HIV Prevention

Preventing Perinatal Transmission of HIV

  • Key Points

    • People should get tested for HIV before they become pregnant or as early as possible during each pregnancy and during the third trimester. The earlier HIV is detected, the sooner HIV medicines (also known as antiretrovirals) can be started.
    • Perinatal transmission of HIV is when HIV is passed from a person with HIV to their child during pregnancy, childbirth (also called labor and delivery), or breastfeeding (through breast milk). Perinatal transmission of HIV is also called mother-to-child transmission of HIV.
    • Pregnant people with HIV should take antiretroviral therapy (ART) throughout pregnancy and childbirth to prevent perinatal transmission of HIV. ART is the use of a combination of HIV medicines (antiretrovirals) to treat HIV. The use of HIV medicines and other strategies have helped lower the rate of perinatal transmission of HIV to 1% or less in the United States and Europe.
    • Most pregnant people with HIV can have vaginal deliveries.  If someone has a high viral load (more than 1,000 copies/mL) or an unknown viral load near the time of delivery, a scheduled cesarean delivery (sometimes called a C-section) can reduce the risk of perinatal transmission of HIV.
    • After birth, babies born to people with HIV should receive HIV medicines to reduce the risk of perinatal transmission. Several factors determine what HIV medicines babies receive and how long they receive the medicines.
    • Although HIV can be transmitted through breastfeeding, taking HIV medicines and having an undetectable viral load during pregnancy and throughout breastfeeding lower the risk of passing HIV to less than 1%. Pregnant people with HIV should talk to their health care provider about options for feeding their baby.

  • Is HIV testing recommended for pregnant people?

    The Centers for Disease Control and Prevention (CDC) recommends that all people get tested for HIV before they become pregnant and as early as possible during each pregnancy and in the third trimester. The earlier HIV is detected, the sooner HIV medicines can be started.

    All people who are pregnant or trying to get pregnant should encourage their partners also to get tested for HIV and, if possible, screened for other sexually transmitted infections (STIs). STIs can increase the amount of HIV in the body (viral load) in people with HIV. If any partner has HIV, that partner should take HIV medicine as prescribed to stay healthy and prevent transmission.

  • What is perinatal transmission of HIV?

    Perinatal transmission of HIV is when HIV is passed from a person with HIV to their child during pregnancy, childbirth (also called labor and delivery), or breastfeeding (through breast milk). Perinatal transmission of HIV is also called mother-to-child transmission of HIV and vertical transmission of HIV.

    The use of HIV medicines and other strategies have helped to lower the rate of perinatal transmission of HIV to 1% or less in the United States and Europe. (HIV medicines are called antiretrovirals.)

  • How do HIV medicines prevent perinatal transmission of HIV?

    Antiretroviral therapy (ART) is the use of HIV medicines to treat HIV infection. Pregnant people with HIV should take HIV medicines to reduce the risk of perinatal transmission of HIV. The earlier HIV medicines are started, the more effective they are at preventing perinatal transmission of HIV. People with HIV who are trying to conceive should start HIV medicines before they become pregnant to prevent perinatal transmission. Pregnant and breastfeeding people with HIV should take HIV medicines throughout pregnancy, childbirth, and breastfeeding to prevent perinatal transmission. HIV medicines also protect the birthing parent’s health.

    HIV medicines, when taken as prescribed, prevent HIV from multiplying and reduce viral load. An undetectable viral load is when the level of HIV in the blood is too low to be detected by a viral load test. The risk of perinatal transmission of HIV during pregnancy and childbirth is lowest when a person with HIV has an undetectable viral load. Having an undetectable viral load during pregnancy and throughout breastfeeding lowers the risk of perinatal transmission of HIV to less than 1%. Maintaining an undetectable viral load also helps keep the parent-to-be healthy.

    After birth, babies born to people with HIV receive medicines to reduce the risk of transmission of HIV. Several factors determine what medicines babies receive and how long they receive the medicines.

  • Are HIV medicines safe to use during pregnancy?

    HIV medicines are safe to use during pregnancy. HIV medicines do not increase the risk of birth defects. Health care providers discuss the benefits and risks of specific HIV medicines when helping people with HIV decide which medicines to use during pregnancy or while they are trying to conceive. If an individual gets pregnant while on HIV medication, they should stay on that medication unless instructed to change by their health care provider.

