The odds of getting HIV from sex are generally low. However, the risk can vary by the specific sexual act or type of exposure.

The World Health Organization (WHO) states that at the end of 2022, approximately 39 million people were living with HIV worldwide. According to, around 1.2 million people in the United States have HIV.

Some people living with HIV may not know they have it.

This article discusses how certain behaviors affect the risk of HIV transmission.

It also covers methods of preventing HIV transmission, what to do if someone has concerns about HIV exposure, and guidance for finding support.

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HIV is a virus that destroys immune cells.

As a result, HIV weakens the body’s immune system, leaving the body vulnerable to infections.

An HIV infection can eventually lead to stage 3 HIV, formerly known as AIDS, if a person does not receive treatment.

HIV affects people of all ages, races, ethnicities, genders, sexual orientations, and socioeconomic backgrounds.

Of the 39 million people worldwide living with HIV in 2022:

  • 37.5 million were adults
  • 1.5 million were children under age 15 years
  • 5.5 million did not know they were living with HIV
  • 1.3 million contracted HIV in 2022

HIV can be transmitted through different bodily fluids, including:

  • blood
  • semen and pre-seminal fluid
  • vaginal secretions
  • rectal fluids
  • breast milk

HIV transmission only occurs if the bodily fluids of a person with detectable levels of HIV enter the bloodstream of a person who does not have HIV.

HIV can enter the bloodstream through:

  • cuts or broken skin
  • open sores
  • direct injection
  • mucous membranes, such as those found in the mouth, rectum, vagina, and tip of the penis

HIV can also pass from the birthing parent to the child during pregnancy. This is called vertical transmission.

HIV is not transmitted through:

  • insects
  • air or water
  • saliva, tears, or sweat
  • toilet seats
  • day-to-day contact, such as shaking hands, hugging, or kissing

Learn more about HIV and AIDS here.

The chances of getting HIV from a single exposure can depend on the type of exposure.

However, merely describing a person’s risk of contracting HIV as “high” or “low” is vague. These terms lack the necessary quantifiable information to accurately assess the risk of specific behaviors.

The next section describes exposure risk in more detail.

The Centers for Disease Control and Prevention (CDC) provides the following risk estimates for HIV transmission based on different types of exposure to HIV:

Type of exposureRisk per 10,000 exposuresRisk per single exposure (percentage)
receptive anal intercourse1381.38%
insertive anal intercourse110.11%
receptive penile-vaginal intercourse80.08%
insertive penile-vaginal intercourse40.04%
receptive oral intercourselowlow
insertive oral intercourselowlow
needle-sharing during injection drug use630.63%

Anal sex

The CDC notes that anal intercourse, regardless of a person’s gender or sexual orientation, has the highest risk of HIV transmission among sexual activities.

The chance of contracting HIV via one encounter of anal sex is as follows:

  • receptive anal intercourse: 1.38%
  • insertive anal intercourse: 0.11%

Although both partners can contract HIV via anal sex, the receptive partner has a higher chance. This is because the lining of the rectum is thin and easily injured.

The insertive partner may contract HIV via the urethra or small cuts, scratches, and open sores on the penis.

Having a rectal infection, such as herpes, may also increase the risk of transmission.

Vaginal sex

Either sexual partner can contract HIV via vaginal sex.

HIV can be contracted through the lining of the vagina and cervix if the sexual partner’s bodily fluids, such as semen and pre-seminal fluid, carry HIV.

Limited research is available on the rates of HIV transmission via insertive penile sex in a neovagina.

HIV can also be contracted from the vaginal fluid and blood through the opening of the penis, the foreskin, and small cuts and scratches or open sores.

The chance of contracting HIV via one encounter of vaginal sex is as follows:

  • receptive penile-vaginal intercourse: 0.08%
  • insertive penile-vaginal intercourse: 0.04%

Having a vaginal infection may also increase the risk of transmission.

Oral sex

The CDC notes there is little to no risk of contracting HIV via oral sex.

Mouth-to-penis oral sex may carry the highest chance of transmitting HIV, but the chances are still very low.

Factors that may increase the chance of contracting HIV via oral sex include:

Other sexual activities

Although it is possible to transmit HIV through the following activities, the chance is low to nonexistent:

  • Fingering: To lessen the chance of transmission, a person should ensure they have clean hands and trimmed fingernails to not damage the walls of the anus or vagina.
  • Sex toy use: HIV transmission is rare through sharing sex toys, such as dildos, vibrators, and anal plugs. However, other STIs may be more readily transmissible this way. A person should clean their sex toys between each use and avoid sharing them.

Transmitted during pregnancy

Research has found that the transmission rate during pregnancy, labor, delivery, and breastfeeding or chestfeeding is 15–45% without any medical intervention, according to the WHO.

