How To Prevent HIV Infections

Today, more tools than ever are available to prevent HIV. In addition to limiting your number of sexual partners, never sharing needles, and using condoms correctly and consistently, you may be able to take advantage of newer biomedical options such as pre-exposure and post-exposure prophylaxis.

How can I prevent getting HIV from anal or vaginal sex?

Choose less risky sexual behaviors, limit your number of sex partners, use condoms, use medicines to prevent HIV if appropriate, and get checked for sexually transmitted diseases (STDs). The more of these actions you take, the safer you can be.

Specifically, you can:

  • Choose less risky sexual behaviors. Oral sex is much less risky than anal or vaginal sex. Anal sex is the highest-risk sexual activity for HIV transmission. If you are HIV-negative, insertive anal sex (topping) is less risky for getting HIV than receptive anal sex (bottoming). Sexual activities that do not involve the potential exchange of bodily fluids carry no risk for getting HIV (e.g., touching).
  • Use condoms consistently and correctly.
  • Reduce the number of people you have sex with. The number of sex partners you have affects your HIV risk. 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 medicine daily to prevent HIV infection, if you are at substantial 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 are not in an exclusive relationship with a recently tested, HIV-negative partner and 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; or
    • heterosexual man or woman who does not regularly use condoms during sex with partners of unknown HIV status who are at substantial risk of HIV infection (e.g., people who inject drugs or have bisexual male partners).
  • Talk to your doctor right away (within 3 days) about post-exposure prophylaxis (PEP) if you have a possible exposure to HIV. An example of a possible exposure is if you have anal or vaginal sex without a condom with someone who is or may be HIV-positive, and you are HIV-negative and not taking PrEP. Your chance of exposure to HIV is lower if your HIV-positive partner is taking antiretroviral therapy (ART) consistently and correctly, especially if his/her viral load is undetectable (see Can I transmit HIV if I have an undetectable viral load?). Starting PEP immediately and taking it daily for 4 weeks reduces your chance of getting HIV.
  • 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. STDs can have long-term health consequences. They can also increase your chance of getting HIV or transmitting it to others.
  • If your partner is HIV-positive, encourage your partner to get and stay on treatment. ART reduces the amount of HIV virus (viral load) in blood and body fluids. ART can keep people with HIV healthy for many years, and greatly reduce the chance of transmitting HIV to sex partners if taken consistently and correctly.

How can I prevent getting HIV from oral sex?

Avoid having your partner ejaculate in your mouth, and use barriers such as condoms, natural rubber latex sheets, dental dams, or cut-open non-lubricated condoms between your mouth and your partners’ genitals.

Oral sex involves giving or receiving oral stimulation to the penis (fellatio), the vagina (cunnilingus), or the anus (anilingus or rimming). Most types of oral sex carry little to no risk of HIV. Your highest oral sex risk is performing oral sex (fellatio) with ejaculation in your mouth. However, the risk is still low, and much lower than 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 sexually transmitted diseases (STDs) (which may or may not be visible).

The risk is lower if the partner with HIV is taking antiretroviral therapy (ART) consistently and correctly, and if the partner who is HIV-negative is taking pre-exposure prophylaxis (PrEP) consistently and correctly. Condoms and HIV medicines can greatly lower the risk of transmitting HIV.

Keep in mind that barrier methods are the only way to protect you from some STDs, including gonorrhea of the throat. And although the chance of getting or transmitting HIV from anilingus (rimming) is small, there is a big chance of transmitting hepatitis A and B, parasites, and other bacteria to the partner who is doing the rimming. There are effective vaccines that protect against hepatitis A and B and human papillomavirus infections. Talk to your health care provider to see if these are right for you, if you have not already been vaccinated.

How well do condoms prevent HIV?

When used correctly and consistently, condoms are highly effective in preventing HIV infection.

Condoms are also effective at preventing sexually transmitted diseases (STDs) transmitted through body fluids, like gonorrhea, chlamydia, and HIV. However, they provide less protection against STDs spread through skin-to-skin contact like human papillomavirus (genital warts), genital herpes, and syphilis.

There are two types of condoms: male and female.

Male Condoms

  • Latex condoms provide the best protection against HIV. Polyurethane (plastic) or polyisoprene (synthetic rubber) condoms are good options for people with latex allergies. Natural membrane (such as lambskin) condoms are porous, meaning that infections can pass through them, and therefore do not protect as well against HIV and certain other STDs.
  • Lubricants can help prevent condoms from breaking. Water-based and silicon-based lubricants are safe to use with latex condoms. Oil-based lubricants and products containing oil, such as hand lotion, Vaseline, or Crisco should not be used with latex condoms.

