PrEP is short for pre-exposure prophylaxis. It is an FDA-approved prescription medication that protects against getting HIV. Similar to birth control, but for HIV.

It is available as both a pill and long-acting injectable (or shot). Both forms of PrEP are highly effective at preventing HIV when taken as prescribed. As a pill, PrEP is taken once a day. Another option is to get it as an injection every two months from a healthcare provider. A healthcare provider can discuss the benefits of both options. It takes some time, usually a few weeks after starting PrEP, for it to reach maximum protection. You must continue using PrEP to maintain a high-level of protection.

As part of ongoing PrEP, you will need to see a healthcare provider every few months to be re-tested for HIV and other health checks.

PrEP may also be taken “on demand,” referred to as PrEP 211, in advance of sex. For more about using PrEP in this form, see: CDC guidance for On-Demand PrEP.

Most people pay little or nothing for PrEP. Federal law requires that almost all health insurers cover daily oral PrEP. Insurers cannot charge people on daily PrEP any out-of-pocket fees such as copays for the medication or the required clinic visits. If you do not have health insurance, or need help paying for PrEP, financial assistance is often available. A PrEP navigator can help you with options.

There is currently no requirement for insurers to cover injectable PrEP, and unfortunately, many insurers do not cover it. There are financial assistance programs that may help to get injectable PrEP.

CDC, HIV Basics, PrEP. June 2022.
FDA, FDA Approves Second Drug to Prevent HIV Infection as Part of Ongoing Efforts to End the HIV Epidemic. October 2019.
FDA, FDA Approves First Injectable Treatment for HIV Pre-Exposure Prevention. December 2021.

PrEP is very effective when taken as prescribed.

According to the U.S Centers for Disease Control and Prevention (CDC), taking PrEP daily reduces the risk of getting HIV from sex by more than 99 percent. For people who inject drugs, PrEP also reduces the risk of getting HIV by 74 percent when taken consistently.

When you start taking the daily PrEP pill, it takes about 7 days to reach the maximum level of protection against HIV for anal sex and 21 days for vaginal sex or injection drug use. PrEP works less well when people don’t take it daily as prescribed.

Taking PrEP as a shot is also highly effective at preventing HIV though it is currently not recommended for people who inject drugs.

Both forms of PrEP do not protect against other sexually transmitted diseases (STDs). Condoms reduce the risk of gonorrhea, chlamydia, syphilis and other common STDs, as well as pregnancy.

CDC: HIV, Risk and Prevention. July 2022
CDC, HIV Basics, PrEP. June 2022.

Daily PrEP must be taken for some time before a potential exposure to HIV to be effective. According to the U.S. Centers for Disease Control and Prevention (CDC), PrEP reaches maximum protection against contracting HIV through receptive anal sex after about 7 days of daily use. For receptive vaginal sex and injection drug use, the CDC estimates that PrEP reaches maximum protection after about 20 days of daily use. Missing daily doses can lower PrEP’s effectiveness.

PrEP as an injectable:

According to the CDC, it is not yet known how long it takes for PrEP shots to reach maximum effectiveness during sex.

CDC, HIV Basics, PrEP. June 2022.
CDC, HIV Basics, PrEP Effectiveness. June 2022.

PrEP is approved for all adults and adolescents (weighing at least 77 pounds) who are at risk of contracting HIV. Some types of PrEP are only approved for anal sex. Talk with your healthcare provider about which type of PrEP is right for you.

The U.S. Centers for Disease Control and Prevention (CDC) recommends PrEP for those who have had anal or vaginal sex in the past six months and who have had:

  • A partner living with HIV, especially if that person has an unknown or detectable viral load. (This means either they are not on treatment for HIV or their treatment has not successfully suppressed their virus. People with HIV whose virus is undetectable, thanks to prescribed HIV treatment, cannot transmit it.)
  • Any sex partners whose HIV status is unknown, especially if any of the sex was condomless.
  • Has had a bacterial sexually transmitted disease (STD) in the past six months, including gonorrhea, chlamydia or syphilis. (However, for those who have receptive vaginal sex, chlamydia infection is not considered an indication that PrEP may be warranted.)

The CDC also recommends that people who may be at risk of contracting HIV in the future discuss this with a healthcare provider to see if PrEP is right for them.

If you’ve taken PEP:

People who have taken post-exposure prophylaxis (PEP), which is a month of medications started within 72 hours after a potential exposure to HIV, may also be good PrEP candidates. The CDC recommends that people who have taken PEP more than once consider PrEP.

People who inject drugs:

For people who inject drugs, the CDC recommends PrEP for those with an injection partner who has HIV or who have shared injection drug equipment with others within the past six months.

Planning a pregnancy:

If you and your partner are considering getting pregnant and one of you has HIV, PrEP can help you conceive a child without transmitting HIV. If the HIV-positive partner is on antiretroviral (ARV) treatment and has an undetectable viral load, they cannot transmit the virus through sex. If the HIV-negative partner takes PrEP, this can add another layer of protection.

Speaking with the healthcare provider:

Not all healthcare providers are knowledgeable about PrEP. Some may not know how to speak without judgment about sex or injection drug use. That said, there are many healthcare providers who specialize in serving populations who use PrEP.

CDC, HIV Basics, PrEP, June 2022.
CDC, Pre-Exposure Prophylaxis 2021 Update [PDF].

Tests. June 2022.

Federal law requires that almost all insurers cover PrEP in pill form. Insurers also cannot charge anything, such as copays or deductible payments, for the prescriptions. This means that both the medication and the routine clinic visits needed to maintain a prescription to PrEP in pill form must be totally free.

If you do not have insurance, there are financial assistance programs that may be able to help with the cost of the medication and the clinic visits.

Currently, injectable PrEP is not widely covered by insurers. However, there are financial assistance programs that may be able to help.

Tests, June 2022.

PrEP requires a prescription in most places. Any medical professional who can prescribe medications, including doctors and nurse practitioners, can prescribe PrEP.

If you don’t have a regular healthcare provider or they are reluctant to prescribe PrEP, there are organizations that can help you get on PrEP. This may include finding a provider and identifying sources of financial assistance if necessary.

While highly effective at protecting against HIV, PrEP does not protect against other sexually transmitted diseases (STDs). Condoms are a highly effective means of preventing transmission of HIV and many other STDs when used consistently and correctly. Condoms are the only method of protection that also prevents pregnancy and STDs.

If you are uninsured or under insured, there may be resources available that can help pay for PrEP and the necessary clinic visits and tests.

The U.S. Department of Health and Human Services’ Ready, Set, PrEP Program provides PrEP at no cost for people who do not have insurance.  As a staff member today about how to get PrEP.

Depending on your income, you may be eligible to get PrEP at no cost as part of a program offered by its manufacturers. Gilead Sciences’ Advancing Access Program may also be available to those on Medicare who don’t have Part D prescription drug coverage. To determine if you are eligible, your medical provider needs to submit an application for you.


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