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LARGE HEPATITIS C TRANSMISSION CLUSTER
IDENTIFIED AMONG HIV POSITIVE MSM IN BANGKOK
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CROI 2020
Reported by Jules Levin
Win Min Han1, Donn J. Colby1,2,3, Apichaya Khlaiphuengsin4, Tanakorn Apornpong1, Stephen J. Kerr1, Sasiwimol Ubolyam1, Eugène Kroon1, Nittaya Phanuphak1, Anchalee Avihingsanon1, Kiat Ruxrungtham1, Praphan Phanuphak1, Pisit Tangkijvanich41 Thai Red Cross AIDS Research Centre, Bangkok, Thailand 2 Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
3US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA 4 Chulalongkorn University, Bangkok, Thailand
Abstract
A rapidly emerging HCV outbreak has recently been observed among HIV-positive men who have sex with men (MSM) living in Bangkok, Thailand. Little is known regarding the transmission networks among this population.
MSM with both acute (Feibig stages 1 to 5) and chronic HIV infection and with incident HCV infections were identified in research cohorts at the Thai Red Cross AIDS Research Centre. Incident HCV infections were defined as seroconversion from anti-HCV antibody negative to positive after initiating ART. NS5B regions of the HCV genome (404 and 471 bps) were amplified using nested-PCR and sequenced. Phylogenetic inference was constructed by Maximum Likelihood methods in MEGA X.0.5 software with 1000 bootstrap samplings. Clusters were identified using ClusterPicker with support and genetic distance thresholds of 85% and of 4.5%, respectively.
A total of 48 (25 acute HIV and 23 chronic HIV) MSM with incident HCV infection and amplifiable NS5B sequences were included in the analysis. Median (interquartile range, IQR) HCV RNA was 6.3 (5.3-6.9) IU/mL. HCV genotype (GT) was 85% GT 1a and 15% GT 3a or 3b. Median age at HCV diagnosis was 34 (IQR, 28-41) years. 83.3% (40/48) had history of syphilis infection and 36% (16/44) reported crystal methamphetamine use. Only 2 (4%) reported ever injecting drugs, both crystal methamphetamine. Six (12.5%) were HBV co-infected, all of whom had chronic HIV. In the phylogenetic clustering analysis, 83% belonged to one of two clusters: one large (n=36, 75%) and one small (n=4, 8%) cluster (Figure). All clusters were GT 1a. Overall mean genetic distance was 0.10 (SE=0.02). Participants with acute HIV infection were more likely to be in a cluster (92%) than those with chronic infection (74%).
Phylogenetic analysis showing a high degree of clustering confirms that the HCV epidemic in the HIV-infected MSM community in Bangkok is recent and rapidly expanding. This epidemic is independent of past HCV transmission among people who inject drugs in Thailand, which was largely GT 3. Crytal methamphetamine use is high in participants with HCV infection, and previous reports have identified chemsex and group sex parties as factors associated with HCV transmission. HCV antibody testing should be regularly performed for MSM on ART in Bangkok, and direct-acting antivirals being offered to all MSM with HCV infection might contain this HCV epidemic from spreading further.
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