ vaccine matching

9

Odds Ratio (IV, Random, 95% CI)

0.71 [0.67, 0.74]

9.2.2 Non‐epidemic ‐ vaccine not matching

2

Odds Ratio (IV, Random, 95% CI)

0.91 [0.76, 1.08]

9.2.3 Non‐epidemic year ‐ vaccine matching

2

Odds Ratio (IV, Random, 95% CI)

0.94 [0.84, 1.06]

9.3 Hospitalisation for heart disease Show forest plot

6

Odds Ratio (IV, Random, 95% CI)

0.76 [0.70, 0.82]

9.3.1 Epidemic year ‐ vaccine matching

5

Odds Ratio (IV, Random, 95% CI)

0.75 [0.70, 0.82]

9.3.2 Non‐epidemic ‐ vaccine not matching

1

Odds Ratio (IV, Random, 95% CI)

0.80 [0.55, 1.16]

9.4 All deaths Show forest plot

7

Odds Ratio (IV, Random, 95% CI)

0.53 [0.46, 0.61]

9.4.1 Epidemic year ‐ vaccine matching

5

Odds Ratio (IV, Random, 95% CI)

0.47 [0.42, 0.53]

9.4.2 Epidemic year ‐ vaccine matching absent or unknown

1

Odds Ratio (IV, Random, 95% CI)

0.65 [0.57, 0.75]

9.4.3 Non‐epidemic year ‐ vaccine matching

1

Odds Ratio (IV, Random, 95% CI)

0.76 [0.60, 0.97]

9.5 Combined outcome: all deaths or severe respiratory illness Show forest plot

1

Odds Ratio (IV, Random, 95% CI)

0.70 [0.37, 1.34]

9.5.1 Epidemic year ‐ vaccine matching

1

Odds Ratio (IV, Random, 95% CI)

0.70 [0.37, 1.34]

Figuras y tablas -
Comparison 9. Influenza vaccines versus no vaccination: cohort studies in community ‐ adjusted rates
Comparison 10. Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

10.1 Influenza Show forest plot

1

6423

Risk Ratio (M‐H, Random, 95% CI)

0.40 [0.14, 1.17]

10.1.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.1.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.1.3 Non‐epidemic year ‐ vaccine matching

1

6423

Risk Ratio (M‐H, Random, 95% CI)

0.40 [0.14, 1.17]

10.1.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.2 Pneumonia Show forest plot

1

6423

Risk Ratio (M‐H, Random, 95% CI)

1.22 [0.76, 1.94]

10.2.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.2.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.2.3 Non‐epidemic year ‐ vaccine matching

1

6423

Risk Ratio (M‐H, Random, 95% CI)

1.22 [0.76, 1.94]

10.2.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.3 Hospitalisation for influenza or pneumonia Show forest plot

1

45932

Risk Ratio (M‐H, Random, 95% CI)

0.74 [0.63, 0.86]

10.3.1 Epidemic year ‐ vaccine matching

1

45932

Risk Ratio (M‐H, Random, 95% CI)

0.74 [0.63, 0.86]

10.3.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.3.3 Non‐epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.3.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.4 Hospitalisation for any respiratory disease Show forest plot

2

189004

Risk Ratio (M‐H, Random, 95% CI)

0.85 [0.80, 0.92]

10.4.1 Epidemic year ‐ vaccine matching

2

189004

Risk Ratio (M‐H, Random, 95% CI)

0.85 [0.80, 0.92]

10.4.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.4.3 Non‐epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.4.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.5 Deaths from respiratory disease Show forest plot

1

142464

Risk Ratio (M‐H, Random, 95% CI)

0.92 [0.86, 0.98]

10.5.1 Epidemic year ‐ vaccine matching

1

142464

Risk Ratio (M‐H, Random, 95% CI)

0.92 [0.86, 0.98]

10.6 All deaths Show forest plot

3

68032

Risk Ratio (M‐H, Random, 95% CI)

0.39 [0.16, 0.97]

10.6.1 Epidemic year ‐ vaccine matching

1

2344

Risk Ratio (M‐H, Random, 95% CI)

0.13 [0.02, 0.92]

10.6.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.6.3 Non‐epidemic year ‐ vaccine matching

2

65688

Risk Ratio (M‐H, Random, 95% CI)

0.47 [0.17, 1.28]

10.6.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.7 Hospitalisation for heart disease Show forest plot

1

45932

Risk Ratio (M‐H, Random, 95% CI)

0.92 [0.83, 1.03]

10.7.1 Epidemic year ‐ vaccine matching

1

45932

Risk Ratio (M‐H, Random, 95% CI)

0.92 [0.83, 1.03]

10.7.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.7.3 Non‐epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.7.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

