Influenza vaccination in asthma: efficacy and side‐effects
Abstract
Objectives
To assess the efficacy and side‐effects of influenza vaccination in preventing morbidity and mortality in asthmatic patients.
Search methods
Randomised controlled trials were identified from the Cochrane Airways Group Asthma Register which is a compilation of systematic searches of CINAHL, EMBASE and MEDLINE and hand searching of 20 respiratory journals.
Selection criteria
All randomised controlled trials involving asthmatic children (over 2 years of age) or adults given any type of influenza vaccination were included. Outcome measures included exacerbation rate, admission to hospital, pneumonia, asthma symptom scores, lung function measurements and mortality. These were separately analysed for the week following immunisation (adverse effects) and the following six months (protective effects). Two reviewers independently selected potentially relevant abstracts identified from the register and assessed the full papers for inclusion and methodological quality. Tests for agreement between reviewers were performed.
Data collection and analysis
Data extraction was performed by two reviewers and checked with the authors where possible. Missing data was obtained from the authors where possible. Data were analysed using Review Manager version 3.1. Sensitivity analyses and sub‐group analyses were not possible due to the lack of suitable data.
Main results
Nine studies were included in this review, of which four were of high methodological quality. There are currently no data from randomised controlled trials to confirm the protective effect of influenza vaccination against asthma exacerbation due to influenza infection. Furthermore, one well designed study [Nicholson, 1998] has shown a small additional risk of asthma exacerbation following administration of inactivated influenza vaccine in adults (Risk Difference 3.1%, 95% Confidence Interval 0.3% to 5.8%).
Authors' conclusions
Large randomised placebo‐controlled trials are required to further assess the benefits and risks of different influenza vaccinations for asthmatic patients in the community.
