如何预防肛交及阴道插入感染HIV

Use condoms the right way every time you have sex, take medicines to prevent or treat HIV if appropriate, choose less risky sexual behaviors, get tested for other sexually transmitted diseases (STDs), and limit your number of sex partners. The more of these actions you take, the safer you can be.

Specifically, you can:

• Use condoms the right way every time you have sex. Learn the right way to use a male condom.
• Reduce your number of sexual partners. This can lower your chances of having a sex partner who will transmit HIV to you. The more partners you have, the more likely you are to have a partner with HIV whose viral load is not suppressed or to have a sex partner with a sexually transmitted disease. Both of these factors can increase the risk of HIV transmission.
• Talk to your doctor about pre-exposure prophylaxis (PrEP), taking HIV medicines daily to prevent HIV infection, if you are at very high risk for HIV. PrEP should be considered if you are HIV-negative and in an ongoing sexual relationship with an HIV-positive partner. PrEP also should be considered if you aren’t in a mutually monogamous relationship with a partner who recently tested HIV-negative, and you are a:
  • gay or bisexual man who has had anal sex without a condom or been diagnosed with an STD in the past 6 months;
  • man who has sex with both men and women; or
  • heterosexual man or woman who does not regularly use condoms during sex with partners of unknown HIV status who are at very high risk of HIV infection (for example, people who inject drugs or women who have bisexual male partners).
• Post-exposure prophylaxis (PEP) means taking HIV medicines after being potentially exposed to HIV to prevent becoming infected. If you’re HIV-negative or don’t know your HIV status and think you have recently been exposed to HIV during sex (for example, if the condom breaks), talk to your health care provider or an emergency room doctor about PEP right away (within 3 days). The sooner you start PEP, the better; every hour counts. If you’re prescribed PEP, you’ll need to take it once or twice daily for 28 days. Keep in mind that your chance of getting HIV is lower if your HIV-positive partner is taking medicine to treat HIV infection (called antiretroviral therapy, or ART) the right way, every day and his or her viral load remains suppressed 
• Get tested and treated for other STDs and encourage your partners to do the same. If you are sexually active, get tested at least once a year. Having other STDs increases your risk for getting or transmitting HIV. STDs can also have long-term health consequences. 
  
• If you’re HIV-negative and your partner is HIV-positive, encourage your partner to get and stay on treatment. If taken the right way, every day, the medicine to treat HIV (ART) reduces the amount of HIV (called “viral load”) in the blood and elsewhere in the body to very low levels. This is called “viral suppression.” Being virally suppressed is good for an HIV-positive person’s overall health and greatly reduces the chance of transmitting the virus to a partner.
• Choose less risky sexual behaviors. HIV is mainly spread by having anal or vaginal sex without a condom or without taking medicines to prevent or treat HIV.

Receptive anal sex is the riskiest type of sex for getting HIV. It’s possible for either partner—the partner inserting the penis in the anus (the top) or the partner receiving the penis (the bottom)—to get HIV, but it is much riskier for an HIV-negative partner to be the receptive partner. That’s because the lining of the rectum is thin and may allow HIV to enter the body during anal sex.

Vaginal sex also carries a risk for getting HIV, though it is less risky than receptive anal sex. Most women who get HIV get it from vaginal sex, but men can also get HIV from vaginal sex.

In general, there is little to no risk of getting or transmitting HIV from oral sex. Theoretically, transmission of HIV is possible if an HIV-positive man ejaculates in his partner’s mouth during oral sex. However, the risk is still very low, and much lower than with anal or vaginal sex. Factors that may increase the risk of transmitting HIV through oral sex are oral ulcers, bleeding gums, genital sores, and the presence of other STDs, which may or may not be visible. 

Sexual activities that don’t involve contact with body fluids (semen, vaginal fluid, or blood) carry no risk of HIV transmission but may pose a risk for other STDs.