Background: A systematic review examining the efficacy of antibiotics in acute respiratory illness concluded that antibiotics are of little benefit. However, that review was based on analysis of only six randomized controlled trials, one of which was excluded because its analysis included patients with multiple episodes of illness; treatment group, either antibiotic or placebo, might have confounded the likelihood of suffering a subsequent episode of illness.
Methods: This previously excluded randomized controlled trial of 301 patients with symptoms of minor respiratory illness was re-analysed to examine the efficacy of antibiotic versus placebo in terms of resolution of symptoms, most particularly cough.
Results: Antibiotic had no impact on the resolution of symptoms of cough at 1 and 2 weeks, respectively; adjusted odds ratio 1.2 [95% confidence interval (CI) 0.7--2.1] and 0.8 (95% CI 0.4--1.6). In those 220 (73%) individuals who suffered a cough, 48 (44%) and 19 (17%) of patients taking placebo were still coughing after 1 and 2 weeks, respectively.
Conclusion: It appears that an antibiotic is likely to have, at best, a marginal impact on resolution of symptoms for most patients with minor respiratory illness in the community.