High-dose influenza vaccine was more effective at preventing post-influenza deaths among elderly individuals during the 2012-2013 influenza season than standard-dose vaccines-- when the A(H3N2) influenza viruses were broadly circulating-- according to a study done by researchers at the U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention and the Centers for Medicare and Medicaid Services.
Specifically, people who received the high-dose influenza vaccine during the 2012-2013 influenza season were 36.4% less likely to die in the 30 days following hospitalization or an emergency department visit that included an influenza diagnosis compared to the standard-dose vaccine. During the following season (2013-2014), when H1N1 viruses dominated and the standard-dose vaccine had better effectiveness than the previous season, the high-dose vaccine was not significantly better at preventing deaths among the Medicare patients studied.
The findings suggest that the high-dose influenza vaccine offers greater benefit to older adults than do standard-dose vaccines when A(H3N2) influenza viruses are widely circulating.
The study findings are important because the goal of expanding immunization programs in the US has been largely based on trying to reduce serious complications of influenza infections, including death. This is especially important in older persons who have long been recognized as being at greatest risk for severe influenza outcomes. Therefore, the availability and use of vaccines that provide better protection against H3N2 influenza viruses for older adults could significantly reduce influenza-associated morbidity and mortality.
The individuals in the current study were Medicare beneficiaries age 65 years or older, who were enrolled in fee-for-service care through Medicare parts A and B, and who were not disabled or suffering from end-stage renal disease. In addition, only those beneficiaries who received inactivated influenza vaccines at a community-located pharmacy were included in the study. (Inactivated vaccines contain inactivated or “dead” virus and therefore cannot cause infection in a vaccinated person.) This restricted participants in the study to those who met a minimum standard of physical and mental health, i.e., the ability to visit a pharmacy and request influenza vaccination.
Individuals receiving high-dose or standard-dose vaccines were similar regarding health conditions and certain other characteristics.
In a previous study of older adults enrolled in Medicare who were vaccinated during the 2012–2013 influenza season with high-dose vs standard-dose vaccines in pharmacies, the high-dose vaccine was 22% more effective than the standard-dose vaccine in preventing influenza infections and 22% more effective in preventing influenza hospital admissions.
Comparative Effectiveness of High-Dose Versus Standard-Dose Influenza Vaccines Among US Medicare Beneficiaries in Preventing Postinfluenza Deaths During 2012–2013 and 2013–2014
J Infect Dis
Published: 02 March 2017
David K. Shay,1 Yoganand Chillarige,2 Jeffrey Kelman,3 Richard A. Forshee,4 Ivo M. Foppa,1,5 Michael Wernecke,2 Yun Lu,4 Jill M. Ferdinands,1 Arjun Iyengar,2 Alicia M. Fry,1 Chris Worrall,3 and Hector S. Izurieta4,6
1Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia; 2Acumen LLC, Burlingame, California; 3Centers for Medicare and Medicaid Services, Washington, District of Columbia; 4Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland; 5Battelle Memorial Institute, Atlanta, Georgia; and 6Department of Health Sciences, Universidad Rey Juan Carlos, Madrid, Spain