Slower than anticipated participant accrual

This is a prospective, randomized, double-blind, placebo-controlled trial that will be conducted in tertiary care pediatric hospitals in El Salvador and Panama. The primary purpose of this study is to determine whether empiric oseltamivir phosphate treatment given at the time of hospital admission to children less than 10 years of age hospitalized with influenza can effectively reduce their illness severity. Additional objectives are to: 1) evaluate the tolerability of oseltamivir phosphate treatment, 2) evaluate the effect of oseltamivir treatment on viral clearance and development of oseltamivir-resistant influenza virus during and after treatment in children hospitalized with influenza, 3) estimate the direct and indirect costs of all-cause respiratory illness and influenza-associated respiratory illness requiring hospitalization, and 4) evaluate the effect of empiric oseltamivir treatment during the influenza season on these costs.

The primary study hypothesis is that children with laboratory-confirmed influenza receiving empiric oseltamivir phosphate treatment initiated at the time of hospital admission will have a shorter duration of hospitalization and a shorter time to resolution of signs of severe respiratory illness compared to children receiving placebo. The secondary study hypotheses are that children with laboratory-confirmed influenza receiving oseltamivir phosphate treatment will have a reduction in the time to non-detectable influenza virus and influenza viral RNA and children with all-cause respiratory illness receiving oseltamivir phosphate will not be more likely to experience severe adverse events than children receiving placebo.

Inclusion Criteria:

• Age <10 years
• Accompanied by a parent or guardian who has the capacity to grant and sign the written informed consent and who has consented to enrollment
• Has respiratory illness as defined by modified IMCI criteria for pneumonia:
• Cough or sore throat AND Fast breathing, defined as respiratory rate 60 breaths per minutes or greater for children 0 to <2 months, OR respiratory rate 50 breaths per minute or greater for children 2 to <12 months, OR respiratory rate 40 breaths per minute or greater for children 12 to <60 months, OR respiratory rate 30 breaths per minute or greater for children 5-9 years
• Planned for hospital admission

Exclusion Criteria:

• Symptom onset 7 days or more at the time of study screening where day 1 is the day of symptom onset
• Concomitant severe vomiting illness prior to enrollment that would preclude ability to take medication orally defined as more than 3 vomiting episodes in the preceding 24 hours
• Prematurity (birth at less than 37 weeks gestation) for children aged less than 3 months
• Birth weight less than 2500 grams for children aged less than 3 months
• Chronic supplemental oxygen requirement at home
• Known history of renal dysfunction
• History of gastrointestinal resection resulting in gastrointestinal abnormality that might hinder absorption of oral medication (such as short-gut syndrome)
• History of previous serious adverse reaction to oseltamivir phosphate
• Receipt of oseltamivir phosphate during the 5 days prior to presentation at the admitting hospital
• Previous enrollment in this study during a hospitalization that ended less than 14 days prior to the current admission