Accumulation of HIV-1 Drug Resistance in Patients on a Standard Thymidine Analogue-Based First Line Antiretroviral Therapy after Virological Failure: Implications for the Activity of Next-Line Regimens from a Longitudinal Study in Mozambique.

We describe the accumulation of HIV-1 drug resistance and its effect on the activity of next-line components in patients with virological failure (HIV-1 RNA >1000 copies/mL) after 1 year (t1) of first-line antiretroviral therapy (ART) not switching to second-line drugs for one additional year (t2) in low-middle income countries (LMIC).