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HIV Transmission Prevention: Information for Health Care Providers

Health care providers who treat patients with HIV have an important role in supporting HIV prevention. Because a patient’s needs may change over time, health care providers should engage patients in brief conversations at every visit to discuss the prevention steps the patient is taking. Below is information about different HIV prevention methods, including treatment as prevention, PrEP, PEP, and condom use, as well as suggested questions that providers can use to start the conversation with their patients.

Treatment as Prevention

Taking ART to achieve and maintain an undetectable viral load enables patients with HIV to stay healthy. It also helps prevent transmission to others, which is known as treatment as prevention. This method is extremely effective for preventing sexual transmission of HIV and more research is needed to understand how well it prevents transmission by other routes.

Sexual Transmission

People with HIV who take ART as prescribed and achieve and maintain an undetectable viral load have effectively no risk of transmitting HIV through sex.

Three recent landmark studies – the HPTN 052, PARTNER, and Opposites Attract studies – have shown the strongest evidence to date that treatment prevents sexual transmission of HIV.1-4 Across all three studies, there were no linked HIV transmissions observed between mixed-HIV-status partners when the partner with HIV was virally suppressed (defined in these studies as having a plasma HIV RNA viral load less than either 200 or 400 copies/mL).

In 2011, interim results from the HPTN052 clinical trial demonstrated a significant reduction in HIV transmission risk among mixed-HIV-status heterosexual couples who started ART versus those who delayed.1 Subsequent analyses from HPTN052, focusing on viral suppression, reported no linked HIV transmissions among these couples when the person with HIV was virally suppressed (defined as having less than 400 copies/mL).2 In the PARTNER and Opposites Attract studies, both heterosexual and male-male mixed-HIV-status couples engaged in sex without condoms or pre-exposure prophylaxis (PrEP) while the person with HIV was virally suppressed (defined in these cases has having less than 200 copies/mL, although most were undetectable). These two studies quantified the extent of sexual exposure, which included more than 74,000 episodes of condomless anal or vaginal intercourse during approximately 1,500 couple-years of observation. During this time, no linked transmission were observed. When CDC combined the results from these two studies, the estimated combined HIV transmission risk estimate while virally suppressed is 0.0 (0.0 – 0.25) per 100 couple years, with an upper confidence limit of 0.25% per year.5 Although the remote possibility of a transmission cannot be ruled out entirely, no linked transmissions were observed across both studies.

This means that there is effectively no risk of sexual transmission among mixed-HIV-status couples when the partner with HIV achieves and maintains viral suppression.

While treatment as prevention is a highly effective prevention strategy, its success depends on achieving and maintaining an undetectable viral load. If the patient’s viral load increases, so does their risk of transmitting HIV to their sex partners. For patients who rely on treatment and viral suppression as a prevention strategy, it is not known if viral load testing should be conducted more frequently than currently recommended for treatment.

People with HIV who use or want to use ART as their primary means of prevention may benefit from additional prevention methods if either partner desires added security for HIV protection or is concerned about STDs (e.g., PrEP and/or condoms). Using multiple HIV prevention methods is especially important if the person with HIV has trouble with adherence or has not achieved or maintained viral suppression.

Conversations about Treatment as Prevention for Sexual Transmission

Educating patients about the value of treatment as prevention can help them manage their HIV. Engaging patients in routine, brief conversations about treatment as prevention can also help health care providers become more familiar with each patient, including their adherence and transmission risk. In addition, these conversations can normalize discussions about factors that have an effect on their health, such as sex, substance use, and mental health disorders.

It may be helpful to share information about the research then ask open-ended questions to start the conversation. Here are some examples:

  • “Studies have followed mixed-HIV-status couples who engaged in thousands of unprotected sex acts while the partner with HIV was suppressed on ART. Not a single HIV-negative person got HIV from their sexual partner with an undetectable viral load. What does this information mean to you?”
  • “You have to both achieve and then maintain an undetectable viral load to maximally reduce any risk of sexually transmitting HIV – how do you feel about that?”
  • “Your viral load continues to be undetectable, which is great! Can you tell me the methods you are using to prevent other STDs?”

