Vaccines for the common cold
Abstract
Background
The common cold is a spontaneously remitting infection of the upper respiratory tract, characterised by a runny nose, nasal congestion, sneezing, cough, malaise, sore throat, and fever (usually < 37.8º C). The widespread morbidity caused by the common cold worldwide is related to its ubiquitousness rather than its severity. The development of vaccines for the common cold has been difficult because of antigenic variability of the common cold virus and the indistinguishable multiple other viruses and even bacteria acting as infective agents. There is uncertainty regarding the efficacy and safety of interventions for preventing the common cold in healthy people. This is an update of a Cochrane review first published in 2011 and previously updated in 2013.
Objectives
To assess the clinical effectiveness and safety of vaccines for preventing the common cold in healthy people.
Search methods
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (September 2016), MEDLINE (1948 to September 2016), Embase (1974 to September 2016), CINAHL (1981 to September 2016), and LILACS (1982 to September 2016). We also searched three trials registers for ongoing studies and four websites for additional trials (February 2017). We included no language or date restrictions.
Selection criteria
Randomised controlled trials (RCTs) of any virus vaccines compared with placebo to prevent the common cold in healthy people.
Data collection and analysis
Two review authors independently evaluated methodological quality and extracted trial data. We resolved disagreements by discussion or by consulting a third review author.
Main results
We found no additional RCTs for inclusion in this update. This review includes one RCT dating from the 1960s with an overall high risk of bias. The RCT included 2307 healthy participants, all of whom were included in analyses. This trial compared the effect of an adenovirus vaccine against placebo. No statistically significant difference in common cold incidence was found: there were 13 (1.14%) events in 1139 participants in the vaccines group and 14 (1.19%) events in 1168 participants in the placebo group (risk ratio 0.95, 95% confidence interval 0.45 to 2.02; P = 0.90). No adverse events related to the live vaccine were reported. The quality of the evidence was low due to limitations in methodological quality and a wide 95% confidence interval.
Authors' conclusions
This Cochrane Review was based on one study with low‐quality evidence. We found no conclusive results to support the use of vaccines for preventing the common cold in healthy people compared with placebo. We identified a need for well‐designed, adequately powered RCTs to investigate vaccines for the common cold in healthy people. Any future trials on medical treatments for preventing the common cold should assess a variety of virus vaccines for this condition. Outcome measures should include common cold incidence, vaccine safety, and mortality related to the vaccine.
PICOs
Plain language summary
Vaccines for preventing the common cold
Review question
We looked at whether vaccines can help to prevent the common cold.
Background
The common cold is caused by viral infection of the upper respiratory tract, and people usually get better when the virus dies. People with common cold feel unwell, have runny noses, nasal congestion, sneezing, and cough with or without sore throat, and slightly elevated temperatures. Treatments are aimed at relieving symptoms.
Globally, the common cold causes widespread illness. It has been difficult to produce vaccines to prevent the common cold due to the many viruses involved. The effect of vaccines on preventing the common cold in healthy people is still unknown.
Search date
For this update we searched the literature up to 2 September 2016.
Study characteristics
We found no new studies in this update. This review includes one previously identified randomised controlled trial performed in 1965. This study involved 2307 healthy people at a training facility for the United States Navy and evaluated the effect of a live weakened (attenuated) adenovirus vaccine compared to a fake vaccine (placebo).
Study funding sources
This study was funded by a government institution.
Key results
There were no differences in the frequency of occurrence of the common cold between those who received the vaccine compared to those who received a fake vaccine. There were no adverse events related to the vaccine. However, due to the low numbers of people included in the study and numbers of colds, as well as flaws in the study design, our confidence in the results is low. Further research may be able to clarify if vaccines can prevent common cold, since the current evidence does not support the use of adenovirus vaccine to prevent common cold in healthy people.
Quality of the evidence
We assessed the quality of the evidence as low due to high risk of bias and low numbers of people included in the study and numbers of colds, which resulted in imprecision.
