HIV-1 drug resistance in Thailand: before and after National Access to Antiretroviral Program.

Background: The Ministry of Public Health (Thailand), MoPH, has had a program called National Access to Antiretroviral Program for People who have AIDS (PHA) or "NAPHA", to offer free antiretroviral drugs (ARV), which are locally produced in Thailand, to any HIV-1 infected patients with CD4<200 since 2002. This program may increase usage of ARV therapy and the emergence of HIV-1 drug resistance.

Objectives: To monitor HIV-1 ARV drug resistant codon mutation in Thailand before and after the "NAPHA" program.