Once the conversation has started, health care providers can use the information shared with them to identify barriers to ART adherence and regular, ongoing care that may make it difficult to achieve and maintain viral suppression.

Perinatal Transmission including Breast Feeding

Advances in HIV research, prevention, and treatment have made it possible for many women living with HIV to give birth without transmitting the virus to their babies. The annual number of HIV infections through perinatal, or mother-to-child, transmission has declined by more than 90% since the early 1990s.6

Studies have found that if a pregnant person takes ART as prescribed for viral suppression throughout pregnancy, labor, and delivery, and the baby is then given ART for 4-6 weeks after delivery and is not breastfed, the risk of transmitting HIV to the baby can be 1% or less.7 Furthermore, this risk decreases if the mother started taking ART early in pregnancy, and is effectively zero if the mother starts ART prior to conception and maintains an undetectable viral load throughout pregnancy.7

Mothers who achieve and maintain viral suppression substantially reduce the risk of transmitting HIV to their infants through breastfeeding; however, data are at present insufficient to recommend maternal treatment alone to prevent mother-to-child transmission through breast milk. Current recommendations in the United States are for mothers living with HIV to abstain from breastfeeding their infants.

The National Perinatal HIV Hotline (888-448-8765) provides free clinical consultation on all aspects of perinatal HIV care.

Injection Drug Use Transmission

There are insufficient data to estimate the impact of viral suppression on HIV transmission through sharing needles or other injection drug equipment, but studies indicate there may be some risk reduction.

Pre-Exposure Prophylaxis (PrEP) and Post-Exposure Prophylaxis (PEP)

To prevent HIV acquisition, both PrEP and PEP may be appropriate for sex and injection drug partners of people with HIV.

PrEP is a prevention method used by people who are HIV-negative and at high risk for being exposed to HIV through sexual contact or injection drug use. At present, the only FDA-approved medication for PrEP is oral tenofovir disoproxil fumarate and emtricitabine (TDF-FTC), which is available as a fixed-dose combination in a tablet called Truvada®. When someone is exposed to HIV through sex or injection drug use, these medicines can work to keep the virus from establishing an infection. PrEP guidelines state that people taking PrEP should commit to taking the drug every day and seeing their health care provider for follow-up every 3 months. Some patients may ask about event-based dosing of PrEP, which may be discussed in some patient groups. At this time, PrEP guidelines do not recommend event-based dosing.

PEP refers to the use of antiretroviral drugs for people who are HIV-negative after a single high-risk exposure to stop HIV infection. PEP must be started as soon as possible to be effective – always within 72 hours of a possible exposure – and continued for 4 weeks. PEP is recommended for potential exposures through sexual contact or injection drug use. PEP should be provided only for infrequent exposures. Patients who engage in behaviors that result in frequent, recurrent exposures should consider PrEP.

Sexual Transmission

Studies have shown that PrEP can reduce the risk of HIV infection in people who are at high risk by about 99%.8,9  PrEP may also be useful in mixed-HIV-status couples who want to conceive.10

Injection Drug Use Transmission

Among people who inject drugs, PrEP reduces the risk of getting HIV by at least 74% when taken daily.

There are insufficient data about PEP’s effectiveness to prevent HIV infections from nonsterile injection drug use. PEP has shown to reduce HIV acquisition from occupational sharps exposure in health care settings. Notably, occupational exposures tend to be single events. For persons who inject drugs and experience many exposures, PrEP and not PEP is likely be a better prevention strategy.

Conversations about PrEP and PEP

For patients with HIV, sharing information about PrEP and PEP for their sex and drug injection partners without HIV can help prevent transmission. Health care providers can also offer to facilitate the conversations or identify providers who may be able to offer PrEP and PEP to partners.

  • “What do you do when a condom breaks?”
  • “What do you find works or doesn’t work when you talk with partners about HIV prevention medicines, like PrEP, they could take?”
  • “When you party, are you injecting drugs? If so, are you sharing needles or drug preparation equipment with anyone?”

