For men who have sex with men (MSM) engaging in high-risk sexual behavior, asking for Pre-Exposure Prophylaxis (PrEP) at designated HIV hospitals and taking it on schedule can reduce infection risk by over 70%

This is a prescription drug, and in most places, it is out-of-pocket, with prices ranging from several hundred to several thousand yuan. Before prescribing, tests for HIV, kidney function, and Hepatitis B are required. After that, follow-up checkups are needed every 3 months. The difficulty lies in taking it on time every single day.

This medication is a combination tablet of emtricitabine and tenofovir. The iPrEx trial involved 2499 men who have sex with men and transgender women taking either the medication or a placebo daily. The medication group had 44% fewer infections (95% CI 15–63). Protection was much stronger in individuals with detectable drug levels in their blood. The UK's PROUD trial included 544 men who have sex with men. The group that started medication immediately had 86% fewer infections than the group that delayed for one year (90% CI 64–96, 90% credible interval). The French IPERGAY trial, involving on-demand dosing before and after sexual activity, showed 86% fewer infections (95% CI 40–98). A meta-analysis used by the World Health Organization combined various trials. Overall RR 0.49 (0.33–0.73, reduced by approximately 51%). For trials with a medication rate exceeding 70%, RR 0.30 (0.21–0.45, reduced by approximately 70%). For those with a medication rate of less than 40%, RR 0.95, essentially ineffective. The National Medical Products Administration (NMPA) approved this drug for pre-exposure prophylaxis in 2020 year 8 month. It can be used for adults and adolescents weighing at least 35 kg (multiple countries / China)

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

The participants in the trial were primarily men who have sex with men (MSM), so this is the group that should most definitely consult a professional. Other individuals engaging in high-risk sexual behavior can also consult a doctor regarding suitability. Before prescribing, it must be confirmed that there is no existing infection; taking it while already infected can lead to viral drug resistance, and the results of self-test kits cannot be used as a definitive basis. For those with Hepatitis B, stopping the medication may trigger a hepatitis flare-up, so testing is required before prescription. The World Health Organization only recommends on-demand dosing for men who have sex with men, suitable for those with fewer than 2 sexual encounters per week on average. The dosing regimen is to take 2 tablet(s) 2 to 24 hours before sexual activity, followed by 1 tablet(s) after 24 hours and 1 tablet(s) after 48 hours. Women and individuals with Hepatitis B must take it daily. In the on-demand dosing trials, the medication group experienced more gastrointestinal and renal adverse reactions than the placebo group, so follow-up examinations cannot be skipped. A pilot program has been underway among men who have sex with men in China since 2019, and the 2024 year plan specifies "standardized implementation." No nationwide free policy was found. You can obtain it at the infectious disease department or the STD/AIDS clinic of a local designated AIDS hospital; call your local CDC first to ask which hospital provides it. It does not protect against STDs such as syphilis or gonorrhea, so condoms must still be used, as seen in section 30 of this chapter (use condoms throughout sexual activity). If high-risk behavior has already occurred, see section 13, clause 38, for remedial measures (72 hours to obtain PEP medication). The primary beneficiary is yourself, and it also protects your partner.