Measles, mumps, rubella and varicella among service members and other beneficiaries of the Military Health System, 2019-2024.

Measles, mumps, rubella, and varicella (MMR/V) cases have decreased in the U.S. Military Health System (MHS) overall, but in recent years, increasing numbers of MMR/V outbreaks in the U.S. have led to a rise in reported cases among the civilian population. Data were queried from the Defense Medical Surveillance System to identify total number of confirmed and possible MMR/V cases among all MHS beneficiaries from 2019 through 2024. The total numbers of confirmed and possible cases among MHS beneficiaries included 8 confirmed and 71 possible cases of measles, 18 confirmed and 193 possible cases of mumps, 13 confirmed and 265 possible cases of rubella, and 251 confirmed and 4,554 possible cases of varicella. During the surveillance period the numbers of all confirmed and possible cases decreased. Among service members, most cases were either partially vaccinated, or vaccination records were not available. In this 6-year surveillance period, cases of MMR/V decreased over time. No cases of measles were observed among U.S. service members during the surveillance period. This report emphasizes the importance of continued vaccination against MMR/V to limit morbidity among U.S. service members, as evidenced by the lower number of cases among service members, who are required to be vaccinated, when compared to non-service members.