What Is PrEP (and How Does It Help Prevent HIV)?

Meet the drug that’s transforming HIV prevention.

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There’s no cure for HIV, or human immunodeficiency virus, so prevention has been an important focus for scientists and public health experts. For decades, most prevention efforts centered around educating the public about how HIV/AIDS can spread and how people can protect themselves from contracting and spreading the virus.

Continued progress in HIV research, however, has led to the introduction of an oral pill that works to prevent HIV from developing in the body. This pill, called pre-exposure prophylaxis (PrEP), helps prevent HIV in those who do not currently have HIV, but who may be at risk for contracting the virus, according to hematologist Jeffrey Laurence, MD, of Weill Cornell Medicine in New York City.

PrEP is a daily pill that stops HIV from multiplying in your body in the event that you are exposed to the virus. For PrEP to be effective, a person has to take PrEP every single day. That’s what makes PrEP different than a vaccine, which is administered, say, once and can then fight off an infection for several years. Learn more about how PrEP works here.

The risk of getting HIV through sex drops by about 99 percent among those who take PrEP consistently, according to the Centers for Disease Control and Prevention (CDC). Although that’s an impressive number, doctors still recommend using a condom every time for maximum protection against HIV, as well as preventing other sexually transmitted infections like gonorrhea and chlamydia. (PrEP also reduces the risk of HIV transmission by at least 74 percent for those who share needles.)

Taking PrEP is a safe way to prevent HIV and does not have many risks or serious side effects. Some people experience a bit of a nausea at first, which generally fades away. For those who have been taking PrEP for five years and do not have HIV, no significant health problems have been reported, according to the CDC.

If you think you’ve already been exposed to HIV, PrEP is not the best option. Instead, talk to your doctor about a treatment called post-exposure prophylaxis (PEP), which is meant as an emergency response than can prevent HIV infection if you take it within 72 hours after the potential HIV exposure.