Bronchiolitis is a serious respiratory illness that often affects young babies. It is most commonly caused by respiratory syncytial virus (RSV) and is the most common reason for hospitalisation in babies under the age of six months. Babies usually present with runny nose, cough, shortness of breath and signs of respiratory distress which can become life-threatening. Despite its viral cause, antibiotics are prescribed in 34% to 99% of cases. Prescribers may be expecting benefits from anti-inflammatory effects attributed to some antibiotics or be concerned about secondary bacterial infection, particularly in children who are very unwell and require intensive care admission.
This systematic review found five trials (543 participants) comparing antibiotics with placebo or no antibiotics. Two of these also compared intravenous and oral antibiotics. Two trials showed that antibiotics are no better than placebo at reducing the length of illness of bronchiolitis and hospitalisation. Two more recent studies comparing antibiotics with no antibiotics found no improvement in the length of illness or hospitalisation. One smaller, poorer quality trial found benefit for antibiotics over placebo for some outcomes. Only one of the five included trials had a low risk of bias. Antibiotics may be justified in children who are very unwell and requiring intensive care admission. Antibiotics need to be used cautiously owing to the potential for side effects, cost to the patient and the community and increasing bacterial resistance to antibiotics.