[Analysis on characteristics of HIV-1 molecular networks in men who have sex with men in Kunming, 2016-2018].

Objective

To analyze the characteristics of HIV-1 molecular network in men who have sex with men (MSM) from 2016 to 2018 in Kunming, Yunnan province, explore the risk factors associated with HIV-1 transmission network and provide evidence for the effective implementation of intervention.

Methods

A total of 540 samples of newly reported HIV-1 positive MSM were consecutively collected in Kunming from 2016 to 2018, the pol gene fragments were amplified by nested polymerase chain reaction (PCR). HIV-1 molecular networks were constructed according to the bootstrap value of the maximum likelihood evolutionary tree over 95% and the genetic distance less than 3%. The factors associated with the subjects entering network and network growth were further analyzed.

Results

Among 459 successfully sequenced samples, seven genotypes were found, in which CRF07_BC (49.2%, 226/459) and CRF01_AE (40.3%, 185/459 ) were predominant. Other genotypes included URFs (4.8%, 22/459), CRF08_BC (3.1%, 14/459), CRF55_01B (1.7%, 8/459), B (0.7%, 3/459) and CRF68_01B (0.2%, 1/459). A total of 163 sequences entered the network, with an entry rate of 35.5%(163/459), forming 56 clusters with the number of individuals in the cluster was between 2 and 13. The analysis of the factors associated with entering network showed that the MSM who married and had multiple homosexual partners were more likely to be found in HIV-1 molecular networks. Multivariate logistic regression analysis showed that the number of sexual partners was the factor for the growth of HIV-1 molecular network. According to the criteria for the emergence of three or more newly reported cases in every year, six transmission clusters were judged as active transmission clusters, in which MSM who were not Kunming natives, had sexually transmitted diseases (STD), were divorced and students were the key targets of intervention.

Conclusions

HIV-1 genotypes in MSM in Kunming were becoming complex, the risk factors associated with transmission networks in MSM in Kunming included being married and having multiple partners, the intervention targets in active transmission clusters included MSM who were not Kunming natives, had STD, were divorced and students. This study provided the basis for applying HIV-1 molecular networks to real-time intervention in this population.