How well does PrEP work?

Click the links below for detailed answers to questions people ask about how well PrEP works.

• How effective is PrEP at preventing HIV?
• How effective is PrEP compared to condoms?
• If I use PrEP, do I have to use condoms?
• How soon after starting PrEP will I be protected? How long do I have to keep taking it to maintain that protection?
• Does taking PrEP mean I can’t get HIV?
• Has anyone ever contracted HIV despite taking PrEP as directed?
• When people say PrEP is 99% effective, what does that mean? Do I still have a 1% chance of contracting HIV?
• Does PrEP protect against both HIV-1 and HIV-2?
• What about Truvada-resistant strains of HIV?
• Can I be an "HIV carrier" while I am HIV-negative?
• What about the Truvada lawsuit ads I'm seeing all over?