You can get or transmit HIV only through specific activities. Most commonly, people get or transmit HIV through sexual behaviors and needle or syringe use.
Only certain body fluids—blood, semen (cum), pre-seminal fluid (pre-cum), rectal fluids, vaginal fluids, and breast milk—from a person who has HIV can transmit HIV. These fluids must come in contact with a mucous membrane or damaged tissue or be directly injected into the bloodstream (from a needle or syringe) for transmission to occur. Mucous membranes are found inside the rectum, vagina, penis, and mouth.
In the United States, HIV is spread mainly by
- Having anal or vaginal sex with someone who has HIV without using a condom or taking medicines to prevent or treat HIV.
- For the HIV-negative partner, receptive anal sex (bottoming) is the highest-risk sexual behavior, but you can also get HIV from insertive anal sex (topping).
- Either partner can get HIV through vaginal sex, though it is less risky for getting HIV than receptive anal sex.
- Sharing needles or syringes, rinse water, or other equipment (works) used to prepare drugs for injection with someone who has HIV. HIV can live in a used needle up to 42 days depending on temperature and other factors.
Less commonly, HIV may be spread
- From mother to child during pregnancy, birth, or breastfeeding. Although the risk can be high if a mother is living with HIV and not taking medicine, recommendations to test all pregnant women for HIV and start HIV treatment immediately have lowered the number of babies who are born with HIV.
- By being stuck with an HIV-contaminated needle or other sharp object. This is a risk mainly for health care workers.
In extremely rare cases, HIV has been transmitted by
- Oral sex—putting the mouth on the penis (fellatio), vagina (cunnilingus), or anus (rimming). In general, there’s little to no risk of getting HIV from oral sex. But transmission of HIV, though extremely rare, is theoretically possible if an HIV-positive man ejaculates in his partner’s mouth during oral sex. To learn more about how to lower your risk, see Oral Sex and HIV Risk.
- Receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV. This was more common in the early years of HIV, but now the risk is extremely small because of rigorous testing of the US blood supply and donated organs and tissues.
- Eating food that has been pre-chewed by a person with HIV. The contamination occurs when infected blood from a caregiver’s mouth mixes with food while chewing. The only known cases are among infants.
- Being bitten by a person with HIV. Each of the very small number of documented cases has involved severe trauma with extensive tissue damage and the presence of blood. There is no risk of transmission if the skin is not broken.
- Contact between broken skin, wounds, or mucous membranes and HIV-infected blood or blood-contaminated body fluids.
- Deep, open-mouth kissing if both partners have sores or bleeding gums and blood from the HIV-positive partner gets into the bloodstream of the HIV-negative partner. HIV is not spread through saliva.
HIV does not survive long outside the human body (such as on surfaces), and it cannot reproduce outside a human host. It is not spread by
- Mosquitoes, ticks, or other insects.
- Saliva, tears, or sweat that is not mixed with the blood of an HIV-positive person.
- Hugging, shaking hands, sharing toilets, sharing dishes, or closed-mouth or “social” kissing with someone who is HIV-positive.
- Other sexual activities that don’t involve the exchange of body fluids (for example, touching).
Yes. In fact, anal sex is the riskiest type of sex for getting or transmitting HIV.
HIV can be found in certain body fluids—blood, semen (cum), pre-seminal fluid (pre-cum), or rectal fluids—of a person who has HIV. Although receptive anal sex (bottoming) is much riskier for getting HIV than insertive anal sex (topping), it’s possible for either partner—the top or the bottom—to get HIV. The bottom’s risk is very high because the lining of the rectum is thin and may allow HIV to enter the body during anal sex. The top is also at risk because HIV can enter the body through the opening at the tip of the penis (or urethra); the foreskin if the penis isn’t circumcised; or small cuts, scratches, or open sores anywhere on the penis. See the Prevention Q&As for information on how to lower your risk of getting HIV from anal sex.
Yes. Either partner can get HIV through vaginal sex, though it is less risky for getting HIV than receptive anal sex.
When a woman has vaginal sex with a partner who’s HIV-positive, HIV can enter her body through the mucous membranes that line the vagina and cervix. Most women who get HIV get it from vaginal sex.
Men can also get HIV from having vaginal sex with a woman who’s HIV-positive. This is because vaginal fluid and blood can carry HIV. Men get HIV through the opening at the tip of the penis (or urethra); the foreskin if they’re not circumcised; or small cuts, scratches, or open sores anywhere on the penis. See the Prevention Q&As for information on how to lower your risk of getting HIV from vaginal sex.
The chance that an HIV-negative person will get HIV from oral sex with an HIV-positive partner is extremely low.
Oral sex involves putting the mouth on the penis (fellatio), vagina (cunnilingus), or anus (anilingus). In general, there’s little to no risk of getting or transmitting HIV through oral sex.
Factors that may increase the risk of transmitting HIV through oral sex are ejaculation in the mouth with oral ulcers, bleeding gums, genital sores, and the presence of other sexually transmitted diseases (STDs), which may or may not be visible.
You can get other STDs from oral sex. And, if you get feces in your mouth during anilingus, you can get hepatitis A and B, parasites like Giardia, and bacteria like Shigella, Salmonella, Campylobacter, and E. coli.
For information on how to lower your risk of getting HIV or other STDs from oral sex, see Oral Sex and HIV Risk.
Yes. Having another sexually transmitted disease (STD) can increase the risk of getting or transmitting HIV.
If you have another STD, you’re more likely to get or transmit HIV to others. Some of the most common STDs include gonorrhea, chlamydia, syphilis, trichomoniasis, human papillomavirus (HPV), genital herpes, and hepatitis. The only way to know for sure if you have an STD is to get tested. If you’re sexually active, you and your partners should get tested for STDs (including HIV if you’re HIV-negative) regularly, even if you don’t have symptoms.
