Men who have sex with men at high risk of HIV infection can significantly lower their infection risk by taking pre-exposure prophylaxis from designated HIV clinics on schedule

Cost: This is a prescription medication, so in most places it must be paid for out of pocket. Prices range from several hundred to several thousand yuan. Before prescribing it, doctors must test for HIV, kidney function, and hepatitis B. Follow-up tests are required every three months. The main challenge is remembering to take the pills every day without fail.

In plain terms: People who aren’t yet infected can take an antiviral drug called pre-exposure prophylaxis to protect themselves. Those who take it consistently cut their risk of infection by more than 70%. On the other hand, people who take it intermittently see almost no benefit. Because it’s a prescription drug, a medical checkup is mandatory before obtaining it, and regular follow-ups are necessary thereafter.

Benefit: This medication is a fixed-dose combination of emtricitabine and tenofovir. In the iPrEx trial, 2,499 men who have sex with men and transgender women were assigned to either take this drug daily or receive a placebo. The group taking the medication saw a 44% reduction in infections (95% CI 15–63). Among participants whose blood tests confirmed they were taking the drug, the protective effect was even stronger. The UK’s PROUD trial involved 544 men who have sex with men; those who started treatment immediately had an 86% lower infection rate compared to those who delayed treatment for a year (90% CI 64–96). France’s IPERGAY trial evaluated on-demand dosing before and after sex; results showed an 86% drop in infections (95% CI 40–98). A meta-analysis compiled by WHO concluded that overall, the relative risk of infection dropped to 0.49 (0.33–0.73, roughly a 51% reduction). In trials where adherence exceeded 70%, the relative risk fell to 0.30 (0.21–0.45, about a 70% reduction); when adherence stayed below 40%, the relative risk was 0.95, essentially indicating no effect. In August 2020, China’s National Medical Products Administration approved this drug for pre-exposure prophylaxis use in adults and adolescents weighing at least 35 kg (both domestically and internationally).

Evidence grade: A

Sources:Grant RM, Lama JR, Anderson PL, et al. (2010). Preexposure chemoprophylaxis for HIV prevention in men who have sex with men. New England Journal of Medicine, 363(27), 2587–2599. https://doi.org/10.1056/NEJMoa1011205；McCormack S, Dunn DT, Desai M, et al. (2016). Pre-exposure prophylaxis to prevent the acquisition of HIV-1 infection (PROUD): effectiveness results from the pilot phase of a pragmatic open-label randomised trial. The Lancet, 387(10013), 53–60. https://doi.org/10.1016/S0140-6736(15)00056-2；Molina JM, Capitant C, Spire B, et al. (2015). On-demand preexposure prophylaxis in men at high risk for HIV-1 infection. New England Journal of Medicine, 373(23), 2237–2246. https://doi.org/10.1056/NEJMoa1506273；Fonner VA, Dalglish SL, Kennedy CE, et al. (2016). Effectiveness and safety of oral HIV preexposure prophylaxis for all populations. AIDS, 30(12), 1973–1983. https://doi.org/10.1097/QAD.0000000000001145；Xu JJ, Huang XJ, Liu XC, et al. (2020). Consensus statement on human immunodeficiency virus pre-exposure prophylaxis in China. Chinese Medical Journal, 133(23), 2840–2846. https://doi.org/10.1097/CM9.0000000000001181（中文版《中国 HIV 暴露前预防用药专家共识》）；World Health Organization (2019). What's the 2+1+1? Event-driven oral pre-exposure prophylaxis to prevent HIV for men who have sex with men (WHO/CDS/HIV/19.8). https://www.who.int/publications/i/item/what-s-the-2-1-1-event-driven-oral-pre-exposure-prophylaxis-to-prevent-hiv-for-men-who-have-sex-with-men；国务院办公厅 (2024). 中国遏制与防治艾滋病规划（2024—2030 年）. https://www.gov.cn/zhengce/zhengceku/202412/content_6992033.htm

Notes: The participants in these trials were primarily men who have sex with men; therefore, they are the group most encouraged to seek this treatment. Others at high risk of infection can also consult doctors to determine suitability. Prior to prescribing, it is essential to confirm that patients are not already infected; taking the medication while infected can foster viral resistance. Self-test results cannot be used as a basis for prescription. For individuals with hepatitis B, discontinuing treatment may trigger a flare-up, so testing is mandatory beforehand. WHO currently recommends on-demand dosing only for men who have sex with men engaging in sex fewer than twice a week; the regimen involves taking two tablets 2–24 hours prior to sex, followed by one tablet 24 and 48 hours afterward. Women and hepatitis B carriers must adhere to daily dosing. Trials involving on-demand dosing reported more gastrointestinal and kidney-related side effects than placebo groups; hence, regular medical checkups are indispensable. Since 2019, China has been piloting this program among men who have sex with men; official plans for 2024 emphasize “standardized implementation.” No nationwide free distribution program has been confirmed. Prospective patients should call local disease control centers to identify designated HIV clinics or STD/AIDS outpatient departments offering this treatment. Importantly, this medication does not protect against sexually transmitted infections such as syphilis or gonorrhea; condoms must still be used consistently, as noted in Section 30 of this chapter. In cases where exposure has already occurred, emergency post-exposure prophylaxis is available per Section 13, Item 38 (within 72 hours). Ultimately, this treatment safeguards both the individual and their sexual partners.