two people holding up a PrEP pill like an umbrella in a downpour

Fast Facts about PrEP

Last updated: March 2022

PrEP stands for pre-exposure prophylaxis. PrEP is a way to reduce the risk of getting HIV (human immunodeficiency virus). PrEP is currently available as a prescription pill or an injection for people who test HIV-negative. The pills must be taken daily. The injection is given every 2 months after an initial ramp-up period.1

When taken consistently, PrEP reduces the risk of HIV infection through sex by about 99 percent. This means it provides almost complete protection from HIV. Some studies have found even higher effectiveness among gay and bisexual men and transgender women who use PrEP consistently.1,2

In people who are injection drug users, PrEP is about 74 percent effective if taken as prescribed.1

What are the PrEP drugs?

The drugs used for PrEP are also used to treat HIV infection. When used for PrEP, the dosage is different. The brand names are:1

  • Truvada®, a daily pill for both men and women
  • Descovy® a daily pill for men only
  • Apretude, an injection every 2 months

Generic versions of PrEP drugs are available in the United States.

How does PrEP prevent HIV?

PrEP is not a vaccine. It is a drug that builds up in the bloodstream so that your body can fight off HIV. If PrEP is not taken as prescribed, the amount of drug in the bloodstream decreases. This makes it harder for your body to block the virus and makes you more likely to become infected.1,2

Who should take PrEP?

PrEP is recommended for anyone who wants protection from HIV. This includes:1,2

  • People who are sexually active with a person who is HIV-positive
  • People who have unprotected sex often, especially if you do not know the HIV status of the other person
  • People who are injection drug users or have sex with injection drug users

You must be HIV-negative to take PrEP. This is because PrEP by itself is not a complete treatment for HIV. That means if you already have HIV, over time PrEP will make the virus harder to treat.3

When does it start to work?

PrEP must be taken every day for 7 to 20 days before it offers protection, depending on which drug you are taking.2

When taken as directed, PrEP protects people from getting HIV. It does not protect against pregnancy or sexually transmitted infections (STIs). Condoms should still be used to prevent pregnancy, gonorrhea, chlamydia, and syphilis.2

How do I get PrEP?

PrEP must be prescribed by a healthcare provider – such as a doctor or nurse practitioner – in most places. California passed a law allowing pharmacists to provide PrEP directly to customers. If you need to find a provider or your doctor is reluctant to prescribe PrEP, check out the HIV.gov locator.1

Once you begin taking PrEP, you will need to see your doctor every 3 months for: 1

  • Repeat HIV tests
  • Prescription refills
  • Other medical care

How much does PrEP cost?

Not all health clinics or doctor’s offices offer PrEP and the drug can be expensive. Most insurance plans, Medicaid, and Medicare cover at least part of the costs of PrEP. The companies that make PrEP drugs also offer programs to help people pay for their products.

If you do not have insurance or need help paying for out-of-pocket costs, there are several programs that will help you pay for PrEP, including:1,5

  • Greater Than AIDS
  • National Prevention Information Network
  • Ready, Set, PrEP
  • State programs
  • Health centers that will adjust their fees to your ability to pay
  • Patient Advocate Foundation
  • Good Days
  • PAN Foundation

Are there side effects?

PrEP generally has few side effects and those go away over time. Current studies have found no long-term health effects in people who took PrEP for up to 5 years. Common short-term side effects include:1,3,4,6

  • Nausea
  • Headache
  • Stomach pain

If regular doctor visits are not practical for you, you may be able to find a doctor who will do telehealth appointments and send orders for your regular blood tests to a lab near you. You also may need to find other ways to prevent HIV infection.

Other HIV risk-reduction methods

If taking a daily pill does not work for you, there are other ways to reduce your risk of HIV infection. Note that these methods are not as effective as PrEP. They include:

  • Using condoms with water-based lubricants
  • Abstinence
  • Getting circumcised

If you have recently been exposed to HIV, PEP or post-exposure prophylaxis or post-exposure prophylaxis may be an option for you. PEP must be started within 72 hours of possible exposure to HIV.2

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