10.8 Combined outcome: all deaths or severe respiratory illness Show forest plot

2

146248

Risk Ratio (M‐H, Random, 95% CI)

0.60 [0.49, 0.74]

10.8.1 Epidemic year ‐ vaccine matching

1

54438

Risk Ratio (M‐H, Random, 95% CI)

0.54 [0.49, 0.60]

10.8.2 Epidemic year ‐ vaccine matching absent or unknown

1

91810

Risk Ratio (M‐H, Random, 95% CI)

0.67 [0.61, 0.72]

Figuras y tablas -
Comparison 10. Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ risk groups
Comparison 11. Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

11.1 Influenza Show forest plot

1

11399

Risk Ratio (M‐H, Random, 95% CI)

0.57 [0.27, 1.17]

11.1.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.1.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.1.3 Non‐epidemic year ‐ vaccine matching

1

11399

Risk Ratio (M‐H, Random, 95% CI)

0.57 [0.27, 1.17]

11.1.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.2 Pneumonia Show forest plot

1

11399

Risk Ratio (M‐H, Random, 95% CI)

0.59 [0.37, 0.92]

11.2.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.2.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.2.3 Non‐epidemic year ‐ vaccine matching

1

11399

Risk Ratio (M‐H, Random, 95% CI)

0.59 [0.37, 0.92]

11.2.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.3 Hospitalisation for influenza or pneumonia Show forest plot

1

101619

Risk Ratio (M‐H, Random, 95% CI)

0.50 [0.40, 0.63]

11.3.1 Epidemic year ‐ vaccine matching

1

101619

Risk Ratio (M‐H, Random, 95% CI)

0.50 [0.40, 0.63]

11.3.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.3.3 Non‐epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.3.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.4 Hospitalisation for any respiratory disease Show forest plot

2

376324

Risk Ratio (M‐H, Random, 95% CI)

0.84 [0.55, 1.27]

11.4.1 Epidemic year ‐ vaccine matching

2

376324

Risk Ratio (M‐H, Random, 95% CI)

0.84 [0.55, 1.27]

11.4.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.4.3 Non‐epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.4.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.5 Deaths from respiratory disease Show forest plot

1

281424

Risk Ratio (M‐H, Random, 95% CI)

1.41 [1.31, 1.53]

11.5.1 Epidemic year ‐ vaccine matching

1

281424

Risk Ratio (M‐H, Random, 95% CI)

1.41 [1.31, 1.53]

11.6 All deaths Show forest plot

3

43821

Risk Ratio (M‐H, Random, 95% CI)

0.65 [0.33, 1.29]

11.6.1 Epidemic year ‐ vaccine matching

1

7047

Risk Ratio (M‐H, Random, 95% CI)

1.09 [0.26, 4.49]

11.6.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.6.3 Non‐epidemic year ‐ vaccine matching

2

36774

Risk Ratio (M‐H, Random, 95% CI)

0.59 [0.27, 1.30]

11.6.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.7 Hospitalisation for heart disease Show forest plot

1

101619

Risk Ratio (M‐H, Random, 95% CI)

0.79 [0.61, 1.01]

11.7.1 Epidemic year ‐ vaccine matching

1

101619

Risk Ratio (M‐H, Random, 95% CI)

0.79 [0.61, 1.01]

11.7.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.7.3 Non‐epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.7.4 Non‐epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

11.8 Combined outcome: all deaths or severe respiratory illness Show forest plot

2

135180

Risk Ratio (M‐H, Random, 95% CI)

0.62 [0.54, 0.70]

11.8.1 Epidemic year ‐ vaccine matching

1

68536

Risk Ratio (M‐H, Random, 95% CI)

0.65 [0.54, 0.78]

11.8.2 Epidemic year ‐ vaccine matching absent or unknown

1

66644

Risk Ratio (M‐H, Random, 95% CI)

0.58 [0.48, 0.71]

Figuras y tablas -
Comparison 11. Influenza vaccines versus no vaccination: cohort studies in community‐dwellers ‐ no risk groups
Comparison 12. Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

12.1 Influenza‐like illness Show forest plot

1

374

Risk Ratio (M‐H, Random, 95% CI)

0.32 [0.16, 0.64]

12.1.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

12.1.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

12.1.3 Non‐epidemic year ‐ vaccine matching

1

374

Risk Ratio (M‐H, Random, 95% CI)

0.32 [0.16, 0.64]

12.2 Hospitalisation for influenza or pneumonia or respiratory disease Show forest plot

3

518748

Risk Ratio (M‐H, Random, 95% CI)

0.67 [0.64, 0.70]

12.2.1 Epidemic year ‐ vaccine matching

2

518374

Risk Ratio (M‐H, Random, 95% CI)

