A prospective observational study of oseltamivir safety and tolerability in infants and young children ≤24 months

PurposeInfants and young children are at elevated risk of influenza-associated complications, but information on the safety of antiviral therapies is limited in this age group. MethodsIn this prospective open-label observational safety study, children aged 24months with a clinical diagnosis of influenza in routine practice received either no antiviral treatment (unexposed' group) or oseltamivir treatment or prophylaxis (exposed' group), according to the physician's judgment. Patients were followed up for 30days after the baseline visit. ResultsAdverse events (AEs) were analysed in 1065 patients; they were reported in 390/711 (54.9%) in the unexposed group, 167/340 (49.1%) patients in the exposed group, and 6/14 prophylaxis patients. Cough and rhinitis were the most common events, reported more often in unexposed children (22.9 and 20.3% respectively) than in exposed children (13.2 and 10.0%; p<0.001); pyrexia, diarrhoea and vomiting were less common, occurring at similar rates in exposed and unexposed patients. Nasal congestion (3.5%), bronchitis (5.6%) and upper respiratory tract infection (1.5%) were reported more frequently in exposed patients than in unexposed patients (0.7, 2.7 and 0.1% respectively; p<0.05). In the exposed group, 11.2% of patients (n=38) experienced 41 AEs considered at least possibly related to oseltamivir, none being assessed as serious. Overall, there were 79 serious AEs in 59 patients. Eleven discontinued treatment because of an AE. ConclusionsOseltamivir has a good tolerability profile in infants and children aged 24months. These findings contributed to the recent FDA approval of oseltamivir for treating infants aged 2-51weeks. Copyright (c) 2014 John Wiley & Sons, Ltd.