文档介绍：HIV感染的预防
4个环节
行为学 (如：正确的避孕套的应用，更少的性伴)，生物学 (如：包皮环切术）
性交前和性交过程干预：疫苗，暴露前的药物应用(ARV PrEP）
暴露后疫苗的应用及暴露后药物预防 (ARV PEP）
治疗即预防：对感染者有效的抗病毒治疗可以降低他们传播给同伴的风险
HIV 的传播
HIV的感染性依赖于HIV+者体液（血液、***分泌物或精子）的病毒和病毒本身的 (遗传表型)：
体液中的高病毒载量有较高的感染风险
病毒亚型影响HIV的获得风险：如 clade C 比B更有感染性
Test and treat Models
Many models of the effect(s) of HIV therapy on the spread of disease have been generated, with very mixed predictions (Table 3). 
Researchers at the WHO offered optimistic models that helped stimulate a stronger belief that treatment will serve as prevention (see figure 6, next page).
Based on some ecological studies (from Canada and the USA), investigators have argued that a falling number of patients with newly diagnosed HIV in recent years reflects the effects of ART in the community. In addition, further evidence for the population level benefit of ART has come from the AFRICA CENTRE in Kawazu Natal. Investigators looking at data in areas where antiretroviral therapy uptake is high (greater than 30%) people were 40% less likely to acquire HIV than in areas where HIV uptake was low (less than 10%).
Test and treat
The ‘Test and Treat’ strategy is also based on the observation that people with very low VLs are less likely to transmit the virus than those with higher VLs. This idea was confirmed by a large multi national trial, HPTN 052, which demonstrated that efffective treatment of HOV reduced HIV transmission to a heterosexual partner by 96%. HIV infected people treated at high CD4 count (median 446 cell/cubic mm) also had improved health outcomes. This result was named “Breathrough of the Year” by Science Magazine in 2011.
暴露后预防（ Post-Exsposure Prophylaxis, PEP）
暴露前预防（preexposure prophylaxis ，PrEP）
MSM
Heterosexual Men and Women
IDU