J Pediatr Infect Dis 2013; 08(02): 071-081
DOI: 10.3233/JPI-130381
Georg Thieme Verlag KG Stuttgart – New York

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

Takahiro Tahara
a  Tahara Clinic, Yamaguchi, Japan
Yoshizo Asano
b  Fujita Health University School of Medicine, Aichi, Japan
c  Research Center for Zoonosis Control, Hokkaido University, Hokkaido, Japan
Keiko Mitamura
d  Department of Pediatrics, Eiju General Hospital, Tokyo, Japan
Hidefumi Nakamura
e  Division for Clinical Trials, National Center for Child Health and Development, Tokyo, Japan
Susumu Itoh
f  Department of Pediatrics, Kagawa University, Kagawa, Japan
› Author Affiliations

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Further Information

Publication History

28 March 2012

06 March 2013

Publication Date:
28 July 2015 (online)


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.