WHAT IS PRE-EXPOSURE PROPHYLAXIS?
Prophylaxis means disease prevention. Pre-exposure prophylaxis (PrEP) is medicine people at risk for HIV take to prevent getting HIV from sex or injection drug use. Large research studies have shown that PrEP helps prevent new HIV infections when used by people at high risk of getting HIV.
ARE THERE DIFFERENT TYPES OF PREP?
There are two antiretroviral medications (ARVs) approved for use as PrEP: Truvada and Descovy
- Truvada (emtricitabine + tenofovir DF) is for all people at risk through sex or injection drug use.
- Descovy (emtricitabine + tenofovir AF) is for people at risk through sex, except for people assigned female at birth (AFAB) who are at risk of getting HIV from vaginal sex.
WHO SHOULD USE PREP?
PrEP may be right for you if you test negative for HIV, and any of the following apply to you:
You have had anal or vaginal sex in the past 6 months and you:
- have a sexual partner with HIV (especially if the partner has an unknown or detectable viral load) OR
- have not consistently used a condom OR
- have been diagnosed with a sexually transmitted infection (STI) in the past 6 months
You inject drugs and you:
- have an injection partner with HIV OR
- share needles, syringes, or other equipment to inject drugs (for example, cookers)
You have been prescribed PEP (post-exposure prophylaxis) and you:
- report continued risk behavior OR
- have used multiple courses of PEP
If you are AFAB and are considering pregnancy, talk to your healthcare provider about PrEP if you’re not already taking it. PrEP may be an option to help protect you and your baby from getting HIV while you try to get pregnant, during pregnancy, or while breastfeeding.
PrEP is approved for use by adolescents without HIV who weigh at least 75 pounds (35 kg) and who are at risk for getting HIV from sex or injection drug use.
HOW IS PREP TAKEN?
PrEP is currently one tablet of Truvada or Descovy daily. It can be taken with food or between meals. There is research ongoing to look at other medications for PrEP. Truvada and Descovy are only available with a prescription.
HOW WELL DOES PREP WORK?
PrEP is highly effective for preventing HIV. PrEP reduces the risk of getting HIV from sex by about 99% when taken as prescribed. Although there is less information about how effective PrEP is among people who inject drugs (PWID), we do know that PrEP reduces the risk of getting HIV by at least 74% when taken as prescribed. PrEP is much less effective when it is not taken as prescribed.
HOW LONG DO I HAVE TO TAKE PREP BEFORE IT IS HIGHLY EFFECTIVE?
PrEP reaches maximum protection from HIV for receptive anal sex (bottoming) at about 7 days of daily use. For receptive vaginal sex and injection drug use, PrEP reaches maximum protection at about 21 days of daily use.
No data are available for insertive anal sex (topping) or insertive vaginal sex.
WHAT ARE THE SIDE EFFECTS?
Some people experience side effects like diarrhea, nausea, headache, fatigue, and stomach pain. These side effects usually go away over time.
HOW CAN I START PREP?
Talk to your healthcare provider if you think PrEP may be right for you. PrEP can be prescribed only by a healthcare provider.
Before beginning PrEP, you must take an HIV test to make sure you don’t have HIV.
While taking PrEP, you’ll have to visit your healthcare provider every 3 months for follow-up visits, HIV tests, and prescription refills.
Ask your healthcare provider about self-testing and telehealth services for follow-up visits. With telemedicine (phone or video consultation with a healthcare provider) and mail-in self-testing, it is possible to order a specimen collection kit which contains the supplies to do all the testing required to start or continue taking PrEP, even if an in-person appointment is not possible. Contact your healthcare provider to see what options are available to you.
You can locate a PrEP provider online.
WHAT IF I NEED TO STOP TAKING PREP?
There are several reasons why people stop taking PrEP:
- Your risk of getting HIV becomes low because of changes in your life.
- You don’t want to take a pill as prescribed or often forget to take your pills.
- You have side effects from the medicine that are interfering with your life.
- Blood tests show that your body is reacting to PrEP in unsafe ways.
Talk to your healthcare provider about other HIV prevention methods that may work better for you.
