Prescribing antibiotics for community acquired respiratory tract infections in primary care involves balancing the risk of missing pneumonia or serious complications on the one hand and treating infections unnecessarily on the other. Recent studies have shown that using antibiotics causes resistance among respiratory pathogens in individuals.1 2 These studies were needed to confirm earlier studies showing an association between antibiotics and resistance at population level and to support prescribing campaigns to combat resistance by optimising antibiotic use.3 But, although optimising the use of antibiotics seems to reduce resistance, it might increase the risk of complications.

In this week's BMJ, Petersen and colleagues assess whether antibiotics protect against serious complications of common respiratory infections.4 They identified 3.36 million episodes of respiratory tract infection recorded between 1991 and 2001 in the UK General Practice Research Database and determined whether complications were less common in people who were prescribed antibiotics than in those who were not.4 They found that in the month after the original diagnosis, pneumonia after upper respiratory …