0.67 [0.63, 0.71]

12.2.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

12.2.3 Non‐epidemic year ‐ vaccine matching

1

374

Risk Ratio (M‐H, Random, 95% CI)

0.90 [0.10, 7.97]

12.3 Deaths from influenza or pneumonia Show forest plot

1

259627

Risk Ratio (M‐H, Random, 95% CI)

0.43 [0.33, 0.57]

12.3.1 Epidemic year ‐ vaccine matching

1

259627

Risk Ratio (M‐H, Random, 95% CI)

0.43 [0.33, 0.57]

12.3.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

12.3.3 Non‐epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

12.4 All deaths Show forest plot

2

260001

Risk Ratio (M‐H, Random, 95% CI)

0.44 [0.41, 0.46]

12.4.1 Epidemic year ‐ vaccine matching

1

259627

Risk Ratio (M‐H, Random, 95% CI)

0.44 [0.41, 0.46]

12.4.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

12.4.3 Non‐epidemic year ‐ vaccine matching

1

374

Risk Ratio (M‐H, Random, 95% CI)

1.60 [0.08, 30.65]

Figuras y tablas -
Comparison 12. Influenza and pneumococcal vaccines versus no vaccination: cohort studies in community‐dwellers
Comparison 13. Influenza vaccines with adjuvant versus no vaccination: cohort studies in community‐dwellers

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

13.1 Influenza‐like illness Show forest plot

2

498

Risk Ratio (M‐H, Random, 95% CI)

0.30 [0.16, 0.56]

13.1.1 Epidemic year ‐ vaccine matching

1

263

Risk Ratio (M‐H, Random, 95% CI)

0.20 [0.07, 0.54]

13.1.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

13.1.3 Non‐epidemic year ‐ vaccine matching

1

235

Risk Ratio (M‐H, Random, 95% CI)

0.38 [0.18, 0.82]

13.2 Hospitalisation for influenza or pneumonia or respiratory disease Show forest plot

2

498

Risk Ratio (M‐H, Random, 95% CI)

0.17 [0.02, 1.28]

13.2.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

13.2.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

13.2.3 Non‐epidemic year ‐ vaccine matching

2

498

Risk Ratio (M‐H, Random, 95% CI)

0.17 [0.02, 1.28]

13.3 All deaths Show forest plot

1

235

Risk Ratio (M‐H, Random, 95% CI)

2.10 [0.10, 43.10]

13.3.1 Epidemic year ‐ vaccine matching

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

13.3.2 Epidemic year ‐ vaccine matching absent or unknown

0

0

Risk Ratio (M‐H, Random, 95% CI)

Not estimable

13.3.3 Non‐epidemic year ‐ vaccine matching

1

235

Risk Ratio (M‐H, Random, 95% CI)

2.10 [0.10, 43.10]

Figuras y tablas -
Comparison 13. Influenza vaccines with adjuvant versus no vaccination: cohort studies in community‐dwellers
Comparison 14. Influenza vaccines versus no vaccination: case‐control studies in community

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

14.1 Hospitalisations for influenza or pneumonia Show forest plot

2

1074

Odds Ratio (M‐H, Random, 95% CI)

0.89 [0.69, 1.15]

14.1.1 Outbreak ‐ vaccine matching (circulating strains)

0

0

Odds Ratio (M‐H, Random, 95% CI)

Not estimable

14.1.2 Outbreak ‐ vaccine matching absent or unknown

1

825

Odds Ratio (M‐H, Random, 95% CI)

0.92 [0.69, 1.22]

14.1.3 No outbreak ‐ vaccine matching

1

249

Odds Ratio (M‐H, Random, 95% CI)

0.82 [0.48, 1.40]

14.2 Hospitalisations for any respiratory disease Show forest plot

4

21378

Odds Ratio (M‐H, Random, 95% CI)

1.08 [0.95, 1.23]

14.2.1 Outbreak ‐ vaccine matching

3

20582

Odds Ratio (M‐H, Random, 95% CI)

1.08 [0.92, 1.26]

14.2.2 No outbreak ‐ not matching

1

796

Odds Ratio (M‐H, Random, 95% CI)

1.02 [0.68, 1.52]

14.3 Deaths from influenza or pneumonia Show forest plot

1

1092

Odds Ratio (M‐H, Random, 95% CI)

0.74 [0.53, 1.04]

14.3.1 Outbreak ‐ vaccine matching

1

1092

Odds Ratio (M‐H, Random, 95% CI)

0.74 [0.53, 1.04]

14.4 Pneumonia (no better defined) Show forest plot

1

519

Odds Ratio (M‐H, Fixed, 95% CI)

