This is related to the question of the writer who asked if he should "Ditch the Nukes". Isn't resistance a matter of degree, so that if HIV has resistance to AZT, for example, depending on the level of that resistance, AZT might still have some effectiveness, even though it isn't as effective as before? Also, if you have resistance to 3TC, isn't it better to keep that drug in the regimen as 3TC-resistant virus is less fit than wild-type?

Thank you

Thank you for your post and great questions/comments. You are absolutely correct that resistance can vary from none, a little or a lot. It does appear that even in the face of resistance NRTIs may contribute to viral suppression. This has best been shown with 3TC and I agree that in the setting of multidrug resistant virus most people would continue 3TC (or FTC) as part of the next regimen. This is probably because of some positive effects on fitness as well as potentially continued antiviral activity of the drug and how it influences susceptibility to other durgs, such as increasing sensitivity to AZT and tenofovir.

Best, Eric