A Study on Emergence of Resistance With Oseltamivir (Tamiflu) in Participants With Seasonal Influenza

A Phase IIIb, Open-label, Comparative, Randomized Study on Resistance of Influenza A/H1N1 2009 Virus to Treatment With Oseltamivir at Standard Dose Versus Double Dose

This open-label randomized 2 arm study will determine the emergence of viral resistance in participants with seasonal influenza A infection treated with oseltamivir. Eligible participants less than or equal to (</=) 5 years of age will be randomized to receive oseltamivir at either standard dose (30-75 milligrams [mg] orally twice daily [bid]) or double dose (60-150 mg orally bid) for 5 days. Target sample size is greater than (>) 100.

Inclusion Criteria:

• positive rapid antigen test for influenza A
• onset of symptoms of influenza (fever, at least one respiratory symptom) </=48 hours

Exclusion Criteria:

• clinical suspicion of infection with a respiratory virus other than influenza
• suspicion of invasive bacterial infection
• evidence of poorly controlled underlying disease
• known immunosuppression
• known allergy to Oseltamivir
• women who are pregnant or planning to get pregnant during the study