RESUMEN
BACKGROUND: Influenza infection causes significant morbidity and mortality in asthma patients. Accordingly, annual vaccination against influenza is recommended. However, there is concern that vaccination may trigger exacerbations. Colds and insufficient asthma control cause exacerbations, which may be mistaken for vaccine related events. METHODS: We undertook a placebo-controlled crossover study to assess the effect of influenza vaccine on pulmonary function in stable asthma, we enrolled 20 patients, aged 18-65 years, who recorded daily peak flow (PEF), respiratory symptoms, medication, and additional medical consultation for each 2 weeks after placebo and vaccine injection. The primary outcome measure was an exacerbation of lung function within 72h of injection. RESULTS: There was no significant difference in the numbers with falls of more than 20% between vaccine and placebo injection (two vs none, p>0.05). Symptom score, medication doses and additional medical consultation were also indifferent after vaccine and placebo injection. CONCLUSION: The influenza vaccine is safe to administer to adult stable asthmatics.