How Do You Get Infected With 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.
Some people talk about "shared body fluids" being risky for HIV, but no documented cases of HIV have been caused by sweat, saliva or tears. However, even small amounts of blood in your mouth might transmit HIV during 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 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 can get infected. 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 can also be infected by drinking an infected woman's breast milk. Fact Sheet 611 has more information on pregnancy.
How Can You Protect Yourself and Others?
Unless you are 100% sure that you and the people you are with do not have HIV infection, you should take steps to prevent getting infected. People recently infected (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.
This fact sheet provides an overview of HIV prevention, and refers you to other fact sheets for more details on specific topics.
You can avoid any risk of HIV if you practice abstinence (not having sex). You also won't get infected 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 safe if:
- Both of you are uninfected (HIV-negative);
- You both have sex only with your partner; and
- 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 infection 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 women or men. For more information on condoms, see Fact Sheet 153.
Some chemicals called spermicides can prevent pregnancy but they don't prevent HIV. They might even increase your risk of getting infected if they cause irritation or swelling.
For more information on safer sex, see Fact Sheet 151.
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 get infected by tiny amounts of blood. The best way to avoid infection is to not use drugs.
If you use drugs, you can prevent infection 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. Fact Sheet 154 has more details on drug use and HIV prevention.
Some communities have started exchange programs that give free, clean syringes to people so they won't need to share.
With no treatment, up to 35% of the babies of HIV-infected women would be born infected. The risk drops to about 4% if a woman takes AZT during pregnancy and delivery, and then her newborn is given AZT. The risk is 2% 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.
Babies can get infected if they drink breast milk from an HIV-infected woman. Women with HIV should use baby formulas or breast milk from a woman who is not infected to feed their babies. 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.
What If I've Been Exposed?
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 infection, but they have some serious side effects. Fact Sheet 156 has more information on PEP.
Treatment as Prevention
In 2011 two large studies showed that the use of antiretroviral medications by people not yet infected with HIV led to significant protection against infection. This is called Pre-exposure Prophylaxis (PrEP, see Fact Sheet 160.) Discuss PrEP with your health care provider.
The Bottom Line
HIV does not spread easily from person to person. To get infected with HIV, infected blood, sexual fluid, or mother's milk has to get into your body. HIV-infected pregnant women can pass the infection to their new babies.
To decrease the risk of spreading HIV:
- Use condoms during sexual activity;
- Do not share drug injection equipment;
- If you are HIV-infected and pregnant, talk with your health care provider about taking ARVs;
- If you are an HIV-infected woman, don't breast feed any baby; and
- 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 taking ARVs.