Guides

PrEP and drug resistance

If you take PrEP correctly, the chance of drug resistance is very low.

Firstly, resistance relates to HIV and not the person. So an HIV negative person can’t be drug resistant. Secondly, resistance is only a risk if you become HIV positive. Even then the risk is low.

The risks of drug resistance are from:

  • Starting PrEP without knowing that you are already HIV positive. This is why the HIV test before PrEP is essential.<
  • Becoming HIV positive during a break from PrEP and then not having an HIV test before restarting. 
  • Missing too many PrEP doses, so that drug levels are too low to prevent HIV infection.
  • Contact with drug-resistant HIV. This is very rare: globally, only a few cases have been reported of PrEP not working because of drug-resistant HIV.

Last updated: 1 November 2019.