The most common way people are infected with HIV is by having sex with an infected person. You can't tell by looking at a person whether they have HIV, so you have to protect yourself -- and your sex partner.
Don't have unprotected sex outside marriage or a committed relationship. If you or your partner has ever had unprotected sex -- or if either of you uses injected drugs -- the only way to be sure you don't have HIV is to get tested. Have two HIV tests six months apart, with no new sex partners or injection drug use between tests.
You can't get HIV if your penis, mouth, vagina, or anus doesn't touch another person's penis, mouth, vagina, or anus. Kissing, erotic massage, and mutual masturbation are safe sex activities.
You can greatly reduce your risk by using a latex or polyurethane condom during sex. Don't use natural-skin condoms -- they prevent pregnancy, but they don't prevent infections. Put on the condom on as soon as you or a male partner has an erection, not just before ejaculation. Use a lubricant -- but never use an oil-based lubricant with a latex condom. The female condom, called a vaginal pouch, also protects against disease.
Oral sex without a condom or latex dam is not safe, but it's far safer than unprotected intercourse.
The HIV drug Truvada has been approved for use in those at high risk as a way to prevent HIV infection. It's to be used in conjunction with safe sex practices.
Drug Use and HIV Prevention
Using drugs increases your HIV risk. If you're not ready to stop taking drugs, you can still reduce your risk of getting HIV/AIDS. Here's how:
Don't have sex when you're high. It's easy to forget about safe sex when you're on drugs.
If you must use drugs, don't inject them.
If you must inject drugs, don't share the equipment. This includes every piece of it: needles, syringes, cookers, cotton, and rinse water. Some states have needle-exchange programs where you can trade in dirty equipment for new equipment.
Pregnancy and HIV Prevention
Mothers with HIV can give the virus to their infants during pregnancy, delivery, or breastfeeding. If you're pregnant, get an HIV test. Anti-HIV drugs taken during pregnancy and delivery can greatly reduce the risk of passing the virus to your baby. If you have HIV, feed your infant formula or breast milk from an uninfected woman.
Blood Contact and HIV Prevention
Although transmission is rare, you can be infected by HIV from contact with the blood of an infected person. If you're helping a bleeding person, be careful to avoid getting his or her blood into any cuts or open sores on your own skin -- or in your eyes or mouth. If possible, wear gloves and protective eyewear.
Call Your Doctor About HIV/AIDS If:
You think you may have been exposed to HIV, see your doctor or visit an emergency center immediately. Your doctor may recommend taking anti-HIV drugs to try to prevent the virus from infecting you. These drugs are most effective if started right away. This is not like taking a "morning-after pill;" treatment involves several weeks of taking drugs with potentially serious side effects -- but it can keep you from getting HIV infection.
SOURCES: World Health Organization: "HIV Infection." Centers for Disease Control: "HIV/AIDS" and "Deciding If and When To Be Tested." UNAIDS. Betts, R.; Chapman, W.; Penn R. A Practical Approach To Infectious Diseases,Lippincott Williams & Wilkins, 5th edition, 2005. Heymann, D. Control of Communicable Diseases Manual, 18th edition. American Public Health Association: Washington, DC, 2004. Lashley, F.; Durham, J., Emerging Infectious Diseases: Trends and Issues, Springer Publishing, 2004. FDA web site.