Health care providers can encourage conversations between partners by asking patients living with HIV, “How do you talk with your sex partners about viral suppression and sexual transmission?” They can also offer to facilitate the conversations or identify providers who may be able to offer PrEP and PEP to partners.

Condom Use

Correctly using male condoms and other barriers like female condoms and dental dams can reduce the risk of STDs, including HIV. To achieve the maximum protective effect, condoms must be used consistently and correctly throughout the entire sex act, from start (of sexual contact) to finish (after ejaculation).

Health care providers can share information with patients about proper use of male condoms, female condoms, and dental dams.

Conversations about Condom Use

  • “It is important to use condoms to protect yourself from STDs such as syphilis or gonorrhea. What do you know about STDs?”
  • “What are some benefits to using condoms at this point, given your viral load is undetectable?”
  • “How frequently are you using condoms and for what types of sex?”

Multiple Prevention Options

With multiple HIV prevention options available, everyone with or without HIV who has sex or injects drugs should learn about all their options and use the prevention strategies that work for them. Using multiple prevention methods can provide added protective benefits, as well as added peace of mind for both partners.

Note for Conception

Mixed-HIV-status couples who are planning to conceive may consider the following:

  • Treatment as prevention
  • Limiting condomless sex to the time of ovulation
  • Using PrEP
  • Semen processing prior to insemination or fertilization, especially when fertility treatment is needed


The HIV Risk Reduction Tool can be customized to any individual and provides information to educate them about the relative HIV transmission risk of different behaviors. Health care providers can walk through this online tool with their patients during office visits, or they can refer patients to it to explore on their own or with other staff.

Treatment as Prevention

HIV Treatment as Prevention
Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents

PrEP and PEP

Prevention with Partners of Persons with HIV

Condom Use

2015 Sexually Transmitted Diseases Treatment Guidelines


  1. Cohen MS, Chen YQ, McCauley M, et al. Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med. Aug 11 2011;365(6):493-505. PubMed abstract.
  2. Cohen MS, Chen YQ, McCauley M, et al. Antiretroviral therapy for the prevention of HIV-1 transmission. N Engl J Med. 2016;375:830-9. PubMed abstract.
  3. Rodger AJ, Cambiano V, Bruun T, et al. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy. JAMA 2016;316(2):171-81. PubMed abstract.
  4. Bavinton B, Grinsztejh B, Phanuphak N, et al. HIV treatment prevents HIV transmission in male serodiscordant couples in Australia, Thailand and Brazil. Presented at the 9th IAS Conference on HIV Science (IAS 2017), Paris, France; July 25, 2017.
  5. CDC. Evidence of HIV Treatment and Viral Suppression in Preventing the Sexual Transmission of HIV. 2017.
  6. CDC. Achievements in Public Health: Reduction in Perinatal Transmission of HIV Infection — United States, 1985—2005. MMWR 2006. 55(21);592-597.
  7. Townsend, Claire L; Cortina-Borja, et al. Low rates of mother-to-child transmission of HIV following effective pregnancy interventions in the United Kingdom and Ireland, 2000–2006. AIDS. 2008. 22(8):973-981. PubMed abstract.
  8. Grant RM, Lama JR, Anderson PL, et al. Pre-exposure chemoprophylaxis for HIV prevention in men who have sex with men. N Eng J Med. 2010;363(27):2587-99. PubMed abstract.
  9. Baeten JM, Donnell D, Ndase P, et al. Antiretroviral prophylaxis for HIV prevention in heterosexual men and women. N Engl J Med. 2012;367(5):399-410. PubMed abstract.
  10. CDC. Provider Information Sheet – PrEP During Conception, Pregnancy, and Breastfeeding.
  11. Choopanya K, Martin M, Suntharasamai P, et al. Antiretroviral prophylaxis for HIV infection in injecting drug users in Bangkok, Thailand (the Bangkok Tenofovir Study): a randomised, double-blind, placebo-controlled phase 3 trial. Lancet 2013;381(9883): 2083-90. PubMed abstract.