HIV: Preventing Transmission

Medically Reviewed by Jonathan E. Kaplan, MD on May 21, 2023
4 min read

If you have HIV, there are ways you can protect others, such as your sexual partners, your unborn children, and your health care providers, from the virus. Here’s how you can greatly reduce this risk.

HIV spreads through direct contact with certain body fluids from an HIV-positive person. But that person must have enough virus in their blood for an HIV test to detect it.

HIV only spreads through these fluids if they enter your bloodstream:

  • Blood
  • Breast milk
  • Semen
  • Pre-seminal fluid
  • Vaginal fluid

These fluids may enter the bloodstream through:

  • Smooth skin called mucous membrane on the inside of your mouth, rectum, vagina, and the tip of the penis
  • Open wounds, cuts, or sores
  • Needle injections

The most common ways that HIV gets into the bloodstream are unprotected anal or vaginal intercourse and shared needles during drug use.

Much less common ways that people get HIV are:

  • Mother to baby during pregnancy, delivery, or breastfeeding
  • Accidental needle sticks to health care providers
  • Oral sex
  • Blood transfusions, receiving blood products, or organ donation
  • Through open wounds that come in direct contact with blood from an HIV-positive person

Medications, when taken exactly as directed, can lower an HIV-positive person’s viral load to the point that it’s undetectable on a test. This makes the risk of passing it to others almost zero. Other treatments can prevent HIV in people who come into contact with the virus.

ART. Antiretroviral therapy (ART) medications can reduce the amount of HIV in your blood to undetectable levels if you take them exactly as prescribed. It may take up to 6 months for you to get the full effect. You also must go for regular viral load tests to make sure the load is undetectable and stays that way. When you reach an undetectable level, there’s virtually no risk that you will pass HIV to a partner through sex. But if you stop taking the drugs at any point, your viral load and transmission risk can go up again.

PrEP. People who are HIV-negative can take a daily medication called PrEP, or pre-exposure prophylaxis, to lower their risk of getting HIV from a partner. You should still use a condom during intercourse while you take PrEP. Only some medications protect a woman from getting HIV through vaginal intercourse. There is also an injectable medication that can be used in men and women.

PEP. If you think you have come into contact with HIV through unprotected sex, sexual assault, or shared drug needles, you can take PEP (post-exposure prophylaxis). PEP is an emergency treatment that contains ART meds. You have to take it as soon as possible, and at least within 72 hours of HIV exposure, to help prevent infection. You’ll have to take PEP for at least 28 days.

You can help prevent the spread of HIV to other people through safer-sex practices.

Condoms. When worn properly over the penis during sex, latex condoms cut the risk of passing HIV to your partner by as much as 85%. Internal or “female” condoms are sheaths inserted into a woman’s vagina. These also reduce the spread of HIV during sex.

Lubricants. Only use water- or silicone-based lubricants with latex condoms. Other lubricants may damage or break latex condoms.

Lower-risk sex.HIV risk is very low with oral sex. A dental dam makes it virtually risk-free. Sexual activities that don’t involve possible exchange of body fluids have no risk of spreading HIV. These activities are safe: masturbating, mutual genital touching, dry humping, or playing with clean sex toys.

HIV-positive mothers can transmit the virus to their baby during pregnancy, labor, or breastfeeding.

You can lower or even eliminate this risk when you:

  • Have a vaginal delivery if you’re on ART and have an undetectable viral load
  • Have a C-section, which puts the baby at a lower risk for HIV if you have a detectable viral load
  • Feed your baby with formula instead of breastmilk
  • Take ART as prescribed throughout your pregnancy (and during breastfeeding if you don’t have access to formula)

If you don’t have HIV but think you might have had contact with it during pregnancy or breastfeeding, ask your doctor about PEP right away.

Shared drug needles, syringes, needle containers, or water used to rinse shared needles can spread HIV, too. If you inject drugs, never share needles, syringes, or any other drug equipment with other people.

If you use injectable drugs, look for a needle exchange program in your community. Or go to a local pharmacy for new, sterile equipment. Also, try to seek medical help for your substance abuse and start treatment to stop using drugs. When you use drugs, you may take risks that expose you to HIV.

Tell people who may be at risk of HIV through intimate contact with you that you’re HIV positive. Once they know, they can take precautions to lower their risk. If you’re uncomfortable doing this, your local health department can tell your sex or drug-use partners about their possible HIV exposure without using your name.

People who need to know your HIV status for their safety are:

  • Sexual partners or potential sexual partners
  • People who’ve shared your needles or syringes
  • Health care providers