Post-Exposure Prophylaxis (PEP) is a short course of antiretroviral medications taken soon after a potential exposure to HIV. It aims to prevent HIV infection from establishing itself. PEP is an emergency measure and must be started within 72 hours of exposure for best outcomes. The regimen involves taking these medicines daily for 28 days.
How PEP Works
PEP works by interfering with the human immunodeficiency virus (HIV) life cycle. Antiretroviral drugs target viral replication, preventing the virus from making copies. This stops the virus from establishing a permanent infection.
When taken, medications quickly enter the bloodstream and reach various tissues. By inhibiting viral replication, the drugs allow initially infected cells to die off without producing more HIV. This clears the virus before it can widely spread.
Understanding Transmission Risk While Taking PEP
While PEP is effective at preventing HIV infection, it does not immediately eliminate the possibility of transmitting the virus to others. HIV status remains unknown during the entire 28-day course of PEP and for a period afterward. Therefore, individuals on PEP should assume they could potentially transmit HIV until their status is definitively confirmed as negative.
The effectiveness of PEP relies on consistent adherence to the regimen. Missing doses or further potential exposures during the PEP course can reduce its efficacy. If the PEP regimen does not prevent infection, the individual could still acquire HIV, making them potentially able to transmit the virus.
Determining HIV Status After PEP
Confirming HIV status after completing a PEP regimen involves specific tests. Before starting PEP, a baseline HIV test ensures the individual is not already HIV positive. After the 28-day medication course is finished, follow-up testing is essential to determine if the prevention was successful.
Healthcare providers recommend HIV testing at 4 to 6 weeks, 3 months, and 6 months after the initial exposure. Fourth-generation antigen/antibody combination tests are commonly used. The 6-month mark is important because PEP medications can delay the body’s production of HIV antibodies, which could lead to a false-negative result if tested too early.
Protecting Others During PEP Treatment
Individuals undergoing PEP treatment should take precautions to protect others from potential HIV transmission. Until a definitive negative HIV status is confirmed through follow-up testing, it is important to act as if transmission is possible.
Recommendations include consistently using condoms for all sexual activity. Additionally, individuals should avoid sharing needles or syringes if injecting drugs. Temporarily refraining from donating blood, plasma, or organs is also advised. These measures are important steps to prevent any potential spread of HIV while awaiting conclusive test results.