0.87 [0.57, 1.33]

14.4.1 Outbreak ‐ partially matching

1

519

Odds Ratio (M‐H, Fixed, 95% CI)

0.87 [0.57, 1.33]

Figuras y tablas -
Comparison 14. Influenza vaccines versus no vaccination: case‐control studies in community
Comparison 15. Influenza vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

15.1 Hospitalisations for influenza or pneumonia Show forest plot

5

Odds Ratio (IV, Random, 95% CI)

0.59 [0.47, 0.74]

15.1.1 Epidemic ‐ vaccine matching

1

Odds Ratio (IV, Random, 95% CI)

0.55 [0.36, 0.85]

15.1.2 Non‐epidemic ‐ vaccine not matching

0

Odds Ratio (IV, Random, 95% CI)

Not estimable

15.1.3 Epidemic year ‐ vaccine matching absent or unknown

2

Odds Ratio (IV, Random, 95% CI)

0.68 [0.58, 0.79]

15.1.4 Non‐epidemic ‐ vaccine matching

2

Odds Ratio (IV, Random, 95% CI)

0.37 [0.16, 0.87]

15.2 Hospitalisations for any respiratory disease Show forest plot

3

Odds Ratio (IV, Random, 95% CI)

0.71 [0.56, 0.90]

15.2.1 Epidemic ‐ vaccine matching

3

Odds Ratio (IV, Random, 95% CI)

0.71 [0.56, 0.90]

15.2.2 Non‐epidemic ‐ vaccine matching

0

Odds Ratio (IV, Random, 95% CI)

Not estimable

15.2.3 Non‐epidemic year ‐ vaccine matching

0

Odds Ratio (IV, Random, 95% CI)

Not estimable

15.3 Deaths from pneumonia or influenza Show forest plot

2

Odds Ratio (IV, Random, 95% CI)

0.74 [0.60, 0.92]

15.3.1 Epidemic year ‐ vaccine matching

1

Odds Ratio (IV, Random, 95% CI)

0.76 [0.60, 0.97]

15.3.2 Epidemic year ‐ vaccine matching absent or unknown

1

Odds Ratio (IV, Random, 95% CI)

0.67 [0.42, 1.07]

Figuras y tablas -
Comparison 15. Influenza vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates
Comparison 16. Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in community

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

16.1 Hospitalisations for influenza or pneumonia Show forest plot

4

6629

Odds Ratio (M‐H, Random, 95% CI)

0.97 [0.85, 1.09]

16.1.1 Outbreak ‐ vaccine matching

2

3617

Odds Ratio (M‐H, Random, 95% CI)

0.95 [0.69, 1.31]

16.1.2 No outbreak ‐ vaccine matching

2

3012

Odds Ratio (M‐H, Random, 95% CI)

0.93 [0.80, 1.08]

Figuras y tablas -
Comparison 16. Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in community
Comparison 17. Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

17.1 Hospitalisations for influenza or pneumonia Show forest plot

2

Odds Ratio (IV, Random, 95% CI)

0.68 [0.54, 0.86]

17.1.1 Epidemic ‐ vaccine matching

1

Odds Ratio (IV, Random, 95% CI)

0.68 [0.50, 0.93]

17.1.2 Non‐epidemic ‐ vaccine not matching

0

Odds Ratio (IV, Random, 95% CI)

Not estimable

17.1.3 Epidemic year ‐ vaccine matching absent or unknown

0

Odds Ratio (IV, Random, 95% CI)

Not estimable

17.1.4 Non‐epidemic ‐ vaccine matching

1

Odds Ratio (IV, Random, 95% CI)

0.69 [0.49, 0.97]

Figuras y tablas -
Comparison 17. Influenza and pneumococcal vaccines versus no vaccination: case‐control studies in community ‐ adjusted rates
Comparison 18. Sensitivity analysis: comparison 01: subgroup analysis by study quality

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

18.1 Influenza‐like illness Show forest plot

25

9211

Risk Ratio (M‐H, Random, 95% CI)

0.75 [0.65, 0.87]

18.1.1 Quality A

8

4502

Risk Ratio (M‐H, Random, 95% CI)

0.78 [0.65, 0.94]

18.1.2 Quality B

13

3854

Risk Ratio (M‐H, Random, 95% CI)

0.82 [0.65, 1.03]

18.1.3 Quality C

3

389

Risk Ratio (M‐H, Random, 95% CI)

0.66 [0.43, 1.00]

18.1.4 Quality D

1

466

Risk Ratio (M‐H, Random, 95% CI)

0.44 [0.35, 0.57]

Figuras y tablas -
Comparison 18. Sensitivity analysis: comparison 01: subgroup analysis by study quality