HIV is a virus that affects the immune system. There are several ways to prevent contracting HIV.
One prevention method is called postexposure prophylaxis (PEP), which is a combination of antiretroviral medications. PEP can be taken after a potential exposure in order to help prevent HIV transmission.
The article below will focus on what exactly PEP is, when and how to take it, and what to expect.
PEP is taken in emergency situations when exposure to HIV may have occurred. When taken as directed, it’s effective at preventing HIV transmission. Some examples of situations where PEP may be used include after:
- engaging in consensual sex, especially without a condom or other barrier method or if a barrier method breaks
- experiencing a sexual assault
- sharing needles or other injection drug equipment
- having an occupational injury, such as a needlestick or a cut
It’s important to note that PEP is for emergency use only. It’s not a substitute for other HIV prevention methods, such as using a condom or other barrier method during sex or taking preexposure prophylaxis (PrEP).
PEP is actually a combination of different antiretroviral drugs. These drugs work to prevent the virus from replicating effectively in the body. The
- tenofovir/emtricitabine (Truvada) with raltegravir (Isentress)
- tenofovir/emtricitabine (Truvada) with dolutegravir (Tivicay)
HIV can be transmitted through body fluids containing the virus, such as blood, semen, and fluids from the vagina or rectum. These must make direct contact with blood or mucous membranes, such as those found around the genitals and mouth, in order to transmit the virus.
There are several ways to reduce the risk of contracting HIV including:
Because of this, it’s vital to talk with a healthcare professional as soon as possible if exposure to HIV may have occurred. This can include speaking with someone at:
- a primary care office
- an urgent care facility
- a sexual health clinic
- the emergency room
PEP medications are taken daily for a total of 28 days (4 weeks). They’re given in a pill format.
It’s important to take PEP around the same time each day. This is so the level of antiretroviral drugs in the body remains constant during treatment.
Missing doses of PEP can make it less effective. It may be helpful to set a daily alert on a phone or tablet to remember when it’s time for another dose. When missing one dose in a 24-hour period, it can be taken as soon as someone notices.
Remember that PEP can’t reduce the risk of other STIs or infections like hepatitis C. It also can’t prevent additional HIV exposures. Because of this, someone taking PEP should continue to use condoms during sex and avoid sharing injection drug equipment.
Now that we’ve discussed PEP as well as how and when it’s taken, let’s take a look at what to expect both before and after taking PEP.
Prior to prescribing PEP, a healthcare professional will perform an assessment to determine the risk of exposure to HIV. The following situations are considered to increase the risk of HIV transmission:
- Body fluids that may contain HIV — such as those of someone who is HIV-positive or has an unknown HIV status — had direct contact with the bloodstream or mucus membranes.
- An individual isn’t currently taking PrEP as directed by their doctor in order to prevent HIV.
A healthcare professional will also request rapid HIV testing before prescribing PEP. PEP isn’t recommended for people that are HIV-positive, and it’s estimated that 1 in 7 people that have HIV don’t know that they have it.
Other tests that may be ordered include:
- screening for other STIs, such as syphilis, gonorrhea, and chlamydia
- screening for other bloodborne infections, such as hepatitis B and hepatitis C
- a pregnancy test
- blood tests to check kidney and liver function
After completing a course of PEP, it’s important to get tested for HIV. This can help determine if PEP was effective.
Plan to get tested right after finishing PEP treatment and again 3 months after the initial exposure. People who contracted hepatitis C during a potential HIV exposure will need an additional HIV test 6 months after the exposure.
While PEP isn’t 100-percent effective, there are very few reports of HIV transmission when it’s used as prescribed. Let’s look at what some of the research says.
Of this number, only 17 people (about 1 percent) went on to contract HIV. Researchers noted that contracting HIV after PEP was associated with factors like starting PEP more than 72 hours after exposure or not taking PEP as directed.
A 2016 analysis by the Centers for Disease Control and Prevention (CDC) looked at studies of PEP that covered different groups:
- Men who have sex with men. From six studies, 48 out of 1,535 men contracted HIV after PEP. Out of this number, only 8 cases (0.5 percent) may have been due to PEP not working. The other 40 were attributed to other behaviors.
- Mixed populations. In 15 studies, which included exposures through sex, sexual assault, and injection drug use, only 19 out of 2,209 people got HIV after PEP. Just 1 case was attributed to PEP not working while the other 18 were associated with other behaviors or not taking PEP as directed.
What may limit the effectiveness of PEP?
PEP is typically very effective at preventing HIV transmission when taken exactly as directed. PEP is less effective when:
- waiting more than 72 hours to start PEP after a potential exposure
- not sticking with the treatment plan
- engaging in behaviors that increase risk of HIV transmission
- exposure to a strain of HIV that’s resistant to the drugs in PEP
Some people that take PEP may experience side effects. These can include:
In the event of side effects, it’s important not to stop taking PEP, as this can make it less effective. Instead, speak to a healthcare professional about ways to reduce side effects.
A complete course of PEP can cost from
In some cases, an individual may not need to pay for PEP. For example, if a healthcare professional is exposed to HIV at work, their workplace insurance plan or worker’s compensation program typically pays for PEP.
In cases of sexual assault, the cost of PEP may be partially or completely covered. Survivors can reach out to the Office for Victims of Crime to learn about options in their state.
How to pay for PEP
Use the resources below to get help paying for PEP:
- Patient assistance programs. Many pharmaceutical companies have patient assistance programs that offer low-cost or no-cost medications to eligible individuals. Some to check out are:
- Medicine Assistance Tool. The Medication Assistance Tool helps people find programs that can help them get prescriptions at low cost or no cost. Enter the relevant medications and some basic personal information to get started.
- Medicaid. Medicaid is a joint federal and state program that helps to cover healthcare costs for people with low income and resources. Coverage and eligibility can vary by state.
PEP is a combination of antiretroviral drugs taken after a potential HIV exposure. It’s only used for emergency purposes and isn’t a substitute for other methods of HIV prevention.
When taken exactly as directed, PEP is very effective at reducing the risk of contracting HIV. PEP must be taken every day for a total of 28 days, ideally at the same time each day.
PEP is only effective when started within 72 hours of a potential exposure and it’s more effective the sooner an individual seeks treatment. In the event of a potential HIV exposure, don’t hesitate to see a healthcare professional about PEP.