When it comes to HIV prevention, there are several interventions to reduce HIV transmission, some of which are highly effective. As a provider or member of the HIV workforce, you can help guide and teach individuals, both negative and positive, about current HIV prevention methods. HIV transmission risk is further decreased when multiple methods are used in conjunction with one another.
Currently, aside from safer sex (such as using condoms), pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP) are the most widely used and effective HIV prevention methods. PrEP is prescribed to HIV-negative individuals as a pill taken once a day. PrEP is also has effective when taken "on demand," before and after sex, as shown in the IPERGAY study. TasP is also effective because when a person with HIV is on treatment and has an undetectable viral load, their chances of transmitting HIV are virtually eliminated, as shown in the PARTNER study and the HPTN 052 study. In other words, "undetectable = untransmittable."
Other prevention methods, some of which are still only in the research phase, include the following:
Male circumcision, or voluntary medical male circumcision (VMMC), protects men against HIV transmission by safely removing the foreskin. In 2006, two large studies were ended early after they both showed that HIV transmission was reduced by around 50% for men who were circumcised. A follow-up study found that the risk reduction could be as much as 61%. Both the World Health Organization and UNAIDS recommend VMMC for HIV prevention.
HIV vaccines or, more specifically, the research and development of an effective HIV vaccine continues to this day. After years of vaccine candidates showing no success, in 2009 we saw results from RV144, also known as the Thai prime-boost AIDS vaccine trial, which showed 31% efficacy for its vaccine candidate to protect against HIV transmission. And in 2016, another large HIV vaccine efficacy trial, known as HVTN 702, began.
Microbicides, which usually come in gel form, are inserted into the vagina or rectum either daily or before and after sex. They usually contain an antiretroviral, such as tenofovir (Viread), and act as a form of topical PrEP. They have shown little success in studies such as the VOICE and the FACTS studies. However, the adherence levels in these studies were notably low, suggesting that, while the gels themselves work, in real-life practice, people did not want to use them.
Preventing mother-to-child transmission (PMTCT), or the prevention of perinatal HIV transmission, refers to ways to stop the transmission of HIV from mother to child, whether during pregnancy, giving birth or breastfeeding. This usually involves putting the mother on antiretroviral therapy, which can also virtually eliminate the transmission risk from breast milk.
Post-exposure prophylaxis (PEP) is the administration of antiretroviral drugs after potential exposure to HIV. PEP is usually given only in emergencies and must be started within 72 hours to be effective.
Vaginal rings are currently being studied for HIV prevention in women. They are made out of silicone and inserted into the vagina, where they slowly release antiretrovirals for protection against HIV. Initial studies have shown a lot of promise and effectiveness.
Needle exchange programs for people who inject drugs are very important for preventing HIV transmission that can occur when individuals share syringes.
Warren Tong is the senior science editor for TheBody.com and TheBodyPRO.com.
Follow Warren on Twitter: @WarrenAtTheBody.