Influenza in the US Military: An Overview

Circulation of influenza strains in the military has been responsible for clusters of illness among military personnel in the United States and remote areas where they operate, although not usually associated with a high degree of morbidity [1,2]. During the latest 5-year period (2007-2012) for which there is published data by the AFHSC, influenza was found to be responsible for as many as 7,000 to 25,000 cases per week in the MHS, of which 3,000 to 16,000 (40 to 65 percent) involved military personnel [3]. Since 2009, pH1N1 has continued to circulate worldwide; [4] it resurged in the US from November 2013 through February 2014, causing an increase in laboratory-confirmed influenza associated hospitalizations in all age groups [5]. Since summer-fall of 2014, drifted H3N2 viruses have begun to predominate causing an increase in laboratory-confirmed influenza associated hospitalizations among both US civilian and military personnel in the winter of 2014-2015 and through December 2015 [1,6]. These drifted H3N2 viruses have also been associated with increased mortality, especially among those older than 64 years [7-9].