Respiratory infections for which general practitioners consider prescribing an antibiotic: a prospective study

Objective: To determine the viral aetiology of respiratory infections in children presenting to primary care with "more than a simple cold''. Design: Observational study in 18 Oxfordshire general practices over four winters (2000-01 to 2003-04). Patients: 425 children aged 6 months to 12 years with cough and fever for whom general practitioners considered prescribing an antibiotic. Methods: Nasopharyngeal aspirate obtained from 408 (96%) children was subjected to PCR for respiratory viruses. Parents completed an illness diary for the duration of illness. Results: A viral cause of infection was detected in most (77%) children. Clinical symptoms correctly identified the infecting virus in 45% of cases. The duration of illness was short and the time course was very similar for all infecting viruses. One third of children were prescribed an antibiotic (34%), but this made no difference to the rate of parent-assessed recovery (Kruskal-Wallis, p = 0.67). About one in five children with influenza who did not receive an antibiotic had persistent fever on day 7 compared to no children receiving antibiotics (p = 0.02); this difference remained after adjustment for severity and other factors and was not seen with other viruses. Conclusions: Most children receiving antibiotics for respiratory symptoms in general practice have an identifiable viral illness. In routine clinical practice, neither the specific infecting virus nor the use of antibiotics has a significant effect on the time course of illness. Antibiotics may reduce the duration of fever in children with influenza which could reflect an increased risk of secondary bacterial infection for such children.