Does PrEP protect against other STIs? PrEP does not protect against other sexually transmitted infections (STIs) such as gonorrhea, chlamydia, herpes, or syphilis. This is why we still recommend condoms and getting tested regularly. Related articles What can I do if I am not in a state that Nurx serves, and my provider refuses to give me PrEP? Is PrEP safe to use during pregnancy? Are the cheaper generics any less safe or effective than the more expensive or brand name pills? I want to move the time that I take my pill. How do I do that? How effective is PrEP?