If you have had sex with an HIV-positive person whose viral load is not undetectable and the condom broke or was missing – that is, if you were at risk of infection, you have the option of taking post-exposure prophylaxis, also called PEP.
PEP must be started as soon as possible after an HIV risk. Preferably within two hours, otherwise preferably within 24 hours, at the latest after 48 hours. Whether PEP can still be useful up to 72 hours (three days) after the accident is controversial.