Female Condoms

  • Female condoms are thin pouches made of a synthetic latex product called nitrile.
  • When worn in the vagina, female condoms are just as effective as male condoms at preventing STDs, HIV and pregnancy. Some people use female condoms for anal sex. However, we do not know how well female condoms prevent HIV and other STDs when used for anal sex. But we do know that HIV cannot travel through the nitrile barrier.
  • It is safe to use any kind of lubricant with nitrile female condoms.
  • Female condoms are not recommended for use in the anus.

Although highly effective when used consistently and correctly, there is still a chance of getting HIV if you only use condoms, so adding other prevention methods can further reduce your risk (see “How can I prevent getting HIV from anal or vaginal sex?”).

Can using a lubricant help reduce my HIV risk?

Yes, because lubricants can help prevent condoms from breaking.

Water-based and silicon-based lubricants are safe to use with latex condoms. Oil-based lubricants and products containing oil, such as hand lotion, Vaseline, or Crisco should not be used with latex condoms. It is safe to use any kind of lubricant with nitrile female condoms.

Can male circumcision prevent HIV?

Male circumcision reduces the risk that a man will get HIV from an infected female partner, and for reduces risk modestly if a person is the insertive partner in anal sex “Topping”. Circumcision and also lowers the risk of other sexually transmitted infections (STIs), penile cancer, and infant urinary tract infection. Studies have not consistently shown that it prevents HIV among men who have sex with men. Circumcision is only partly effective and should be used with other prevention measures. Men who are considering circumcision should weigh its risks and costs against its potential benefits.

Can I take medicines to prevent getting HIV?

Pre-exposure prophylaxis, or PrEP, can lower the risk of getting HIV by taking a pill every day. It is for people who do not have HIV but who are at substantial risk of getting it.

CDC recommends that PrEP be considered for people who are HIV-negative and at substantial risk for HIV.

For sexual transmission, this includes anyone who is in an ongoing relationship with an HIV-positive partner. It also includes anyone who 1) is not in a mutually monogamous* relationship with a partner who recently tested HIV-negative, and 2) is

  • a gay or bisexual man who has had anal sex without a condom or been diagnosed with an STD in the past 6 months; or
  • a heterosexual man or woman who does not regularly use condoms during sex with partners of unknown HIV status who are at substantial risk of HIV infection (e.g., people who inject drugs or have bisexual male partners).

For people who inject drugs, this includes those who have injected illicit drugs in the past 6 months and who have shared equipment or been in drug treatment for injection drug use in the past 6 months.

For heterosexual couples where one partner has HIV and the other does not, PrEP is one of several options to protect the uninfected partner during conception and pregnancy.

People who use PrEP must be willing to take the drug every day and to return to their provider every 3 months for a repeat HIV test, prescription refills, and follow-up.

Some people on PrEP may have side effects like an upset stomach or loss of appetite but these are mild and usually go away in the first month.

* Mutually monogamous means that you and your partner only have sex with each other and do not have sex outside the relationship.

Can I take medicines to prevent HIV after exposure?

Yes. Post-exposure prophylaxis (PEP) is medicine that can prevent HIV after a possible exposure if started within 3 days.

An example of a possible exposure is if you have anal or vaginal sex without a condom with someone who is HIV-positive or whose HIV status you don’t know. You take PEP for 4 weeks if you may have been recently exposed to HIV and are not on PrEP. PEP keeps HIV from making copies of itself and turning into infection. To be effective, PEP must begin as soon as possible, but always within 72 hours (3 days) of a possible exposure. Keep in mind that PEP should only be used in situations right after a potential exposure. PEP is not intended for long-term use. It is not a substitute for other proven HIV prevention methods, such as correct and consistent condom use.

You should continue to use condoms with sex partners while taking PEP. If you have repeated exposures to HIV, you should consider PrEP.

Can I get vaccinated to prevent HIV?

No. There is currently no vaccine that will prevent HIV infection or treat those who have it.

Can I use microbicides to prevent HIV?

No. Microbicides are gels, films, or suppositories that can kill or neutralize viruses and bacteria. Researchers are studying both vaginal and rectal microbicides to see if they can prevent sexual transmission of HIV, but none are currently available for use.

If I am living with HIV, how can I prevent passing it to others?

