Measles, mumps, rubella, and varicella among service members and other beneficiaries of the military health system, 1 January 2016–30 June 2019

Measles, mumps, rubella, and varicella (MMR/V) are highly communicable infectious diseases whose causative agents are spread through contact with contaminated surfaces or airborne droplets. Individuals at highest risk for MMR/V infections include infants; unvaccinated or inadequately vaccinated persons; individuals living in communities with low vaccination rates or in crowded, unsanitary conditions; and persons with compromised immune sys-tems. Between 1 January 2016 and 30 June 2019, there were 5 confirmed measles cases and 64 confirmed mumps cases among all Military Health System (MHS) beneficiaries. During this period, no cases of measles were reported among U.S. service members. There were 29 confirmed mumps cases among service members during the surveillance period; 2 cases occurred in 2016, 17 in 2017, 5 in 2018, and 5 in the first 6 months of 2019. There were 6 confirmed rubella cases among all MHS beneficiaries. Among service members, there were 39 confirmed cases of varicella during the surveillance period; 9 cases occurred in 2016, 11 in 2017, 11 in 2018, and 8 in the first 6 months of 2019. Recent trends in MMR/V in both military and civilian populations in the U.S. highlight the importance of primary and booster vaccinations.