High Level of Pretreatment and Acquired Human Immunodeficiency Virus Drug Resistance in El Salvador: A Nationally Representative Survey, 2018-2019

Abstract

Background: Human immunodeficiency virus drug resistance (HIVDR) can negatively impact the effectiveness of antiretroviral therapy (ART). We aimed to estimate the prevalence of pretreatment HIVDR (PDR) among ART initiators and the prevalence of viral load (VL) suppression and acquired HIVDR among individuals receiving ART for 12 ± 3 months (ADR12) and ≥48 months (ADR48) in El Salvador.

Methods: Nationally representative cross-sectional PDR, ADR12 and ADR48 surveys were conducted among adults with HIV from October 2018 to August 2019, following World Health Organization-recommended methods. Demographic and clinic data and blood specimens were collected.

Results: Two hundred sixty participants were enrolled in the PDR survey, 230 in ADR12 and 425 in ADR48. Twenty-seven percent (95% confidence interval [CI], 17.1%-39.9%) of ART initiators had PDR to efavirenz or nevirapine. The prevalence of VL suppression was 88.8% (95% CI, 83.1%-92.8%) in ADR12 and 80.5% (95% CI, 76.6%-84.0%) in ADR48 surveys. Among people with HIV receiving a first-line nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART regimens and with unsuppressed VL, the prevalence of ADR to efavirenz or nevirapine was 72.0% (95% CI, 32.3%-93.3%) and 95.0% (68.5%-99.4%) in the ADR12 and ADR28 surveys, respectively. ADR12 to boosted protease inhibitors (PI/r) or integrase strand transfer inhibitors (INSTIs) was not observed. ADR48 was 1.3% (95% CI, 0.2%-9.6%) and 2.1% (0.3%-13.7%), respectively.

Conclusions: Programmatic improvements in ART delivery are urgently needed in El Salvador to address the high levels of resistance to efavirenz or nevirapine among ART initiators and the low VL suppression prevalence among individuals on treatment.

Keywords: Central America; El Salvador; HIV; WHO; drug resistance surveillance.

Figure 1.

Phylogenetic tree and clustering. A, Sequences from 286 individuals included in the pretreatment drug resistance and acquired drug resistance surveys were included in the analysis. Reference human immunodeficiency virus (HIV) type 1 sequences of different subtypes obtained from the Los Alamos HIV Database were also included. Sequences were aligned by codon using ClustalW on Mega v6 after removing codons associated with HIV drug resistance according to the Stanford HIVdb tool (v8.9). A maximum likelihood tree was constructed based on the Tamura-Nei model with 1000 bootstrap repetitions. Using HIV-TRACE, putative transmission links were defined between individuals whose HIV sequence had a genetic distance <1.5%. Sequences forming clusters are shown in bold in the tree. Putative transmission links are detailed by drug resistance (B), age (C), and state of residence (D). Abbreviations: ADR, acquired drug resistance; F, female; M, male; NNRTI, nonnucleoside reverse transcriptase inhibitor; NRTI, nucleoside reverse transcriptase inhibitor; PDR, pretreatment drug resistance; PI, protease inhibitor; PR-RT, protease–reverse transcriptase.