A13 HIV drug resistance over a decade of antiretroviral therapy scale-up for HIV/AIDS patients in Vietnam

Since 2005, Vietnam has remarkably scaled-up Antiretroviral therapy (ART) for HIV-infected people. The number of people receiving ART has increased from 2,670 in 2005 to 78,438 adults and 4,204 children at the end of 2013. ART coverage increased to 67% (60.0% in adults and 78.1% in children), against current eligibility criteria per National Guideline (CD4 cells <350 cells/ml). Standardized ART was delivered at 364 outpatient clinics at the end of 2013. Since 2010, the Ministry of Health has recommended the first-line prioritized ART regimens with two NRTIs (d4T + 3TC or ZDV + 3TC) plus one NNRTI (nevirapine [NVP]). In the context of rapid ART scale-up, the extent of HIV drug resistance (HIVDR) in Vietnam has been concerned, studies on transmission and emergence of HIV drug resistance were carried out in 2013–4. HIVDR study protocols were adapted from WHO guidelines for transmitted drug resistance (TDR) (2012) and acquired drug resistance (ADR) (2014). In brief, the TDR survey was implemented in a total of 15 voluntary counseling and testing (VCT) sites located in the old Hanoi. A total of 74 eligible VCT clients, aged 18–24, detected HIV positive, had no history of ART exposure, had no previous pregnancy if female, and were sequentially sampled. HIV genotyping was done in order of enrollment date until DR prevalence could be classified. For the ADR survey, 8 ART outpatient clinics were sampled from a total of 114 clinics that had ART available for more than 3 years up to the end of 2010, in the North, using probability proportional to proxy size (PPPS) sampling method. From each selected VCT, 23 patients who had received ART for more than 36 months were consecutively recruited into the study. All patients were taken blood for evaluating viral suppression and HIV drug resistance if viral load above 1,000 copies/ml. The prevalence of transmitted HIV drug resistance was classified as moderate between 5 and 15%, mainly to NRTIs/NNRTIs, no protease inhibitor (PI) resistance. In 181 patients on ART for more than 36 months, 93.9% (95% CI: 90.4–97.4%) had viral load suppression and 5.5% (95% CI: 2.2–8.9%) had drug resistance. Notably, 100% of individuals with viral suppression failure are resistant to all drugs in both their initial and current ART regimes receiving. Against 7 NRTIs and 4 NNRTs recommended for the first-line ART as per the national guideline, resistance rates ranged between 75 and 100%. No resistance to PIs was found. The most common mutations are M184V (90%), D67G (60%), K70RES (60%), K103N (50%), Y184C (50%), T215FYN (50%), and K219QE (50%). The scaled-up ART program in Vietnam was proven to be effective with high rate of viral suppression at 36 months on the first-line prioritized ART regimens. Transmitted HIV DR to NRTIs/NNRTIs was increased, requiring the national program on HIV DR surveillance and prevention be strengthened to maximize long-term effectiveness of first-line ART regimens.