PrEP and PEP explained

PrEP and PEP are two different ways of using HIV medicines to prevent infection. They're among the most effective prevention tools available.

PrEP: before exposure

PrEP (pre-exposure prophylaxis) is taken by HIV-negative people to prevent HIV. When taken as prescribed, it reduces the risk of getting HIV from sex by about 99%, according to the CDC. Options include daily pills and, in some places, long-acting injections. Some guidelines also support 'on-demand' dosing for certain people — a clinician will advise what's right.

• You'll need an HIV test before starting and regular tests while on it.
• Kidney function and other STIs are checked periodically.
• PrEP doesn't prevent other STIs, so condoms and testing still matter.

PEP: after exposure

PEP (post-exposure prophylaxis) is a 28-day course of HIV medicines started after a possible exposure — for example a condom breaking, sexual assault, or sharing needles. It must be started within 72 hours, and works best the sooner it's taken.

Who might consider PrEP

• People with HIV-positive partners who aren't virally suppressed.
• People who don't always use condoms with partners of unknown status.
• People recently diagnosed with an STI.
• Anyone who feels it would give them peace of mind.

Getting it

PrEP is available through sexual-health clinics, GPs, and online services in many countries, sometimes free. Ask a clinic what's available locally.