Prevention

You can keep from getting HIV by avoiding behaviors that might result in contact with infected blood, semen, or vaginal fluids.

• Practice safe sex to prevent HIV. Always use a condom during sexual activity, unless you are in a relationship with one partner who does not have HIV or other sex partners.
• If you do have sex with someone who has HIV, it is important to practice safe sex and to be regularly tested for HIV.
• Reduce your number of sex partners, preferably to one partner.
• Talk with your sex partner or partners about their sexual history as well as your own sexual history. Find out whether your partner has engaged in high-risk behaviors.
• Avoid alcohol and drugs, which can impair both your judgment and your immune system. People who know and understand safer sex practices may not practice them when they are under the influence of alcohol or drugs.
• Do not share intravenous (IV) needles, syringes, cookers, cotton, cocaine spoons, or eyedroppers with others if you use drugs.

You may also be able to take a combination medicine (tenofovir plus emtricitabine) every day to help prevent infection with HIV. This medicine can lower the risk of getting HIV.^{11, 12} But the medicine is expensive, and you still need to practice safe sex to keep your risk low.

If you are infected with HIV, you can greatly lower the risk of spreading the infection to your sex partner by starting antiretroviral therapy (ART) when your immune system is still healthy. A large study sponsored by the U.S. National Institutes of Health (NIH) found that the risk of spreading HIV to an uninfected partner was reduced by 96% when the HIV-positive partner started treatment before his or her CD4 count dropped below 350.¹³ This study was done mainly with heterosexual couples, so the effectiveness of HIV treatment in preventing the spread of HIV to a same-sex partner may be different.

If you are HIV-positive (infected with HIV) or have engaged in sex or needle-sharing with someone who could be infected with HIV, take precautions to avoid spreading the infection to others.

• Tell your sex partner or partners about your behavior and whether you are HIV-positive.
• Follow safe sex practices, such as using condoms.
• Do not donate blood, plasma, semen, body organs, or body tissues.
• Do not share personal items, such as toothbrushes, razors, or sex toys, that may be contaminated with blood, semen, or vaginal fluids.

The risk of a woman spreading HIV to her baby can be greatly reduced if she is on medicine that reduces her viral load (HIV RNA) to undetectable levels during pregnancy, if she receives AZT (ZDV) before the baby is born, and if she does not breast-feed her baby. The baby should also receive treatment after it is born.

If you do not regularly engage in high-risk behaviors for HIV, such as having unprotected sex or injecting drugs, and you feel you have been exposed this way, contact your doctor as soon as possible. He or she may recommend medicine if your exposure was within the past 72 hours.⁷