Report shows effect of antivirals during Mexican H1N1 epidemic

A new study has demonstrated the effectiveness of antiviral medication during Mexico's 2009 H1N1 epidemic but also reports that antiviral use dropped as the epidemic waned.

H1N1 influenza cases tracked through Mexico's social security system showed that antiviral use cut the mortality rate of the illness by half. During the spring and summer flu waves, approximately half of H1N1 patients received the medication, but the rate fell to approximately nine percent during the fall wave, according to CIDRAP News.

The report, conducted by a U.S.-Mexican team and published in the journal BMC Infectious Diseases, also showed that delays in hospitalization increased the risk of death by close to three times.

"Overall, our findings suggest that higher rates of timely antiviral treatment during the 2009 fall pandemic wave in Mexico could have led to a substantially lower death toll," the researchers said, CIDRAP News reports.

The investigators suggest that changes in the perceived threat of the epidemic most likely help to explain the drop in antiviral use. Early data suggested that impact of H1N1 would be unusually severe.

"By the end of the summer 2009 pandemic wave, it became clear that the severity of the 2009 pandemic virus was comparable to that of contemporaneous seasonal influenza epidemics," the report said, CIDRAP News reports.