Despite significant efforts, there is no effective vaccine against HIV. The only way to prevent infection by the virus is to avoid behaviors that put you at risk, such as sharing needles or having unprotected sex. In this context, unprotected sex means sex without a barrier, such as a condom. Because condoms break, even they are not perfect protection. Many people infected with HIV don't have any symptoms. There is no way to know with certainty whether a sexual partner is infected. Here are some prevention strategies:
Abstain from sex. This obviously has limited appeal, but it absolutely protects against HIV transmission by this route.
Have sex with a single partner who is uninfected. Mutual monogamy between uninfected partners eliminates the risk of sexual transmission of HIV.
Use a condom in other situations. Condoms offer some protection if used properly and consistently. Occasionally, they may break or leak. Only condoms made of latex should be used. Only water-based lubricants should be used with latex condoms.
Do not share needles or inject illicit drugs.
If you work in a health-care field, follow national guidelines for protecting yourself against needle sticks and exposure to contaminated fluids.
If you have engaged in risky behaviors, get tested to see if you have HIV.
The risk of HIV transmission from a pregnant woman to her baby is significantly reduced if the mother takes medications during pregnancy, labor, and delivery and her baby takes medications for the first six weeks of life. Even shorter courses of treatment are effective, though not as optimal. The key is to get tested for HIV as early as possible in pregnancy. In consultation with their physician, many women opt to avoid breastfeeding to minimize the risk of transmission after the baby is born.