Key takeaways
- HIV transmission only occurs if the bodily fluids of someone with detectable levels of HIV pass into the bloodstream of someone without HIV.
- The odds of getting HIV from sex are generally low. However, the risk can vary by the specific sexual act or type of exposure. Anal sex may pose the highest risk.
- People can take steps to lower the risk of and prevent HIV transmission, including antiretroviral (ART) treatment, preexposure prophylaxis (PrEP), and postexposure prophylaxis (PEP).
HIV is a virus that destroys immune cells, leaving the body vulnerable to infections. An HIV infection can eventually lead to stage 3 HIV, formerly known as AIDS, if someone does not receive treatment.
HIV affects people of all ages, races, ethnicities, genders, sexual orientations, and socioeconomic backgrounds. Some people living with HIV may not know they have it.
This article explains how certain behaviors affect the risk of HIV transmission, methods of preventing HIV transmission, what to do if someone has concerns about HIV exposure, and guidance for finding support.
The World Health Organization (WHO) states that at the end of 2024, approximately
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 someone 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.
Transmission misconceptions
HIV does not transmit through the following methods:
- insects
- air or water
- saliva, tears, or sweat
- toilet seats
- day-to-day contact, such as shaking hands, hugging, or kissing
The chances of getting HIV from a single exposure can depend on the type of exposure.
Describing a person’s risk of contracting HIV as “high” or “low” is vague. These terms lack the necessary information to accurately assess the risk of specific behaviors.
The next section describes exposure risk in more detail.
The
| Type of exposure | Risk per 10,000 exposures | Risk per single exposure (percentage) |
|---|---|---|
| receptive anal intercourse | 138 | 1.38% |
| insertive anal intercourse | 11 | 0.11% |
| receptive penile-vaginal intercourse | 8 | 0.08% |
| insertive penile-vaginal intercourse | 4 | 0.04% |
| receptive oral intercourse | low | low |
| insertive oral intercourse | low | low |
| needle-sharing during injection drug use | 63 | 0.63% |
Anal sex
HIV.gov notes that anal intercourse, regardless of a person’s gender or sexual orientation, has the highest risk of HIV transmission among sexual activities without barrier contraception.
The
- 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. Someone can contract HIV 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. However, a neovagina may be a more inflammatory environment, which may contribute to an increased risk of HIV transmission.
People can also contract HIV from vaginal fluid and blood through the opening of the penis, the foreskin, and small cuts and scratches or open sores.
According to the
- 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
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:
- sores on the vagina, mouth, or penis
- bleeding gums
- oral contact with menstrual blood
- the presence of other sexually transmitted infections (STIs)
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 avoid damaging 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 STIsmay be more readily transmissible this way. To limit transmission, clean sex toys between each use and avoid sharing them.
Transmission during pregnancy
According to the WHO, research suggests HIV transmission rates during pregnancy, labor, delivery, and nursing are
However, the risk is lower if the pregnant person takes antiretroviral (ART) drugs during pregnancy and while nursing.
Transmission through needles
HIV transmission through needles occurs when someone without HIV uses the same needle or syringe as someone who has HIV.
Used syringes may contain residual fluid, such as blood, on the needle or nozzle. When people who inject 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
Help is available
Seeking help for addiction may feel daunting or even scary, but several organizations can provide support.
If you believe that you or someone close to you is showing signs of addiction, you can contact the following organizations for immediate help and advice:
- Substance Abuse and Mental Health Services Administration (SAMHSA): 800-662-4357 (TTY: 800-487-4889)
- 988 Suicide & Crisis Lifeline: 988
STIs can be transmitted through sexual activities, such as anal, vaginal, or oral sex. Examples of STIs include:
STIs
Certain behaviors can increase a person’s risk of STIs and HIV, including:
- sex without a condom or other barrier method
- sex with multiple partners
- sex while using drugs or alcohol
- injecting drugs
The following medications may help reduce and prevent HIV transmission:
- Preexposure prophylaxis (PrEP): This daily pill contains two antivirals — tenofovir and emtricitabine. 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. People must start PEP within 72 hours of a recent potential HIV exposure, though starting as soon as possible is best.
People can also test for HIV. The Denver Prevention Training Center developed a scoring system to determine whether someone has an increased risk of 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.
Healthcare professionals define successful viral suppression as having a viral load
The following methods can also reduce the risk of HIV transmission:
- use a condom or other barrier method during sex
- reduce the number of sexual partners
- get vaccinated against other STIs, such as HPV and hepatitis B
- avoid injecting drugs, if possible
- if injecting drugs, avoid sharing needles and syringes
People can speak with a doctor to learn more about their individual risk of contracting HIV.
Key terms explained: Viral load
The viral load refers to the number of HIV copies per milliliter of blood.
A healthcare professional can offer support for anyone concerned about HIV exposure or living with the virus.
People who take medication for HIV can attend follow-up appointments with their doctor every 6 months if their HIV is stable.
Anyone concerned about HIV exposure can contact a healthcare professional or a local emergency room for testing and PEP.
The
HIV support and advocacy groups
HIV discrimination is the unjust treatment based on a person’s real or perceived HIV status. Family members, friends, and partners of someone living with HIV may also encounter HIV discrimination.
The following support services are available to people living with HIV:
- The Joint United Nations Programme on HIV/AIDS is an international organization aiming to end stage 3 HIV by 2030.
- The Ryan White HIV/AIDS Program provides primary medical care and support services to people living with HIV.
- The International AIDS Society (IAS) is the world’s largest association of HIV professionals. IAS and its members promote evidence-based and human rights-based efforts to reduce HIV’s global impact.
People can also speak with their healthcare team for more information on local HIV resources.
If someone 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.
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 nursing
Not everyone who has HIV exposure contracts the virus. People 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.
Preventive measures, such as PREP, PEP, and ART drugs, can lower the chance of contracting and transmitting HIV through sex. People can also use condoms or other barrier methods.