November 12, 2013
How Does HIV Spread During Sex?
To spread HIV during sex, HIV infection in blood or sexual fluids must be transmitted to someone. Sexual fluids come from a man's penis or from a woman's vagina, before, during, or after orgasm. HIV can be transmitted when infected fluid gets into someone's body.
You can't spread HIV if there is no HIV infection. If you and your partners are not infected with HIV, there is no risk. An "undetectable viral load" (see Fact Sheet 125) does NOT mean "no HIV infection." If there is no contact with blood or sexual fluids, there is no risk. HIV needs to get into the body for infection to occur.
Safer sex guidelines are ways to reduce the risk of spreading HIV during sexual activity.
Vaginal or rectal intercourse without protection is unsafe. Sexual fluids enter the body, and wherever a man's penis is inserted, it can cause small tears that make HIV infection more likely. The receptive partner is more likely to be infected, although HIV might be able to enter the penis, especially if it has contact with HIV-infected blood or vaginal fluids for a long time or if it has any open sores.
Some men think that they can't transmit HIV if they pull their penis out before they reach orgasm. This isn't true, because HIV can be in the fluid that comes out of the penis before orgasm.
Be aware of your body and your partner's. Cuts, sores, or bleeding gums increase the risk of spreading HIV. Rough physical activity also increases the risk.
Use a barrier to prevent contact with blood or sexual fluid. Remember that the body's natural barrier is the skin.
The most common artificial barrier is a condom for men. You can also use a female condom to protect the vagina or rectum during intercourse. Fact Sheet 153 has more information on condoms.
Lubricants can increase sexual stimulation. Oil-based lubricants like Vaseline, oils, or creams can damage condoms and other latex barriers. Be sure to use water-based lubricants.
Oral sex has low risk of transmitting HIV, but is possible if sexual fluids get in the mouth and if there are bleeding gums or sores in the mouth. Pieces of latex or plastic wrap over the vagina, or condoms over the penis, can be used as barriers during oral sex. Condoms without lubricants are best for oral sex. Most lubricants taste awful.
HIV medications can lower the risk of transmitting HIV. HIV-negative persons at risk can take medications, pre-exposure prophylaxis (PrEP, see Fact Sheet 160) before exposure, or post-exposure prophylaxis (PEP, see Fact Sheet 156) within 72 hour of exposure. A HIV+ person who takes medications and has an undetectable viral load is much less likely to infect others.
Safe activities have no risk for spreading HIV. Abstinence (never having sex) is totally safe. Sex with just one partner is safe as long as neither one of you is infected and if neither one of you ever has sex or shares needles (see Fact Sheet 154).
Fantasy, masturbation or hand jobs (where you keep your fluids to yourself), sexy talk, and non-sexual massage are also safe. There is no risk of transmitting HIV with these activities.
To be safe, assume that your sex partners are infected with HIV. You can't tell if people are infected by how they look. They could be lying if they tell you they are not infected, especially if they want to have sex with you. Some people got HIV from their steady partners who were unfaithful "just once."
Even people who got a negative test result might be infected. They might have been infected after they got tested, or they might have gotten the test too soon after they were exposed to HIV. Fact Sheet 102 has more information on HIV testing.
What if Both People Are Already Infected?
Some people who are HIV-infected don't see the need to follow safer sex guidelines when they are sexual with other infected people. However, it still makes sense to "play safe." If you don't, you could be exposed to other sexually transmitted infections such as herpes, human papillomavirus (HPV), hepatitis or syphilis. If you already have HIV, these diseases can be more serious. Choosing a sex partner based on their HIV infection status is called "sero sorting." A recent study showed that this is not a very effective way to reduce the risk of HIV infection.
Also, though uncommon, you might get "re-infected" with a different strain of HIV. This new version of HIV might be resistant to antiretroviral drugs. Following the guidelines for safer sex will reduce the risk.
Know What You're Doing
Using alcohol or drugs before or during sex greatly increases the chances that you will not follow safer sex guidelines. Be very careful if you have used any alcohol or drugs.
Set Your Limits
Decide how much risk you are willing to take. Know how much protection you want to use during different kinds of sexual activities. Before you have sex:
Stick to your limits. Don't let alcohol or drugs or an attractive partner make you forget to protect yourself.
The Bottom Line
HIV infection can occur during sexual activity. Sex is safe only if there is no HIV, no blood or sexual fluids, or no way for HIV to get into the body.
You can reduce the risk of infection if you avoid unsafe activities or if you use barriers like condoms. Decide on your limits and stick to them.