If you have had sex with an HIV-positive person whose viral load is not below the detection limit (what is this) and the condom broke or was suddenly gone, i.e. you have taken a risk of infection, you have the option of taking post-exposure prophylaxis, known as PEP.
PEP must be started as soon as possible after the risk of HIV. Preferably within two hours, otherwise within 24 hours if possible, at the latest after 48 hours. Whether a PEP can still be useful up to 72 hours (three days) after the accident is disputed.