Update: Sexually transmitted infections, active component, U.S. Armed Forces, 2013-2021.

This report summarizes incidence rates of the 5 most common sexually transmitted infections (STIs) among active component service members of the U.S. Armed Forces during 2013-2021. Infections with chlamydia were the most common, followed in decreasing order of frequency by infections with genital human papillomavirus (HPV), gonorrhea, genital herpes simplex virus (HSV), and syphilis. Compared to men, women had higher rates of all STIs except for syphilis. In general, compared to their respective counterparts, younger service members, non-Hispanic Black service members, those who were single and other/unknown marital status, and enlisted service members had higher incidence rates of STIs. Although rates of chlamydia and gonorrhea increased among both male and female service members during the latter half of the surveillance period, there was a notable decrease in the rates of chlamydia in both sexes from 2019 through 2021, and the rates of gonorrhea decreased slightly for both men and women during 2018-2021. Rates of syphilis generally increased during the first half of the surveillance period, decreased in 2020, then increased in 2021. Rates of genital HSV declined during the period from 2016 through 2021 for both male and female service members. The rates of genital HPV decreased steadily between 2012 and 2021 in men and declined between 2015 and 2021 among women. Similarities to and differences from the findings of the last MSMR update on STIs are discussed.