Williams SP, et al. - Researchers sought to assess sexually transmitted infection (STI) prevalence among homeless adults via systematically searching 3 databases and reviewing the 2000–2016 literature on STI prevalence among homeless adults in the United States. Homeless adults were identified to be a vulnerable population. Higher STI prevalence was observed in association with intimate partner violence, injection and noninjection substance use, incarceration history, and homelessness severity. These factors were noted to have a concurrent association with housing instability and homelessness severity. They suggest integrating sexual health and other health services where homeless adults seek or receive housing and other support services to enhance addressing STI prevention needs of homeless adults.