Safety of oseltamivir in infants less than one year old: Prospective surveillance during the 2004–2005 influenza season in Japan

Abstract

The aim of this study was to investigate the treatment of influenza and safety of oseltamivir in infants less than 1 year of age. All-patient surveillance was conducted using centralized enrolment at 219 medical institutions. Safety data were collected for 1,663 patients less than 1 year of age who developed influenza during the 2004–2005 influenza season. Patients were stratified into three groups: patients not treated with a drug (Group A), patients treated with oseltamivir (Group B), and patients treated with a drug other than an antiviral agent (Group C). Significant differences (P = 0.0074, P < 0.0001) were observed among incidences of adverse events in the three groups (Group A: 26.7%, Group B: 30.0%, Group C: 21.5%) and between the incidences of adverse drug reactions (ADRs) in the two drug-treated groups (Group B: 6.7%, Group C: 0.9%). The most commonly reported ADRs in patients treated with oseltamivir were diarrhoea, hypothermia, vomiting, and rash. We found that 77.2% of patients received oseltamivir and 20.0% received symptomatic treatments such as antipyretic agents. In infants less than 1 year of age, incidence of ADRs with oseltamivir treatment was higher than with symptomatic treatments, however these ADRs were treatable symptoms and consistent with the ADRs reported in young children treated with oseltamivir.

Our analysis of the safety of oseltamivir in infants less than 1 year of age revealed clinical acceptance of safety issues.

Keywords

Infant - under one year old - oseltamivir - influenza virus - drug safety