  • Are there other ways to prevent perinatal transmission of HIV?

    In people who have a high HIV viral load (more than 1,000 copies/mL) or an unknown viral load near the time of delivery, a cesarean delivery (sometimes called a C-section) can reduce the risk of perinatal transmission.

    Pregnant people with HIV are encouraged to talk to their medical team about options for feeding their baby after birth. With consistent use of HIV medicine and an undetectable viral load during pregnancy and throughout breastfeeding, the risk of transmission to a breastfed baby is low: less than 1%, but not zero. Alternatively, properly prepared formula and pasteurized donor human milk from a milk bank are options that eliminate the risk of transmission to a baby after birth. Pregnant people with HIV can speak with their health care provider to determine what method of feeding their baby is right for them.

    Additionally, babies should not eat food that was pre-chewed by a person with HIV.

  • This fact sheet is based on information from the following sources:

    From CDC:

    From the Department of Health and Human Services:

    Also see the HIV Source collection of HIV links and resources. For more information regarding infant feeding for people with HIV, see HIVE and the Well Project.

The Basics of HIV Prevention

  • Key Points

    • Protect yourself during sex: To reduce your risk of getting HIV, use condoms correctly every time you have sex.
    • Protect yourself if you inject drugs: Do not inject drugs. If you do, use only sterile injection equipment and water, and never share your equipment with others.
    • Protect yourself taking PrEP: If you do not have HIV but are at risk of getting HIV, talk to your health care provider about pre-exposure prophylaxis (PrEP). PrEP involves taking a specific HIV medicine every day or an injectable HIV medicine every two months to reduce the risk of getting HIV through sex or injection drug use.
    • Protect others if you have HIV: Take HIV medicine (called antiretroviral therapy or ART) as prescribed by your doctor. ART can reduce the amount of HIV in the blood (called viral load) to the point where a test cannot detect it (called an undetectable viral load). If you have an undetectable viral load, you will not transmit HIV to your partner through sex.
    • Prevent perinatal transmission: If you have HIV and take HIV medicine as prescribed by your doctor throughout pregnancy and childbirth, the chances of transmitting HIV to your baby are less than 1%. If you have a partner with HIV and are considering getting pregnant, talk to your doctor about PrEP to help protect you and your baby from getting HIV while you try to get pregnant, during pregnancy, or while breastfeeding.

  • How is HIV transmitted?

    The person-to-person spread of human immunodeficiency virus (HIV) is called HIV transmission. People can get or transmit HIV only through specific activities, such as sex or injection drug use. HIV can be transmitted only in certain body fluids from a person who has HIV. Bodily fluids that can transmit HIV include blood, semen (“cum”), pre-seminal fluids (“pre-cum”), rectal fluids, vaginal fluids, and breast milk.

    HIV transmission is only possible if these fluids come in contact with a mucous membrane, open cuts or sores, or are directly injected into the bloodstream (from a contaminated needle or syringe). Mucous membranes are found inside the rectum, the vagina, the opening of the penis, and the mouth.

    In the United States, HIV is transmitted mainly by:

    • Having anal or vaginal sex with someone who has HIV without using a condom or who is not taking medicines to prevent or treat HIV.
    • Sharing injection drug equipment (“works”), such as needles or syringes, with someone who has HIV.

    HIV can also be transmitted from a birthing parent with HIV to their child during pregnancy, childbirth (also called labor and delivery), or breastfeeding. This is called perinatal transmission of HIV. Perinatal transmission of HIV is also called mother-to-child transmission of HIV.

  • How is HIV not transmitted?

    You cannot get HIV from:

    • Casual contact with a person who has HIV, such as a handshake, a hug, or a closed-mouth kiss (“social” kissing).
    • Contact with objects, such as toilet seats, doorknobs, or dishes used by a person who has HIV.
    • Mosquitoes, ticks, or other biting insects.
    • Other sexual activities that do not involve the exchange of body fluids (for example, touching).
    • Donating blood or receiving a blood transfusion.

    Use the You Can Safely Share…With Someone With HIV infographic from HIVinfo to spread this message.

  • How can I reduce the risk of getting HIV?

    Anyone can get HIV, but you can take steps to protect yourself from HIV.

