Increase in HIV-1 transmitted drug resistance among untreated 16~25-y-old youths in the China-Myanmar border areas during 2009~2017

Background Transmitted drug resistance (TDR) can affect antiretroviral therapy (ART) efficacy. Surveillance drug resistance mutations in untreated youths newly reported with HIV-1 are highly representative of local TDR. We investigated HIV-1 TDR, TDR transmission based on molecular networks, and the effect of TDR mutations (TDRMs) on the CD4 count among youths in the China-Myanmar border area near the "Golden Triangle" to better understand TDR and guide ART.Methods From 2009 to 2017, 573 ART-naïve youths (16~25 y) newly reported with HIV-1 were enrolled. CD4 counts were obtained from whole blood. HIV pol gene sequences were amplified from RNA extracted from plasma. The Stanford REGA program and phylogenetic trees were used to determine genotypes. TDRMs were analyzed using the Stanford Calibrated Population Resistance tool. TDR transmission was evaluated from molecular networks of HIV-1 pol genes.Results The average prevalence of TDR was 6.3%, and the resistance to NNRTIs, NRTIs, and PIs was 3.49%, 2.62%, and 0.52%, respectively. TDR prevalence increased significantly during the period 2009~2017 (3.92%~9.48%, p<0.05). The mean CD4 count was significantly lower among individuals with TDRMs (373/mm3 vs. 496/mm3, p=0.013). The rate of network entry of youths harboring TDRMs (63.89%) was significantly higher than that of youths without TDRMs (44.9%).Conclusions The HIV-1 TDR increase and low CD4 count of patients with TDRMs in Dehong at the China-Myanmar border suggest the need for early ART and completion of resistance testing before initiating ART in HIV hotspots. Youths with TDRMs are likely to have links to others, necessitating intervention in onward transmission.