If you have had a high-risk exposure to HIV (e.g., unprotected sex with an HIV-positive person or someone with unknown status, sharing needles), HIV Post-Exposure Prophylaxis (PEP) is your emergency lifeline. PEP is a course of medication that can prevent HIV infection if taken as directed — but it must be started as soon as possible. Here’s everything you need to know about PEP:
What is PEP? PEP is a combination of antiretroviral drugs that work by blocking the HIV virus from establishing an infection in your body. It targets the virus in the early stages of exposure, before it can bind to your cells and start replicating. PEP is not a cure for HIV — it is a preventive measure, similar to taking emergency contraception after unprotected sex.
The 72-hour golden window: PEP is most effective when started within 72 hours (3 days) of high-risk exposure. The sooner you start, the higher the success rate. After 72 hours, the virus may have already started to establish an infection, and PEP becomes much less effective. However, even if you are between 48–72 hours (like 64 hours) after exposure, it is still worth taking PEP — it can still provide significant protection.
PEP success rates by time (based on medical research):
– Within 2 hours: Success rate nearly 99%
– 2–24 hours: 90–95% success rate
– 24–48 hours: Still above 85%
– 48–72 hours: Lower but still effective
How to get PEP: PEP is available by prescription from doctors, emergency rooms, sexual health clinics, or HIV clinics. You will need to explain your exposure (be honest about the details — this helps the doctor prescribe the right medication) and may need to take a baseline HIV test. PEP is not available over the counter, so you must see a healthcare provider as soon as possible.
Taking PEP: PEP must be taken every day for 28 days, at the same time each day — no missed doses, no stopping early. Missing doses or stopping early can lower the drug levels in your blood, making it easier for HIV to breakthrough. Common side effects of PEP include nausea, fatigue, dizziness, and headache — these are usually mild and go away after a few days. Do not stop taking PEP because of side effects — talk to your doctor, who can help manage them.
Follow-up after PEP: After finishing the 28-day course, you will need to get tested for HIV at 4 weeks, 8 weeks, and 12 weeks (3 months) after exposure. This is to confirm that PEP was effective. You should also avoid any further high-risk behavior during this time.
Remember: PEP is not a substitute for safe behavior, but it is a powerful tool for emergency prevention. If you have a high-risk exposure, do not wait — seek PEP immediately.