    • Get tested for HIV. Talk to your partner about HIV testing and get tested before you have sex. Use the GetTested locator from the Centers for Disease Control and Prevention (CDC) to find an HIV testing location near you.
    • Choose less risky sexual behaviors. HIV is mainly transmitted by having anal or vaginal sex without a condom or without taking medicines to prevent or treat HIV.
    • Use condoms every time you have sex. Read this fact sheet from CDC on how to use condoms correctly.
    • Limit your number of sexual partners. The more partners you have, the more likely you are to have a partner with poorly controlled HIV or to have a partner with a sexually transmitted infection (STI). Both factors can increase the risk of HIV transmission.
    • Get tested and treated for STDs. Insist that your partners get tested and treated, too. Having an STD can increase your risk of getting HIV or transmitting it to others.
    • Talk to your health care provider about pre-exposure prophylaxis (PrEP). PrEP is an HIV prevention option for people who do not have HIV but who are at risk of getting HIV (for example, if your partner has HIV or if you inject drugs). PrEP involves taking a specific HIV medicine to reduce the risk of getting HIV through sex or injection drug use. PrEP medications can be given in the form of pills (taken daily) or injections (every other month). It is important to take PrEP as directed by your doctor to effectively protect you against HIV. For more information, read the HIVinfo fact sheet on Pre-Exposure Prophylaxis (PrEP).
    • Do not inject drugs. But if you do, use only sterile drug injection equipment and water, and never share your equipment with others.

  • How can I prevent passing HIV to others if I have HIV?

    Take HIV medicines as directed by your doctor. Treatment with HIV medicines (called antiretroviral therapy or ART) helps people with HIV live long, healthy lives. ART cannot cure HIV, but it can reduce the amount of HIV in the body (called the viral load). One of the main goals of ART is to reduce a person's viral load to an undetectable level.

    An undetectable viral load means that the level of HIV in the blood is too low to be detected by a viral load test. People with HIV who maintain an undetectable viral load by taking ART consistently as prescribed have effectively no risk of transmitting HIV to an HIV-negative partner through sex.

    Remember, taking HIV medicines does not prevent transmission of other STIs.

    In addition to maintaining an undetectable viral load, here are some other steps you can take to make sure you prevent HIV transmission to others:

    • Use condoms correctly every time you have sex.
    • Talk to your partner about taking PrEP.
    • If you inject drugs, do not share your needles, syringes, or other drug equipment with other people.

  • Are HIV medicines used at other times to prevent HIV transmission?

    Yes, HIV medicines are also used for post-exposure prophylaxis (PEP) and to prevent perinatal transmission of HIV.

    • Post-exposure prophylaxis (PEP) 
      PEP means taking HIV medicines within 72 hours after a possible exposure to HIV to prevent HIV infection. PEP should be used only in emergency situations. It is not meant for regular use by people who may be exposed to HIV frequently. For more information, read the HIVinfo fact sheet on Post-Exposure Prophylaxis (PEP).   
    • Prevention of perinatal transmission of HIV 
      Pregnant people with HIV take HIV medicines for their own health and to prevent perinatal transmission of HIV (HIV can be passed from a person with HIV to their child during pregnancy, childbirth, or breastfeeding). After birth, babies born to people with HIV receive HIV medicine to protect them from infection with any HIV that may have passed from mother to child during childbirth. For more information, read the HIVinfo fact sheet on Preventing Perinatal Transmission of HIV.

  • This fact sheet is based on information from the following sources:

    From CDC:

    From the NIH Office of AIDS Research:

    Also see the HIV Source collection of HIV links and resources.

