Clinical features, oseltamivir treatment and outcome in infants aged <12 months with laboratory-confirmed influenza A in 2009

Antivir Ther. 2011;16(7):1005-10. doi: 10.3851/IMP1848.


Background: Data on the use of oseltamivir in infants is limited. We documented the clinical presentations of infants aged <12 months hospitalized with laboratory-confirmed influenza A in the southern hemisphere winter of 2009 and compared outcomes in relation to oseltamivir therapy.

Methods: Data were extracted from prospectively collected and collated influenza case reports (June-September 2009) ascertained through Paediatric Active Enhanced Disease Surveillance, an in-patient surveillance system operating at the Children's Hospital at Westmead (CHW), Sydney, NSW, Australia. Nosocomial cases were excluded.

Results: Of 56 infants with definite influenza (35 pandemic H1N1 2009) admitted to the CHW, 20 were treated with oseltamivir. Overall, 12 (60%) of those treated with oseltamivir were aged <6 months. Cough, fever and coryza were the most common clinical features (≥70%). Vomiting was present on admission in 31.4%. All 7 cases presenting with vomiting then given antiviral treatment had reduction of vomiting and the other 13 did not develop vomiting on treatment. There were three infants with hypoxaemia (oxygen saturation ≤93%) on presentation in the treatment group compared with none in the control group (P=0.04). The median duration of hospital stay was the same in both groups (2.5 days).

Conclusions: The use of oseltamivir was well tolerated in hospitalized infants. Vomiting, one of the widely reported side effects of oseltamivir, was found to be more a presenting symptom of influenza than a side effect of oseltamivir. Based on pulse oximetry, oseltamivir-treated cases may have been more severe on presentation, but there was no significant difference in length of hospital stay.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antiviral Agents / adverse effects
  • Antiviral Agents / therapeutic use*
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Influenza A virus / drug effects*
  • Influenza A virus / immunology
  • Influenza A virus / pathogenicity
  • Influenza, Human / drug therapy*
  • Male
  • Oseltamivir / administration & dosage
  • Oseltamivir / adverse effects
  • Oseltamivir / therapeutic use*
  • Treatment Outcome


  • Antiviral Agents
  • Oseltamivir