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

Abstract

Background: 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. Methods: 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. Results: 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. Conclusions: 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.

Reconstructing the phylodynamic history and geographic spread of the CRF01_AE-predominant HIV-1 epidemic in the Philippines from PR/RT sequences sampled from 2008-2018

“…In the HIV epidemic in China, the infection route of sexual contact was found to be more likely to be an infection with CRF01_AE compared to contaminated needles, showing that specific transmission routes and risk-groups can be dominated by a specific subtype [59]. Transmission in the MSM risk-group was also found to more likely form clusters [60] and has been linked to more occurrences of superspreaders than in non-MSM risk groups [61], [62]. Finally, it is also possible for a combination of multiple factors to have contributed to the predominance of CRF01_AE in the Philippines.…”

Epidemiological characteristics of HIV transmission in southeastern China from 2015 to 2020 based on HIV molecular network

“…During the investigation and tracking of the transmission process of HIV-1 in MSM, conventional epidemiological tools based on questionnaire surveys and peer tracking may have various biases, resulting in low credibility of conclusions and subsequent unfavorable follow-up and behavioral interventions. Recently, HIV-1 molecular transmission networks using the viral gene sequences of infected individuals has gradually been employed to accurately identify potential transmission and determine active transmission networks, thus facilitating targeted intervention measures(34)(35)(36)(37)(38).…”