Abstract
Hepatitis C virus (HCV) is a genetically diverse pathogen infecting approximately 2–3% of the world's population. Herein, we describe results of a large, multicentre serological and molecular epidemiological study cataloguing the prevalence and genetic diversity of HCV in five regions of Vietnam; Ha Noi, Hai Phong, Da Nang, Khanh Hoa and Can Tho. Individuals (n = 8654) with varying risk factors for infection were analysed for the presence of HCV Ab/Ag and, in a subset of positive specimens, for HCV RNA levels (n = 475) and genotype (n = 282). In lower risk individuals, including voluntary blood donors, military recruits and pregnant women, the prevalence of infection was 0.5% (n = 26/5250). Prevalence rates were significantly higher (p<0.001) in intravenous drug users (IDUs; 55.6%, n = 556/1000), dialysis patients (26.6%, n = 153/575) commercial sex workers (CSWs; 8.7%, n = 87/1000), and recipients of multiple blood transfusions (6.0%, n = 32/529). The prevalence of HCV in dialysis patients varied but remained high in all regions (11–43%) and was associated with the receipt of blood transfusions [OR: 2.08 (1.85–2.34), p = 0.001], time from first transfusion [OR: 1.07 (1.01–1.13), p = 0.023], duration of dialysis [OR: 1.31 (1.19–1.43), p<0.001] and male gender [OR: 1.60 (1.06–2.41), p = 0.026]. Phylogenetic analysis revealed high genetic diversity, particularly amongst dialysis and multi-transfused patients, identifying subtypes 1a (33%), 1b (27%), 2a (0.4%), 3a (0.7%), 3b (1.1%), 6a (18.8%), 6e (6.0%), 6h (4.6%), 6l (6.4%) and 2 clusters of novel genotype 6 variants (2.1%). HCV genotype 1 predominated in Vietnam (60%, n = 169/282) but the proportion of infections attributable to genotype 1 varied between regions and risk groups and, in the Southern part of Vietnam, genotype 6 viruses dominated in dialysis and multi-transfused patients (73.9%). This study confirms a high prevalence of HCV infection in Vietnamese IDUs and, notably, reveals high levels of HCV infection associated with dialysis and blood transfusion.
Highlights
Hepatitis C virus (HCV) has been estimated to infect approximately 2–3% of the world’s population, with highest prevalence rates occurring in low and middle income regions including Africa and Southeast Asia [1,2,3,4]
This study confirms a high prevalence of HCV infection in Vietnamese intravenous drug user (IDU) and, notably, reveals high levels of HCV infection associated with dialysis and blood transfusion
Prevalence of HCV Infection in Vietnam In a sample of 5250 individuals considered to be at low risk for infection the prevalence of HCV was 0.5%
Summary
Hepatitis C virus (HCV) has been estimated to infect approximately 2–3% of the world’s population, with highest prevalence rates occurring in low and middle income regions including Africa and Southeast Asia [1,2,3,4]. Iatrogenic routes of transmission implicated in HCV infection include blood transfusions, surgical and dental procedures, dialysis, acupuncture, needlestick injury and use of unsterilised needles [4,9,10,11,12,13,14,15,16,17]. The latter has been highlighted in Egypt where nationwide treatment for schistosomiasis under suboptimal hygiene conditions from 1960 to 1987 has resulted in national HCV seroprevalence rates of approximately 14% [12,18]. Transmission is more commonly associated with haemodialysis compared to peritoneal dialysis and has been shown to be increased following longer durations of dialysis and increased frequency of blood transfusion [10,11,17]
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