Influenza-associated mortality for different causes of death during the 2010-2011 through the 2014-2015 influenza seasons in Russia

Résumé : Background: There is limited information on the volume of influenza-associated mortality in Russia. Methods: Using previously developed methodology (Goldstein et al., Epidemiology 2012), we regressed the monthly rates of mortality for respiratory causes, circulatory causes, and for certain infectious and parasitic diseases (available from the Russian Federal State Statistics Service (Rosstat)) linearly against the monthly proxies for the incidence of influenza A/H3N2, A/H1N1 and B (obtained using data from the Smorodintsev Research Institute of Influenza (RII) on levels of ILI/ARI consultations and the percent of respiratory specimens testing positive for influenza A/H3N2, A/H1N1 and B), adjusting for the baseline rates of mortality not associated with influenza circulation and temporal trends. Results: For the 2010/11 through the 2014/15 seasons, influenza circulation was associated with an average annual 11106 (95% CI (4321,17892)) deaths for circulatory causes, 4552 (3744,5360) deaths for respiratory causes, and 343 (63,624) deaths for certain infectious and parasitic diseases, with influenza A/H3N2 being responsible for the majority of influenza-associated respiratory deaths and influenza B making a substantial contribution to influenza-associated mortality for circulatory causes. Conclusions: Influenza circulation is associated with a substantial mortality burden in Russia, particularly for circulatory deaths. Those results support the potential utility of influenza vaccination (with the role played by influenza B in circulatory mortality pointing to the benefit of quadrivalent influenza vaccines), as well as of administration of antiviral drugs for high-risk individuals during periods of active influenza circulation.