If you are not on prep, and have been exposed to HIV by having condomless sex with a person who was HIV-positive (and you don't know if they had an undetectable viral load), or whose HIV status you don't know, contact your healthcare provider as soon as possible to talk to them about taking PEP to precent a possible HIV infection. You need to start taking it no more than three days after an exposure in order for it to work. Continue taking it for 28 days, and use condoms until you're sure you haven't been infected. If you have HIV and think there's a chance you've exposed someone else, you can tell that person about PEP.
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