Post-exposure prophylaxis should ideally be started within how many hours of exposure?

• A. 24 hours
• B. 72 hours
• C. 96 hours
• D. 120 hours

Answer: (B)

Post-exposure prophylaxis is a short course of antiretroviral meds given after a potential HIV exposure to prevent the virus from establishing infection. The key is to start treatment early, because the virus begins to take hold in the first few days. The practical window for starting PEP is within 72 hours of exposure. Initiating within this period significantly lowers the risk of infection, while delaying beyond 72 hours makes the benefit much less certain. So, the recommended timeframe is up to 72 hours after exposure, with earlier initiation offering the best chance of prevention.