Preventing Perinatal Transmission of HIV

  • Key Points

    • People should get tested for HIV before they become pregnant or as early as possible during each pregnancy and during the third trimester. The earlier HIV is detected, the sooner HIV medicines (also known as antiretrovirals) can be started.
    • Perinatal transmission of HIV is when HIV is passed from a person with HIV to their child during pregnancy, childbirth (also called labor and delivery), or breastfeeding (through breast milk). Perinatal transmission of HIV is also called mother-to-child transmission of HIV.
    • Pregnant people with HIV should take antiretroviral therapy (ART) throughout pregnancy and childbirth to prevent perinatal transmission of HIV. ART is the use of a combination of HIV medicines (antiretrovirals) to treat HIV. The use of HIV medicines and other strategies have helped lower the rate of perinatal transmission of HIV to 1% or less in the United States and Europe.
    • Most pregnant people with HIV can have vaginal deliveries.  If someone has a high viral load (more than 1,000 copies/mL) or an unknown viral load near the time of delivery, a scheduled cesarean delivery (sometimes called a C-section) can reduce the risk of perinatal transmission of HIV.
    • After birth, babies born to people with HIV should receive HIV medicines to reduce the risk of perinatal transmission. Several factors determine what HIV medicines babies receive and how long they receive the medicines.
    • Although HIV can be transmitted through breastfeeding, taking HIV medicines and having an undetectable viral load during pregnancy and throughout breastfeeding lower the risk of passing HIV to less than 1%. Pregnant people with HIV should talk to their health care provider about options for feeding their baby.

  • Is HIV testing recommended for pregnant people?

    The Centers for Disease Control and Prevention (CDC) recommends that all people get tested for HIV before they become pregnant and as early as possible during each pregnancy and in the third trimester. The earlier HIV is detected, the sooner HIV medicines can be started.

    All people who are pregnant or trying to get pregnant should encourage their partners also to get tested for HIV and, if possible, screened for other sexually transmitted infections (STIs). STIs can increase the amount of HIV in the body (viral load) in people with HIV. If any partner has HIV, that partner should take HIV medicine as prescribed to stay healthy and prevent transmission.

  • What is perinatal transmission of HIV?

    Perinatal transmission of HIV is when HIV is passed from a person with HIV to their child during pregnancy, childbirth (also called labor and delivery), or breastfeeding (through breast milk). Perinatal transmission of HIV is also called mother-to-child transmission of HIV and vertical transmission of HIV.

    The use of HIV medicines and other strategies have helped to lower the rate of perinatal transmission of HIV to 1% or less in the United States and Europe. (HIV medicines are called antiretrovirals.)

  • How do HIV medicines prevent perinatal transmission of HIV?

    Antiretroviral therapy (ART) is the use of HIV medicines to treat HIV infection. Pregnant people with HIV should take HIV medicines to reduce the risk of perinatal transmission of HIV. The earlier HIV medicines are started, the more effective they are at preventing perinatal transmission of HIV. People with HIV who are trying to conceive should start HIV medicines before they become pregnant to prevent perinatal transmission. Pregnant and breastfeeding people with HIV should take HIV medicines throughout pregnancy, childbirth, and breastfeeding to prevent perinatal transmission. HIV medicines also protect the birthing parent’s health.

    HIV medicines, when taken as prescribed, prevent HIV from multiplying and reduce viral load. An undetectable viral load is when the level of HIV in the blood is too low to be detected by a viral load test. The risk of perinatal transmission of HIV during pregnancy and childbirth is lowest when a person with HIV has an undetectable viral load. Having an undetectable viral load during pregnancy and throughout breastfeeding lowers the risk of perinatal transmission of HIV to less than 1%. Maintaining an undetectable viral load also helps keep the parent-to-be healthy.

    After birth, babies born to people with HIV receive medicines to reduce the risk of transmission of HIV. Several factors determine what medicines babies receive and how long they receive the medicines.

  • Are HIV medicines safe to use during pregnancy?

    HIV medicines are safe to use during pregnancy. HIV medicines do not increase the risk of birth defects. Health care providers discuss the benefits and risks of specific HIV medicines when helping people with HIV decide which medicines to use during pregnancy or while they are trying to conceive. If an individual gets pregnant while on HIV medication, they should stay on that medication unless instructed to change by their health care provider.

  • Are there other ways to prevent perinatal transmission of HIV?

    In people who have a high HIV viral load (more than 1,000 copies/mL) or an unknown viral load near the time of delivery, a cesarean delivery (sometimes called a C-section) can reduce the risk of perinatal transmission.

    Pregnant people with HIV are encouraged to talk to their medical team about options for feeding their baby after birth. With consistent use of HIV medicine and an undetectable viral load during pregnancy and throughout breastfeeding, the risk of transmission to a breastfed baby is low: less than 1%, but not zero. Alternatively, properly prepared formula and pasteurized donor human milk from a milk bank are options that eliminate the risk of transmission to a baby after birth. Pregnant people with HIV can speak with their health care provider to determine what method of feeding their baby is right for them.