If I am living with HIV, how can I prevent passing it to others? –>Specifically, you can:

  • Use ART. ART reduces the amount of virus (viral load) in your blood and body fluids. ART can keep you healthy for many years, and greatly reduce your chance of transmitting HIV to sex partners if taken consistently and correctly.
  • If you are taking ART, follow your health care provider’s advice. Visit your health care provider regularly and always take your medicine as directed.
  • Choose less risky sexual behaviors. Oral sex is much less risky than anal or vaginal sex. Anal sex is the highest-risk sexual activity for HIV transmission. During anal sex, it is less risky for your partner if you are the receptive partner (bottom) rather than the insertive partner (top). Sexual activities that do not involve the potential exchange of bodily fluids carry no risk for getting HIV (e.g., touching).
  • Use condoms consistently and correctly.
  • Talk to your partners about pre-exposure prophylaxis (PrEP), taking HIV medicine daily to prevent HIV infection. See the question “Can I take medicines to prevent getting HIV?” above.
  • Talk to your partners about post-exposure prophylaxis (PEP) if you think they have had a possible exposure to HIV. An example of a possible exposure is you have anal or vaginal sex without a condom or the condom breaks and your partner is HIV-negative and not on PrEP. Your partners’ chance of exposure to HIV is lower if you are taking ART consistently and correctly, especially if your viral load is undetectable (see “Can I transmit HIV if I have an undetectable viral load,” below). Your partners should talk to their doctors right away (within 3 days) if they think they have had a possible exposure to HIV. Starting medicine immediately (known as post-exposure prophylaxis, or PEP) and taking it daily for 4 weeks reduces your partners’ chance of getting HIV.
  • Get tested and treated for STDs and encourage your partners to do the same. If you are sexually active, get tested at least once a year. STDs can have long-term health consequences. They can also increase the chance of getting HIV or transmitting it to others.

You should also encourage your partners who are HIV-negative to get tested for HIV at least once a year so they are sure about their HIV status and can take action to keep them healthy. They may benefit from more frequent testing (e.g., every 3-6 months). (See “When should I get tested?” below). To find a testing site near them, they can call 1-800-CDC-INFO (232-4636), visit HIVtest.cdc.gov, text their ZIP code to KNOW IT (566948), or use a home testing kit.

How can I prevent getting HIV from drug use?

If you believe you cannot stop injecting drugs yet, use only sterile injection equipment and water, never share injection equipment, and use medicines to prevent HIV if appropriate. The more of these actions you take, the safer you can be.

Injecting drugs, including hormones, steroids, or silicone, can transmit HIV directly through needles or equipment (works). In addition, some drugs, such as methamphetamine, cocaine, or alcohol, may put you at risk for HIV by lowering your inhibitions and making you more likely to engage in risky behavior.

The best way to reduce your risk of HIV is to stop using drugs. If you cannot stop using drugs, talk with your doctor or health care provider, counselor, loved one, or someone else you trust about getting into a treatment program..

If you are injecting drugs and believe you cannot stop using yet, here are some other ways to reduce your risk of getting HIV or spreading it to others:

  • Ask your doctor about pre-exposure prophylaxis, or PrEP. PrEP involves taking certain HIV medicines every day to reduce the risk of getting infected with HIV.
  • Use only new needles, syringes, and other injection equipment (works, such as cookers, cotton, or water) each time you inject. Many communities have programs where you can get new needles and syringes, new injection works, and other new supplies, as well as health care services.
  • Use only new syringes that come from reliable sources (e.g., pharmacies or syringe service programs/needle-syringe programs).
  • Never share needles, syringes, or other injection works.
  • Clean used needles and syringes with bleach only when new ones are not available. Bleaching a used needle and syringe may reduce the risk of HIV but does not eliminate the risk. Needle and syringe programs often provide free bleach kits and can teach you how to use the kit.
  • Use sterile water to prepare drugs. You can buy sterile water from a store. If sterile water is not available, you can use water that has been boiled for 10 minutes or clean tap or bottled water.
  • Clean the injection site with a new alcohol swab before you inject.
  • Be careful not to touch another person’s blood.
  • Dispose of needles and syringes safely after one use. Use a sharps container or make sure to keep used needles and syringes away from other people.
  • Use condoms correctly and consistently for every act of vaginal, anal, or oral sex.
  • Get an HIV test at least once every year.

These steps, promoted in prevention programs for substance users, have helped decrease the new cases of HIV resulting from injection drug use in recent years.

One additional prevention note: If you are likely to be in a situation where alcohol and other kinds of drugs will be used, have a condom with you in case you have sex.