History and Prevention of STIs
Asking patients about prior STIs can provide information about the potential risk for HIV as well as risk for acquiring other STIs, such as gonorrhea, chlamydia, syphilis, or viral hepatitis. Clinicians should enquire about methods individuals use to prevent STIs, which may include condoms, other barrier methods, serosorting (a practice of having sex with persons of the same HIV status),10 or sexual positioning (being primarily the insertive partner or the receptive partner).4 Receptive anal intercourse has been associated with a higher probability of HIV infection compared with insertive anal intercourse (138/10,000 exposures vs 11/10,000 exposures, respectively).11
Condoms play a significant role in HIV and STI prevention. Condoms have been shown to reduce HIV infection by approximately 70% in MSM.12 The female condom can also be used by MSM as an alternative barrier method for receptive anal intercourse.4
Some MSM may also have sex with persons of childbearing potential. Clinicians should enquire about plans for pregnancy and need for contraception, if desired.
Role of STIs and HIV risk
Having an STI, such as gonorrhea, chlamydia, or syphilis, has been associated with increased risk of acquiring HIV in MSM.13 Sexually active MSM should be screened for STIs at least annually or more frequently based on risk.4 When screening for STIs, it is important for clinicians to remember that many oropharyngeal and rectal infections may be asymptomatic. Screening only for urethral gonococcal or chlamydial infection may miss asymptomatic infection in MSM.14 Therefore, clinicians should screen for oral and rectal STIs with the use of nucleic acid amplification testing (NAAT).4
In 2019, the US Food and Drug Administration (FDA) approved NAAT for diagnosis of pharyngeal and rectal gonococcal and chlamydial infection.15 To obtain an oral NAAT specimen, clinicians can use a standard NAAT collection kit and swab the posterior pharynx, similar to the method employed for obtaining a strep culture. Obtaining a rectal NAAT specimen involves insertion of the collection swab gently into the anal canal slightly past the anal sphincter and rotating the swab for 5 to 10 seconds while the patient is in either a standing or lateral position.16 Lubricant should not be used as it can alter analysis of the specimen. Patients may also be instructed on self-collection of these specimens. Self-collection has been shown to be an effective method of obtaining specimens and can provide patients with greater privacy, if desired.17 Each specimen must be labelled according to the site of collection. Urine NAAT testing is appropriate for urethral STIs.4
Syphilis has been associated with an increased risk for future acquisition of HIV.13 Rates of syphilis among MSM have increased in the past several years.18 Testing for syphilis can be done via nontreponemal specific tests (eg, rapid plasma reagin [RPR]) or fluorescent treponemal antibody (FTA)-specific tests.19 It is important for clinicians to remember that the FTA test will always be reactive in persons who have had syphilis previously. Screening for syphilis in sexually active MSM should be performed at least annually and more frequently based on reported risk.4
Sexually acquired hepatitis C virus (HCV) infection is seen more frequently among MSM, particularly among those living with HIV.20 Although HCV infection may be asymptomatic, clinicians should consider acute HCV infection in persons presenting with unexplained transaminitis, jaundice, or other signs and symptoms of hepatitis. The American Association for the Study of Liver Disease recommends baseline HCV testing in persons on PrEP and counseling all MSM about the risk of sexual HCV transmission with high-risk sexual and drug use practices.20 Vaccination should be offered to individuals not immune to hepatitis A or B virus.
In 2019, the US Preventive Services Task Force recommended PrEP as a grade A recommendation for persons at high risk of acquiring HIV (Table 1).21,22 PrEP is an intervention that provides protection against HIV through the use of antiretroviral agents that are taken prior to sexual or drug-using encounters. In 2012, the FDA approved tenofovir disoproxil fumarate (TDF) in combination with emtricitabine (FTC) (Truvada®, Gilead Sciences) as the first oral agent for PrEP.23 Studies of Truvada in various populations (MSM, heterosexuals, and persons who inject drugs) have demonstrated efficacy in reducing HIV infection. The CDC has reported that the use of daily PrEP has been shown to be more than 99% effective in preventing HIV infection.24
In October 2019, the FDA approved a second PrEP option: tenofovir alafenamide (TAF)/FTC (Descovy®, Gilead Sciences).25 These 2 formulations are the only drug combinations approved for PrEP in MSM. Both formulations are HIV nucleoside reverse transcriptase inhibitors. The major difference between TDF/FTC and TAF/FTC is that TAF/FTC has been shown to have less effect on renal function and bone mineral density compared with TDF/FTC.26 Both medications are taken as one pill once daily (Table 2).27,28