Influenza vaccination in patients with asthma: effect on peak expiratory flow, asthma symptoms and use of medication.

This pilot study was undertaken to examine whether killed influenza vaccine causes exacerbations in asthmatic adults. Thirty-three stable asthmatics recorded peak expiratory flow (PEF), asthma symptoms, and use of asthma medication for 2 weeks, and then received killed influenza vaccine. Thereafter they recorded PEF, asthma symptoms and use of medication for a further 2 weeks. Comparison of recordings during the 2 weeks before and after vaccination revealed that influenza vaccine was not associated with reduction in PEF (P = 0.76), increase in asthma symptoms (P = 0.17) or use of asthma medication (P = 0.58). Similar results for PEF (P = 0.49), asthma symptoms (P = 0.17), and asthma medication (P = 0.16) were obtained when the analysis was restricted to the 2 days before and after vaccination.