LAUSR

BACKGROUND College students are disproportionately affected by HIV-1 in China. However, little is known about the genetic characteristics of HIV-1 among this population. METHODS A molecular epidemiological investigation was conducted among the newly diagnosed antiretroviral therapy-naïve HIV-1-infected individuals during 2015-2019 in Nanjing city, China. The pol fragment (HXB2: 2,253-3,311) was obtained by HIV-1 RNA extraction and gene amplification, and subjected to genotyping, recombination analysis, and phylogenetic inference. RESULTS A total of 945 pol sequences from 226 students and 719 non-students were successfully amplified. Multiple genotypes were identified in students, including CRF01_AE (37.66%), CRF07_BC (32.90%), CRF55_01B (5.63%), CRF68_01B (3.46%), CRF67_01B (3.03%), subtype B (1.73%), CRF58_01B (1.30%) and URFs of 01C_like (7.08%), 0107_like (3.98%), 01BC_like (2.21%), and 01B_like (1.33%). The distribution of genotypes among students was similar to that among non-students. The estimated mean evolutionary rate of URFs was 2.89 × 10-3 [95% Bayesian credible interval (BCI): 1.89-3.90] nucleotide substitutions/site/year. Approximately 64% (21/33) of URFs among students were located in three major clusters (0107_like, 01C_like 1 and 01C_like 2 clusters), which had recent tMRCAs and low mean genetic distance, and presumably originated from Nanjing (PP ≥ 0.99, state probability ≥ 0.9). Among 226 students with pol segments, the prevalence of primary and transmitted drug resistance mutations was 15.93% and 3.98%, respectively. CONCLUSIONS The rapid evolution of multiple HIV-1 genotypes and high prevalence of URFs circulating among students in Nanjing emphasized the necessity of comprehensive surveillance for HIV-1 transmission among this population.