IF I STOPPED TAKING PREP, HOW DO I START TAKING IT AGAIN?
Tell your healthcare provider that you would like to start taking PrEP again. You will need to take an HIV test before you restart PrEP to make sure you don’t have HIV.
CAN I TAKE PREP JUST ONCE, IF I THINK I MIGHT HAVE BEEN EXPOSED TO HIV?
PrEP is for people who are at ongoing risk for HIV. PrEP is not the right choice for people who may have been exposed to HIV in the last 72 hours. If you may have been exposed to HIV in the last 72 hours, talk to your healthcare provider, an emergency room clinician, or an urgent care provider about post-exposure prophylaxis (PEP).
IF I AM NOT AT ONGOING RISK FOR GETTING HIV, CAN I TAKE PREP ONLY WHEN I’M AT RISK?
Taking PrEP only when you are at risk for getting HIV is known as on-demand PrEP. It is also known as intermittent, non-daily, event-driven, or off-label PrEP use.
The type of on-demand PrEP that has been studied is the 2-1-1 schedule. This means taking 2 pills 2-24 hours before sex, 1 pill 24 hours after the first dose, and 1 pill 24 hours after the second dose. There is scientific evidence that the 2-1-1 schedule provides effective protection for cisgender men who have sex with men (MSM) when having anal sex without a condom. We don’t know how on-demand PrEP works for heterosexual people, PWID, and transgender people.
Some health departments in the U.S. and some health organizations in Europe and Canada are offering guidance for on-demand PrEP as an alternative to daily PrEP for MSM at risk for HIV.
This type of use is not currently part of CDC’s guidelines for PrEP use, which still recommends daily use for those at risk for HIV. Taking PrEP once a day is currently the only FDA-approved schedule for PrEP to prevent HIV. When taken as prescribed, PrEP is highly effective for preventing HIV.
CAN I STOP USING CONDOMS IF I TAKE PREP?
PrEP provides protection from HIV but does not protect against other STIs. Condoms can help prevent other STIs that can be transmitted through genital fluids, such as gonorrhea and chlamydia. Condoms are less effective at preventing STIs that can be transmitted through sores or cuts on the skin, like human papillomavirus (HPV), genital herpes (herpes simplex virus or HSV), and syphilis.
HOW CAN I PAY FOR PREP?
Ready, Set, PrEP makes PrEP medications available at no cost to those who qualify.
Most insurance plans and state Medicaid programs cover PrEP. There are also other programs that provide PrEP for free or at a reduced cost:
Co-pay assistance programs, such as Gilead’s Advancing Access Program, help lower the costs of PrEP medications. Income is not a factor in eligibility.
A number of states have established their own PrEP Assistance Programs. Most cover out-of-pocket expenses for the medication as well as clinical visits and labs.
- California PrEP Assistance Program or call (877) 495-0990
- Colorado AIDS Drug Assistance/Public Health Intervention Program
- Washington DC PrEP Drug Assistance Program or call (202) 671-4815
- Florida: call (850) 245-4422 for more information about Florida’s PrEP Drug Assistance program
- Illinois PrEP Assistance Program
- Massachusetts PrEP Drug Assistance Program or call (617) 502-1737
- New York Uninsured Care Programs or call (800) 542-2437
- Ohio PAPI program or call (800) 332-2437
- Virginia: Call (800) 533-4148 for more information about Virginia’s PrEP Drug Assistance Program
- Washington PrEP Drug Assistance Program or call (877) 376-9316
THE BOTTOM LINE
Pre-exposure prophylaxis (PrEP) is the use of antiretroviral medications before exposure to HIV to reduce the risk of HIV infection. When PrEP is used correctly and consistently, it can reduce the rate of HIV infection by sexual activity by as much as 99%.
The benefits of PrEP are potentially very high for reducing new HIV infections in people who recognize their risk of infection and can take PrEP to protect themselves. Some people fear PrEP may encourage unsafe behaviors, but this has not been seen.
CDC: PrEP 101 Info Sheet
HIV.gov: Pre-Exposure Prophylaxis
HIVinfo.NIH.gov: Pre-Exposure Prophylaxis
Reviewed March 2021Print PDF