Molecular networks reveal complex interactions with MSM in heterosexual women living with HIV-1 who play peripheral roles in Guangzhou, China

Background: With the number of newly diagnosed HIV-positive heterosexual women increasing yearly, it is ur-gent to understand HIV-1 transmission among heterosexual women in Guangzhou, China.Methods: HIV-1 pol sequences were obtained from people living with HIV-1 during 2008 to 2017 in Guangzhou, China. A molecular network was constructed using HIV-1 TRAnsmission Cluster Engine with 1.5% genetic dis-tance. Potential linkage and centrality metric were measured with Cytoscape. Transmission pathways between heterosexual women and men who have sex with men (MSM) were determined using Bayesian phylogenetic analysisResults: In the network, 1799 (62.6%) MSM, 692 (24.1%) heterosexual men and 141 (4.9%) heterosexual women formed 259 clusters. Molecular clusters including MSM and heterosexuals were more likely to form larger net-works (P<0.001). Nearly half of the heterosexual women (45.4%) were linked to heterosexual men and 17.7% to MSM, but only 0.9% of MSM were linked to heterosexual women. Thirty-three (23.4%) heterosexual women linked to at least one MSM node and were in peripheral role. Compared to general heterosexual women, the proportion of heterosexual women linked to MSM infected with CRF55_01B (P<0.001) and CRF07_BC (P<0.001) was higher than that of other subtypes, and the proportion diagnosed between 2012 and 2017 (P = 0.001) was higher than that in 2008-2012. In MCC trees, 63.6% (21/33) of the heterosexual women differentiated from the heterosexual evolutionary branch, while 36.4% (12/33) differentiated from the MSM evolutionary branch.Conclusion: Heterosexual women living with HIV-1 were mainly linked to heterosexual men and were in pe-ripheral positions in the molecular network. The role of heterosexual women in HIV-1 transmission was limited, but the interaction between MSM and heterosexual women were complex. Awareness of the HIV-1 infection status of sexual partners and active HIV-1 detection are needed for women.