However, the risk is lower if the pregnant person takes antiretroviral (ART) drugs during pregnancy and while breastfeeding or chestfeeding.

Transmission through needles

HIV transmission through needles occurs when a person who does not have HIV uses the same needle or syringe as someone who has HIV.

Used syringes usually contain residual fluid, such as blood, on the needle or nozzle.

When people who use injectable drugs share needles and syringes, they risk exposing themselves to blood containing infectious microbes.

According to the CDC, the chance of transmission via shared needle use is 0.63% during a single instance.

People who seek help for substance use can contact the Substance Abuse and Mental Health Services Administration (SAMHSA) at 800-662-4357 or visit

STIs are transmitted from person to person through sexual activities, such as anal, vaginal, or oral sex.

Examples of STIs include:

STIs can also lead to open sores on the skin and the mucous membranes of the vagina, penis, anus, and rectum. HIV can enter the bloodstream through an open sore or a break in the skin.

Certain behaviors can increase a person’s risk of STIs and HIV. These behaviors include:

  • having sex without a condom or other barrier method
  • having sex with multiple partners
  • having sex while intoxicated
  • having sex while having an STI
  • using injectable drugs

People living with HIV can take the following medications to prevent transmitting it to others:

  • Preexposure prophylaxis (PrEP): This daily pill contains two antivirals: tenofovir and emtricitabine. When a person takes it daily, PrEP can reduce the risk of contracting HIV through sex by 99%. PrEP is for people who do not have HIV but have a high risk of contracting it.
  • Postexposure prophylaxis (PEP): These ART drugs can prevent HIV infection after potential exposure. The CDC recommends starting PEP within 72 hours of a recent potential HIV exposure.

People can also get tested for HIV. The Denver Prevention Training Center developed a scoring system to determine whether a person has an increased risk of having an undiagnosed HIV infection. The center recommends people at high risk get regular testing.

HIV treatment as prevention

People with HIV can take ART drugs to lower their chance of transmitting HIV to others.

ART drugs reduce the quantity of HIV in the body, or viral load, and keep it at a low or undetectable level.

The term “viral load” refers to the number of HIV copies per milliliter of blood.

Healthcare professionals define successful viral suppression as having a viral load under 200 copies of HIV per milliliter of blood. Achieving and maintaining viral suppression significantly reduces the risk of HIV transmission.

Other ways to prevent HIV transmission include:

  • using a condom or other barrier method during sex
  • reducing the number of sexual partners
  • getting vaccinated against other STIs, such as HPV and hepatitis B
  • avoiding using injectable drugs, if possible
  • if using injectable drugs, not sharing needles and syringes
  • following all workplace safety protocols

People can speak with a doctor to learn more about their individual risk of contracting HIV.

A person can find support whether they are concerned about exposure or are living with HIV.

What to do if a person is concerned about HIV exposure

Anyone concerned about HIV exposure can contact a healthcare professional or a local emergency room to get testedand receive PEP.

The CDC notes that healthcare professionals who suspect they may have experienced exposure to HIV in their workplace can call the PEPline at 888-448-4911.

Support groups

HIV discrimination is the unjust treatment of a person based on their real or perceived HIV status.

Other people who may encounter HIV discrimination include family members, friends, and partners of a person living with HIV.

The following support services are available to people living with HIV:

People can search for HIV and AIDS resources in their area using A Positive Life, an online resource.

When to consult a healthcare professional

A person can consult a healthcare professional if they are concerned about HIV exposure.

People who take medication for HIV can plan on attending follow-up appointments with their doctor every 6 months if their HIV is well controlled and stable.

Can you sleep with a person with HIV and not get infected?

If a person living with HIV takes daily treatment for HIV and has an undetectable viral load, sex cannot transmit HIV. Other preventive measures include using a condom or other barrier method, PrEP, or PEP.

How are you most likely to get HIV?

People who receive daily ART treatment and have an undetectable viral load cannot transmit HIV. But people may have HIV without knowing it.

Transmission methods with the greatest risk include:

  • receptive anal sex
  • needle-sharing during drug use
  • vertical transmission during pregnancy and breastfeeding or chestfeeding

Does everyone who is exposed to HIV get infected?

Not everyone exposed to HIV contracts HIV. A person may be able to prevent HIV infection after potential exposure by taking PEP.

Certain behaviors can increase a person’s chance of contracting HIV. HIV transmits through bodily fluids, such as blood, semen, and breast milk. Some people may not know they have HIV.

People can use preventive measures, such as PREP, PEP, and ART drugs, to lower their chance of contracting and transmitting HIV through sex. They can also use condoms or other barrier methods.

Read this article in Spanish.