BACKGROUND: The risks of influenza vaccination in asthmatic children are still being discussed. Especially, the risk that influenza vaccination may exacerbate asthma is an issue in this debate.
METHODS: We conducted a randomised double-blind placebo-controlled trial in 696 children 6-18 years of age with asthma recruited in general practice during two influenza seasons, 1999-2000 and 2000-2001. Children participated for only one season. During the first week after vaccination, participants recorded local, influenza like and asthma symptoms as well as use of medication, health care use and absenteeism.
RESULTS: Except for cough during the day in the first season, favouring placebo, there were no differences indicating that vaccination exacerbates asthma.
CONCLUSIONS: Influenza vaccination does not seem to exacerbate asthma.