Oseltamivir and zanamivir appear to have modest benefit in reducing duration of illness in children with influenza. However, our analysis was limited by small sample sizes and an inability to pool data from different studies. In addition, the inclusion of data from published trials only may have resulted in significant publication bias. Based on published trial data, oseltamivir reduces the incidence of acute otitis media in children aged one to five years but is associated with a significantly increased risk of vomiting. One study demonstrated that laninamivir octanoate was more effective than oseltamivir in shortening duration of illness in children with oseltamivir-resistant influenza A/H1N1. The benefit of oseltamivir and zanamivir in preventing the transmission of influenza in households is modest and based on weak evidence. However, the clinical efficacy of neuraminidase inhibitors in 'at risk' children is still uncertain. Larger high-quality trials are needed with sufficient power to determine the efficacy of neuraminidase inhibitors in preventing serious complications of influenza (such as pneumonia or hospital admission), particularly in 'at risk' groups.
Zanamivir prophylaxis: an effective strategy for the prevention of influenza types A and B within households.
A double-blind, randomized study of inhaled zanamivir for the prevention of influenza in families was conducted. Once a person with a suspected case of influenza was identified (index patient), treatment of all other household members (contacts) > or =5 years old was initiated. Contacts received either 10 mg zanamivir or placebo inhaled once daily for 10 days. Index patients received relief medication only. In total, 487 households (242 placebo and 245 zanamivir) were enrolled, with 1291 contacts randomly assigned to receive prophylaxis. Four percent of zanamivir versus 19% of placebo households (P<.001) had at least 1 contact who developed symptomatic, laboratory-confirmed influenza, representing 81% protective efficacy (95% confidence interval, 64%-90%). Protective efficacy was similarly high for individuals (82%) and against both influenza types A and B (78% and 85%, respectively, for households). Zanamivir was well tolerated and was effective in preventing influenza types A and B within households where the index patient was not treated.