How effective is PrEP?

PrEP is most effective upon daily usage as research suggests.

As suggested by the IPREX clinical trial, the protection increases when the therapy is consistent.

Protection for a male to male sex was 99% effective when patients took the drug on a daily basis for one week.

For participants in this trial that took PrEP 4 times per week the protection was 96%.

While participants that took the medication only twice a week the protection dropped to 76%.

Obviously, there is an additive protective power for taking prep every day. This additive power has minor statistical significance. However, it increases the safety margins of the regimen. Forgetting to take the medication for one or 2 days in this regimen is not so dangerous as with the 4-day regimen.

Protection drops significantly if PrEP is taken for less than 4 days.

As for needle injection transmission, the research suggests that prep can be protective in 74% of the cases.

For more information, Check Our guide on How to take PrEP, Step 3.