    Additionally, babies should not eat food that was pre-chewed by a person with HIV.

  • This fact sheet is based on information from the following sources:

    From CDC:

    From the Department of Health and Human Services:

    Also see the HIV Source collection of HIV links and resources. For more information regarding infant feeding for people with HIV, see HIVE and the Well Project.

Pre-Exposure Prophylaxis (PrEP)

  • Key Points

    • Pre-exposure prophylaxis (PrEP) is HIV medicine taken to reduce the chances of getting HIV infection. PrEP is used by people who do not have HIV but are at high risk of being exposed to HIV through sex or injection drug use.
    • When taken as prescribed by your doctor, PrEP can help you stay protected against HIV if a condom breaks, is not used correctly, or is not used every time.
    • Two HIV oral medicines (pills) are approved by the U.S. Food and Drug Administration (FDA) for use as PrEP: Truvada and Descovy. To be effective, you must take oral PrEP medicines consistently each day.
    • The FDA has approved a new, long-acting injectable PrEP medicine: Apretude. It is delivered as an injection once every two months. Likewise, you must take PrEP injections at the prescribed time to be effective.
    • It is important to know that PrEP does not protect you against other sexually transmitted diseases (STDs) and should always be used with condoms.
    • The Centers for Disease Control and Prevention (CDC) reports that studies on PrEP effectiveness have shown that consistent use of PrEP reduces the risk of getting HIV from sex by about 99% and from injection drug use by at least 74%.

  • What is PrEP?

    PrEP stands for pre-exposure prophylaxis. The word “prophylaxis” means to prevent or control the spread of an infection or disease.

    Three HIV medicines are approved by the U.S. Food and Drug Administration (FDA) for use as PrEP: Truvada, Descovy, and Apretude. Which medicine to use for PrEP depends on a person’s individual situation.

    If a person is exposed to HIV through sex or injection drug use, having the PrEP medicine in the bloodstream can stop HIV from taking hold and spreading throughout the body. However, if PrEP is not taken as prescribed, there may not be enough medicine in the bloodstream to block the virus.

  • Should I consider taking PrEP?

    PrEP is used by people who are HIV negative and at high risk of being exposed to HIV through sex or injection drug use. If you have HIV, PrEP medicine is not for you.

    Specifically, the Centers for Disease Control and Prevention (CDC) recommends that you should consider PrEP if you are HIV negative, have had anal or vaginal sex in the past 6 months, and:

    PrEP is also recommended if you inject drugs and you:

    • have an injection partner with HIV, or
    • share needles, syringes, or other equipment to inject drugs.

    PrEP should also be considered for people without HIV who have been prescribed non-occupational post-exposure prophylaxis (nPEP) and:

    • report continued risk behavior, or
    • have used multiple courses of PEP.

    If you think PrEP may be right for you, talk to your health care provider.

  • How well does PrEP work?

    Oral PrEP is most effective when taken consistently each day. CDC reports that studies on PrEP effectiveness have shown that consistent use of PrEP reduces the risk of getting HIV from sex by about 99% and from injection drug use by at least 74%.

    Currently, Apretude shots are not recommended for people who inject drugs. Descovy is not for use in people assigned female at birth who are at risk of getting HIV from vaginal sex, because its effectiveness has not been studied.

    Adding other prevention methods, such as condom use, along with PrEP can further reduce your risk of getting HIV.

  • Does PrEP cause side effects?

    In some people, PrEP can cause side effects, such as nausea, diarrhea, headache, dizziness, depression, insomnia, etc. These side effects are not serious and generally go away over time. 

    If you are taking PrEP, tell your health care provider if you have any side effects that bother you or that do not go away.

  • What should you do if you think that PrEP can help you?

    If you think PrEP may be right for you, see a health care provider. PrEP can be prescribed only by a health care provider. If your health care provider agrees that PrEP may reduce your risk of getting HIV, the next step is an HIV test. You must have a negative HIV test immediately before starting PrEP.

  • What happens once you start PrEP?

    Once you start oral PrEP (Truvada or Descovy), you will need to take your PrEP pills every day. PrEP is much less effective when it is not taken every day.

    Likewise, if you are taking Apretude, do not miss any injections. Missing injections increases your risk of getting infected with HIV.

