Pre-exposure prophylaxis, commonly known as PrEP, is a medication regimen designed to prevent HIV infection in individuals who are HIV-negative. This highly effective intervention involves taking a daily pill or receiving a long-acting injectable. PrEP works by stopping the Human Immunodeficiency Virus (HIV) from establishing a permanent infection in the body if an exposure occurs.
PrEP Use Beyond Specific Populations
PrEP is a prevention tool for any HIV-negative individual at substantial risk of acquiring HIV, regardless of sexual orientation. While often associated with specific populations, PrEP is recommended for heterosexual individuals when circumstances indicate a risk of HIV acquisition. Risk for heterosexual individuals centers on behavior and specific situations.
Heterosexual individuals may be at risk for HIV through several pathways. A significant risk factor is having a sexual partner living with HIV, especially if that partner is not on effective HIV treatment and has a detectable viral load. Engaging in condomless anal or vaginal intercourse with an HIV-positive partner or a partner of unknown HIV status also presents a risk. This applies even in situations where conception is planned with an HIV-positive partner.
Additional risk factors include having multiple sexual partners, particularly if their HIV status is unknown. A history of sexually transmitted infections (STIs) within the past six months can also indicate an elevated risk. Engaging in sex without condoms in areas where HIV prevalence is high, or during periods of increased risk behavior such as with alcohol or recreational drug use, can increase vulnerability.
Understanding PrEP’s Mechanism and Efficacy
PrEP operates by preventing HIV from replicating within the body. The medication contains antiretroviral drugs that interfere with key enzymes the virus needs to reproduce. By blocking these processes, PrEP ensures that even if HIV enters the body, it cannot establish a permanent infection.
The effectiveness of PrEP is high when taken consistently as prescribed. For preventing HIV from sexual contact, daily oral PrEP reduces the risk by about 99%. In individuals who inject drugs, PrEP reduces the risk by at least 74%. Achieving maximum protection requires adherence; for receptive anal sex, it takes approximately seven days of consistent daily use, while for receptive vaginal sex and injection drug use, it typically takes about 21 days.
PrEP provides protection specifically against HIV. It does not prevent other sexually transmitted infections (STIs) such as gonorrhea, chlamydia, or syphilis. Therefore, combining PrEP with other prevention methods, like condoms, is recommended to reduce the risk of acquiring STIs. This comprehensive approach offers broader sexual health protection.
Considerations for Starting PrEP
Initiating PrEP involves several important steps to ensure it is safe and appropriate. Before starting PrEP, an individual must undergo an HIV test to confirm they are HIV-negative. Taking PrEP when already HIV-positive can lead to the development of drug-resistant HIV. A healthcare provider will conduct an HIV test.
Once on PrEP, regular follow-up appointments and testing are essential for ongoing monitoring. These appointments, usually every three months for oral PrEP, include repeat HIV testing to confirm continued HIV-negative status. Healthcare providers also monitor kidney function, often through blood tests, as some PrEP medications can affect the kidneys. Screening for other sexually transmitted infections is also performed.
Some individuals may experience common, mild side effects when starting PrEP, such as nausea, headache, diarrhea, or stomach pain. These side effects often resolve over time as the body adjusts to the medication. Discussing risk factors and medical history with a healthcare provider is necessary to determine if PrEP is the right prevention strategy.