BACKGROUND: Despite current recommendations, many @entity1 with @entity565 do not receive annual vaccination against @entity683 , partly because of concern that vaccine may trigger exacerbations. Colds can trigger exacerbations, which may be mistaken for vaccine-related adverse events. We undertook a double-blind placebo-controlled multicentre crossover study to assess the safety of @entity683 vaccine in @entity1 with @entity565 , with allowance for the occurrence of colds. METHODS: We studied 262 @entity1 , aged 18-75 years, who recorded daily peak expiratory flow (PEF), respiratory symptoms, medication, medical consultations, and hospital admissions for 2 weeks before the first injection and until 2 weeks after the second injection. Order of injection (vaccine and placebo) was assigned randomly. There was an interval of 2 weeks between injections. The main outcome measure was an exacerbation of @entity565 within 72 h of injection (defined as a fall in PEF of >20%). FINDINGS: Among 255 @entity1 with paired data, 11 recorded a fall in PEF of more than 20% after vaccine compared with three after placebo (McNemar's test p=0.06); a fall of more than 30% was recorded by eight after vaccine compared with none after placebo (binomial test p=0.008). However, when @entity1 with colds were excluded, there was no significant difference in the numbers with falls of more than 20% between vaccine and placebo (six vs three; binomial test p=0.51), although the difference for PEF decreases of more than 30% approached significance (five vs none; binomial test, p=0.06). This association was confined to first-time vaccinees. INTERPRETATION: Our findings indicate that @entity358 may occur as a complication of @entity683 vaccination. However, the risk of @entity358 is very small and outweighed by the benefits of vaccination.

Randomised placebo-controlled crossover trial on effect of inactivated @entity683 vaccine on pulmonary function in XXXX .

@entity1 :: ('9606', 'Species') :: ['participants', 'patients', 'people'] @entity565 :: ('MESH:D001249', 'Disease') :: ['asthma'] @entity358 :: ('MESH:D008171', 'Disease') :: ['pulmonary-function abnormalities', 'pulmonary complications'] @entity683 :: ('MESH:D007251', 'Disease') :: ['influenza']
@entity565 :: (MESH:D001249,Disease) :: ['asthma']
