Researchers at the University of Nottingham revealed on Monday that people infected with H1N1 influenza during the 2009-2010 pandemic were less likely to die if they were given antiviral drugs such as Tamiflu.
The research, published in The Lancet Respiratory Medicine journal, showed that treatment administered to a patient within two days of showing symptoms cut the risk of death in half, compared with treatment administered later or not at all.
"Many governments have stockpiles of Tamiflu that are close to expiry," Jonathan Nguyen-Van-Tam, a University of Nottingham professor, said. "But until now, they had no adequate data to assist them in deciding if lives were saved in 2009-2010 or not, and whether they should replenish or not."
He said the situation is made more complex because when an influenza pandemic occurs, vaccines arrive six months too late and the benefit to public health is, at best, moderate.
"Thus we are left with antivirals like Tamiflu and public health measures like hand washing and social distancing as the only defenses we have for the first 6 months of a pandemic," Nguyen-Van-Tam said.
Nguyen-Van-Tam and researchers from the Post-pandemic Review of anti-Influenza Drug Effectiveness research consortium completed meta-analysis of patient data to determine the effects of NAI treatment on death in hospitalized patients with confirmed or suspected H1N1 infection.
Analysis of data from 78 studies that involved 29,234 patients revealed that treatment at any time during illness reduced the risk of death by 19 percent, compared to no treatment.
Researchers noted the same survival benefit for pregnant women and adult patients in intensive care. The study, however, did not show significant mortality reduction in children up to 15 years of age.
"Our data suggest that in line with U.S. Centers for Disease Control and Prevention recommendations, treatment guidance policies should emphasize that NAI treatment should be started as soon as possible for any hospitalized adult who presents with influenza that is suspected or confirmed," Nguyen-Van-Tam said. "Since so many patients with severe influenza are not admitted to hospital within 48 hours of symptom onset, the same applies to adults in the community who are appreciably unwell with influenza like illness or who have underlying risk conditions. If clinical suspicion is high, one should not wait for laboratory confirmation before starting treatment."