If you are HIV-negative but have an STD, you are about 3 times as likely to get HIV if you have unprotected sex with someone who has HIV. There are two ways that having an STD can increase the likelihood of getting HIV. If the STD causes irritation of the skin (for example, from syphilis, herpes, or human papillomavirus), breaks or sores may make it easier for HIV to enter the body during sexual contact. Even STDs that cause no breaks or open sores (for example, chlamydia, gonorrhea, trichomoniasis) can increase your risk by causing inflammation that increases the number of cells that can serve as targets for HIV.
If you are HIV-positive and also have another STD, you are about 3 times as likely as other people with HIV to transmit HIV through sexual contact. This appears to happen because there is an increased concentration of HIV in the semen and genital fluids of HIV-positive people who also have another STD.
For more information about the connection between HIV and other STDs, see STDs and HIV. To get tested for HIV or other STDs, find a testing site near you.
Yes. As an HIV-positive person’s viral load goes down, the chance of transmitting HIV can go down dramatically.
Viral load is the amount of HIV in the blood of someone who has HIV. Taking HIV medicine (called antiretroviral therapy or ART) as prescribed can make the viral load very low—so low that a test can’t detect it (called an undetectable viral load). People with HIV who take HIV medicine as prescribed and get and keep an undetectable viral load have effectively no risk of transmitting HIV to an HIV-negative partner through sex.
If you’re HIV-positive, getting into care and taking HIV medicine as prescribed will give you the greatest chance to get and keep an undetectable viral load; live a longer, healthier life; and protect your partners.
If you’re HIV-negative and have an HIV-positive partner, encourage your partner to get into care and to take HIV medicine as prescribed.
Treatment is a powerful tool for preventing sexual transmission of HIV. But it works only as long as the HIV-positive partner gets and keeps an undetectable viral load. Here are some things to consider when deciding whether treatment as prevention is right for you and your partner:
- Not everyone taking HIV medicine has an undetectable viral load. Up to one-third of people in HIV care don’t keep an undetectable viral load. To stay undetectable, people with HIV must take HIV medicine every day as prescribed.
- Missing some doses can increase the viral load and the risk of transmitting HIV. People who have trouble taking medicine as prescribed can talk with their health care provider about the challenges they are facing and develop a plan to ensure they take their medicine every day. They should also consider using other prevention strategies like condoms.
- We don’t know how often people living with HIV need to have their viral load tested if they are using their undetectable viral load status as their only prevention method. But to stay healthy and protect their partners, they need to visit their provider regularly and get a viral load test as recommended.
- Some people who take HIV medicine daily can get an undetectable viral load very quickly, but it can take some people up to six months. The only way to know if you are undetectable is by getting your viral load tested.
- People taking HIV medicine sometimes have small increases or “blips” in their viral load. These blips usually go back down by the next viral load test. But people who experience blips may benefit from using other prevention strategies (condoms) until their viral load is undetectable again.
- HIV medicine does not protect against other STDs.
- Both partners should learn about all their options for preventing HIV, as well as other STDs, so they can make the decisions that are best for them.
Consider other actions to prevent HIV, like using condoms or a negative partner being on pre-exposure prophylaxis (PrEP), especially if the person with HIV
- Has trouble regularly taking HIV medicine,
- Has an increased viral load, or a load of 200 copies/ml of blood or greater,
- Hasn’t had a recent test (last 6 months) that shows the viral load is undetectable,
- Missed some doses since the last viral load test, or
- Has stopped taking HIV medicine in the past and may choose to do so again.
Important Note: Consider using condoms if either partner is concerned about getting or transmitting other STDs.
Yes. Your risk for getting HIV is very high if you use needles or works (such as cookers, cotton, or water) after someone with HIV has used them.
People who inject drugs, hormones, steroids, or silicone can get HIV by sharing needles or syringes and other injection equipment. The needles and equipment may have someone else’s blood in them, and blood can transmit HIV. Likewise, you’re at risk for getting hepatitis B and C if you share needles and works because these infections are also transmitted through blood.
Another reason people who inject drugs can get HIV (and other sexually transmitted diseases) is that when people are high, they’re more likely to have risky sex.
Stopping injection and other drug use can lower your chances of getting HIV a lot. You may need help to stop or cut down using drugs, but many resources are available.
Although HIV transmission is possible in health care settings, it is extremely rare.
Careful practice of infection control, including universal precautions (using protective practices and personal protective equipment to prevent HIV and other blood-borne infections), protects patients as well as health care providers from possible HIV transmission in medical and dental offices and hospitals.
The risk of getting HIV from receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV is extremely small because of rigorous testing of the US blood supply and donated organs and tissues.
It is important to know that you cannot get HIV from donating blood. Blood collection procedures are highly regulated and safe.
It is possible to get HIV from a reused or not properly sterilized tattoo or piercing needle or other equipment, or from contaminated ink.
It’s possible to get HIV from tattooing or body piercing if the equipment used for these procedures has someone else’s blood in it or if the ink is shared. The risk of getting HIV this way is very low, but the risk increases when the person doing the procedure is unlicensed, because of the potential for unsanitary practices such as sharing needles or ink. If you get a tattoo or a body piercing, be sure that the person doing the procedure is properly licensed and that they use only new or sterilized needles, ink, and other supplies.
You can’t get HIV from consuming food handled by someone with HIV. Even if the food contained small amounts of HIV-infected blood or semen, exposure to the air, heat from cooking, and stomach acid would destroy the virus.
Though it is very rare, HIV can be spread by eating food that has been pre-chewed by someone with HIV. The contamination occurs when infected blood from a caregiver’s mouth mixes with food while chewing. The only known cases are among infants.
