Phylodynamic analysis reveals changing transmission dynamics of HIV-1 CRF01_AE in Japan from heterosexuals to men who have sex with men

• Published in: International journal of infectious diseases Vol. 108; pp. 397 - 405
• Main Authors: Otani, Machiko, Shiino, Teiichiro, Kondo, Makiko, Hachiya, Atsuko, Nishizawa, Masako, Kikuchi, Tadashi, Matano, Tetsuro
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2021; Elsevier
• Subjects: AIDS; Cluster analysis; HIV-1; Japan; Men who have sex with men; Molecular epidemiology; HIV-1; Cluster analysis; Molecular epidemiology; AIDS; Japan; Men who have sex with men
• ISSN: 1201-9712; 1878-3511; 1878-3511
• DOI: 10.1016/j.ijid.2021.05.066

•CRF01_AE began to spread among MSM, with frequent cluster formations, in the 2000s.•CRF01_AE transmission risk has shifted from heterosexuals/IDUs to MSM since 2014.•Nevertheless, CRF01_AE transmissions among heterosexuals and IDUs have persisted.•Prevention measures need to target CRF01_AE in various populations in Japan. HIV-1 circulating recombinant form (CRF) 01_AE is the second major subtype in Japan. Our previous study indicated that CRF01_AE was predominantly circulating in heterosexuals/injecting drug users (IDUs). With implications of increased CRF01_AE infections among men who have sex with men (MSM), this study sought to investigate whether the transmission dynamics of CRF01_AE infections in Japan have changed. Sequences from 8032 newly diagnosed HIV-1-infected individuals were analysed. For 614 (7.6%) of CRF01_AE cases, clusters were identified and categorised by transmission risks. Median times to the most recent common ancestors (tMRCA) were estimated. The individuals were predominantly Japanese (64%) and male (72%). MSM became the predominant transmission risk from 2014. Thirty transmission clusters (TCs) and 48 pairs, including 40% of individuals, were identified. MSM were approximately five times more likely to be in a TC compared to heterosexuals, and were the major contributors to TCs. tMRCA data suggest that MSM TCs emerged from 1996 and became predominant around 2000. CRF01_AE has spread among MSM, with frequent and continuous cluster formations, and MSM has become the predominant transmission risk. Our study suggested that CRF01_AE transmission has shifted from heterosexuals/IDUs to MSM. Prevention measures targeting key populations should be considered for controlling CRF01_AE spread.