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International Association of Providers of AIDS Care
Reviewed January 9, 2017

Fact Sheet 150

Stopping the Spread of HIV





The Human Immunodeficiency Virus (HIV) is not spread easily. You can only get HIV if you get infected blood or sexual fluids into your system. You can’t get it from mosquito bites, coughing or sneezing, sharing household items, or swimming in the same pool as someone with HIV. You also can't get HIV from a sex partner who is living with HIV, is taking HIV treatment, and has very low viral load (below 200 copies, one large 2016 study showed).

No documented cases of HIV have been caused by sweat, saliva or tears. In extremely rare cases, even small amounts of blood in your mouth might transmit HIV during open-mouth kissing or oral sex. Blood can come from flossing your teeth, or from sores caused by gum disease, or by eating very hot or sharp, pointed food.

To infect someone, the virus has to be a detectable level in the body of the person living with HIV. It then has to get past the body’s defenses. These include skin and saliva. If your skin is not broken or cut, it protects you against infection from blood or sexual fluids. Saliva can help kill HIV in your mouth. If HIV-infected blood or sexual fluid gets inside your body, you may become HIV positive. This can happen through an open sore or wound, during sexual activity, or if you share equipment to inject drugs.

HIV can also be spread from a mother to her child during pregnancy or delivery. This is called “vertical transmission.” A baby may also become HIV-positive by drinking breast milk from a woman living with HIV. Fact Sheet 611 has more information on pregnancy.


Unless you are 100% sure that you and the people you have sex or share needs with are not living with HIV, you should take steps to prevent becoming HIV positive. People who recently acquired HIV (within the past 2 or 3 months) are most likely to transmit HIV to others. This is when their viral load is the highest. In general, the risk of transmission is higher with higher viral loads, as it is lower with lower viral loads.

This fact sheet provides an overview of HIV prevention, and refers you to other fact sheets for more details on specific topics.

Sexual Activity:

You can avoid any risk of HIV if you practice abstinence (not having sex). You also won’t get acquire HIV if your penis, mouth, vagina, or rectum doesn’t touch anyone else’s penis, mouth, vagina, or rectum. Safe activities include kissing, erotic massage, masturbation, or hand jobs (mutual masturbation). There are no documented cases of HIV transmission through wet clothing.

Having sex in a monogamous (faithful) relationship is protective against HIV only if:

  • Both of you are HIV-negative, or the HIV-positive partner is taking HIV treatment and has very low viral load
  • You both have sex only with your partner
  • Neither one of you gets exposed to HIV through drug use or other activities

Oral sex has a lower risk of infection than anal or vaginal sex especially if there are no open sores or blood in the mouth. See Fact Sheet 152 for information on the risks of various behaviors.

You can reduce the risk of acquiring with HIV and other sexually transmitted diseases by using barriers like condoms. Traditional condoms go on the penis. The "female" condom goes in the vagina or in the rectum of receptive men and women. For more information on condoms, see Fact Sheet 153.

Some condoms contain chemicals called spermicides which prevent pregnancy, but not HIV. They might even increase your risk of HIV if they cause irritation or swelling.

When people living with HIV are on treatment and their viral loads are very low or undetectable, the chance they will transmit HIV is virtually zero. HIV treatment does not prevent other sexually transmitted diseases.

For more information on safer sex, see Fact Sheet 151.

 Drug Use:

If you’re high on drugs, you might forget to use protection during sex. If you use someone else’s equipment (needles, syringes, cookers, cotton or rinse water) you can acquire HIV through tiny amounts of blood.

The best way to avoid HIV acquisition is to not use drugs. If you use drugs, you can prevent acquisition by not injecting them. If you do inject, don’t share equipment. If you must share, clean equipment with bleach and water before every use. Some communities have started exchange programs that give free, clean syringes to people so they won't need to share. Fact Sheet 154 has more details on drug use and HIV prevention.

Vertical Transmission:

With no treatment, up to 35% of the babies of HIV-positive women would be born with HIV. The risk drops to about 1% or less if the mother is taking combination antiretroviral therapy (ART). Caesarean section deliveries probably don't reduce transmission risk if the mother's viral load is below 1000.

Breast milk is one of the bodily fluids that contains HIV. However, if the mother and/or the baby take ART during breastfeeding, this significantly reduces the risk that the baby will acquire HIV. Guidelines on whether to breastfeed vary depending on what resources are available in your area. Fact Sheet 611 has more information on HIV and pregnancy.

Contact with Blood:

HIV is one of many diseases that can be transmitted by blood. Be careful if you are helping someone who is bleeding. If your work exposes you to blood, be sure to protect any cuts or open sores on your skin, as well as your eyes and mouth. Your employer should provide gloves, facemasks and other protective equipment, plus training about how to avoid diseases that are spread by blood.


If you think you have been exposed to HIV, talk to your health care provider or the public health department, and get tested. For more information on HIV testing, see Fact Sheet 102.

If you are sure that you have been exposed, call your health care provider immediately to discuss whether you should start taking antiretroviral drugs (ARVs.) This is called “post exposure prophylaxis” or PEP. You would take two or three medications for several weeks. These drugs can decrease the risk of HIV acquisiton, but may have side effects. Fact Sheet 156 has more information on PEP.



In addition to PEP, taking "pre-exposure prophylaxis" or PrEP offers significant protection against HIV for people who are vulnerable to becoming HIV-positive. PrEP is only available by prescription, and only works if taken regularly. Discuss PrEP with your health care provider.  Fact sheet 160 also has information on PrEP.


HIV does not spread easily from person to person. Blood, sexual fluid, or breast containing detectable levels of HIV must get into your body in order to transmit HIV.

To decrease the risk of spreading HIV:

  • Use condoms during sexual activity
  • Do not share drug injection equipment
  • If you are HIV-positive, taking ART will reduce the risk of HIV transmission to virtually zero.
  • If you are HIV-positive and pregnant, taking ART can reduce the risk of vertical transmission to 1% or less. Talk with your provider about this, and about whether or not you should breast feed.
  • Protect cuts, open sores, and your eyes and mouth from contact with blood.

If you think you’ve been exposed to HIV, get tested and ask your health care provider about treatment as prevention.


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