High levels of transmitted drug resistance to INSTIs and NNRTIs in Chile: A nationwide prevalence study.

BACKGROUND

Human Immunodeficiency Virus (HIV) morbi-mortality and transmission have decreased due to antiretroviral therapy (ART). However, treatment failure still occurs when acquiring a strain with resistance mutations. HIV transmitted drug resistance (TDR) is increasing worldwide, and its prevalence in Chile was estimated at 10.4 % in 2018. We aimed to determine the prevalence of TDR and, its associated mutations to evaluate the need to incorporate genotyping studies in ART-naïve people living with HIV in Chile.

METHODS

Cross-sectional study conducted in eleven health centers and seven regions in Chile. Participants were ≥ 18 years with a recent (≤12 months) HIV diagnosis, without previous ART exposure. Genotyping of the reverse transcriptase, protease, and integrase was performed using nested polymerase chain reaction followed by Sanger sequencing.

RESULTS

Between February 2023 and May 2024, 168 participants were recruited. The mean age was 35.9 years (range 18-78), 89.3 % were Chilean, and 84.5 % were male. TDR overall prevalence was 16.7 %, and the percentage of TDR by family was 3 % for nucleoside reverse transcriptase inhibitors (NRTIs), 7.1 % for non-nucleoside reverse transcriptase inhibitors (NNRTIs), 0.6 % for protease inhibitors (PIs) and 8.9 % for integrase strand transfer inhibitors (INSTIs). TDR for first-generation INSTIs was 11.9 % and 1.2 % for second-generation INSTIs.

CONCLUSION

TDR prevalence in Chile has increased and main affected families are first-generation INSTIs and NNRTIs. This result highlights the relevance of initiating ART with second-generation INSTIs or PIs, or incorporating baseline genotyping studies when initiating ART with NNRTIs or first-generation INSTIs.