    Continue to use condoms while taking PrEP. Even though daily PrEP can greatly reduce your risk of HIV, it does not protect against other STIs, such as gonorrhea and chlamydia. Combining condom use with PrEP will further reduce your risk of HIV, as well as protect you from other STIs.  

    You must also take an HIV test every 3 months while taking PrEP, so you will have regular follow-up visits with your health care provider. If you are having trouble taking PrEP every day or if you want to stop taking PrEP, talk to your health care provider.

    If you do become HIV positive, you will need to take other medicines to treat HIV. PrEP medications and protocols are not approved for treatment of people with HIV.

Post-Exposure Prophylaxis (PEP)

  • Key Points

    • Post-exposure prophylaxis (PEP) means taking HIV medicines within 72 hours (3 days) after a possible exposure to HIV to prevent HIV.
    • PEP should be used only in emergency situations. It is not meant for regular use by people who may be exposed to HIV frequently. PEP is not a substitute for regular use of other HIV prevention methods such as pre-exposure prophylaxis (PrEP)
    • PEP must be started within 72 hours after a possible exposure to HIV. The sooner PEP is started after a possible HIV exposure, the better. Every hour counts.
    • If you are prescribed PEP, you will take HIV medicines every day for 28 days.
    • PEP is effective in preventing HIV when it is taken correctly.

  • What is PEP?

    PEP stands for post-exposure prophylaxis. The word “prophylaxis” means to prevent or control the spread of an infection or disease. PEP means taking HIV medicines within 72 hours (3 days) after a possible exposure to HIV to prevent HIV.

    PEP should be used only in emergency situations. It is not meant for regular use by people who may be exposed to HIV frequently. PEP is not intended to replace regular use of other HIV prevention methods, such as consistent and proper use of condoms during sex or pre-exposure prophylaxis (PrEP). PrEP is different than PEP, in that people at risk for HIV take a specific HIV medicine daily or an injection every two months to prevent getting HIV.

    For more information, see the HIVinfo fact sheets on The Basics of HIV Prevention and Pre-Exposure Prophylaxis (PrEP).

  • Who should consider taking PEP?

    PEP may be prescribed for people who are HIV negative or do not know their HIV status, and who in the last 72 hours:

    • May have been exposed to HIV during sex
    • Shared needles or other equipment (works) to inject drugs
    • Were sexually assaulted
    • May have been exposed to HIV at work (occupational exposure)

    If you think you were recently exposed to HIV, talk to your health care provider or an emergency room doctor about PEP right away.

    A health care worker who has a possible exposure to HIV should seek medical attention immediately.

  • When should PEP be started?

    PEP must be started within 72 hours (3 days) after a possible exposure to HIV. The sooner PEP is started after a possible HIV exposure, the better. Every hour counts. According to research, PEP will most likely not prevent HIV infection if it is started more than 72 hours after a person is exposed to HIV.

    If you are prescribed PEP, you will need to take the HIV medicines every day for 28 days.

  • What HIV medicines are used for PEP?

    The Centers for Disease Control and Prevention (CDC) provides guidelines on recommended HIV medicines for PEP. The CDC guidelines include recommendations for specific groups of people, including adults and adolescents, children, pregnant people, and people with kidney problems. The most recent PEP recommendations can be found on CDC’s PEP resources webpage.

    Your health care provider or emergency room doctor will work with you to determine which medicines to take for PEP.

  • How well does PEP work?

    PEP is effective in preventing HIV when it is taken correctly, but it is not 100% effective. The sooner PEP is started after a possible HIV exposure, the better. Every hour counts. The exact effectiveness of PEP is difficult to measure, but observational research suggests that PEP can reduce the risk of getting HIV by more than 80%. The effectiveness is highly dependent on adherence (taking PEP every day for 28 days) and in the case of non-occupational exposure, no further exposures to HIV. Effectiveness is likely much higher than 80% if PEP is used consistently and correctly, as prescribed.

    While taking PEP, it is important to keep using other HIV prevention methods, such as consistently and properly using condoms with sex partners and using only new, sterile needles and syringes when injecting drugs.

  • Does PEP cause side effects?

    The HIV medicines used for PEP may cause side effects in some people. The side effects can be treated and are not life-threatening. If you are taking PEP, talk to your health care provider if you have any side effect that bothers you or that does not go away.