Can you explain how one becomes resistnace to HIV medication? I understand if you stop taking the medication you may become reisistant but is there other ways --does having sex with different strains of the HIV make you resistant? Thanks for a great website

Tnanks for the compliment and the question.

The way HIV gets resistant is by being exposed to medication that is either not strong enough or at too low a dose to kill it. Anytime that the virus can grow in the presence of the medication, it has a chance to get resistant. Just stopping your meds may not be the main risk...but intermittent treatment with many missed doses sets up the situation for too low a blood level to effectively kill the virus. Likewise taking some of the meds, but not all (such as missing the night time dose but taking the morning dose, or stopping one med that may be causing a side effect while taking the rest) is worse than not taking any as far as resistance is concerned.

The other issue you raise is called "HIV superinfection". Since the immune system cannot effectively stop HIV in most people it is possible to catch HIV more than once. If you were exposed to a virus that had drug resistance it might be possible to catch it on top of the virus you currently have. Drug resistance has been spread in this way (mostly in people who are not taking meds).

Best, Joe