Meta-Analysis: Oseltamivir Linked to Modest Improvements in Adults' Flu Symptoms

By Kelly Young

Edited by André Sofair, MD, MPH

Oseltamivir (Tamiflu) is associated with faster resolution of flu symptoms in adults, in addition to lower odds of hospitalization, according to a Lancet meta-analysis. The study was conducted by an independent group that received an unrestricted grant from Tamiflu's manufacturer.

The researchers examined nine trials in which 4300 adults and adolescents with influenza-like illness were randomized to oseltamivir or placebo. Unlike the highly cited 2014 Cochrane analysis, this meta-analysis used patient-level data.

In patients with lab-confirmed influenza, oseltamivir was associated with shorter time to symptom resolution than placebo (4 vs. 5.1 days), fewer hospital admissions (0.6% vs. 1.7% of patients), and fewer lower respiratory tract complications requiring antibiotics (4% vs. 9%). On the other hand, oseltamivir recipients were more likely to have nausea (10% vs. 6%) and vomiting (8% vs. 3%).

Commentators write that in light of the nausea and vomiting risks, "confirmation of the diagnosis of influenza before treatment is advisable. In a pandemic or severe epidemic, oseltamivir can be used presumptively when there is a high probability that influenza-like illness is caused by influenza virus infection and when the outcome of infection is likely to be severe."