Widespread Hepatitis C Virus Transmission Network Among People Who Inject Drugs in Kenya
Hepatitis C virus (HCV) disproportionately affects people who inject drugs (PWID) worldwide. Despite carrying a high HCV burden, little is known about transmission dynamics in low- and middle-income countries.
Researchers recruited PWID from Nairobi and coastal cities and towns of Mombasa, Kilifi, and Malindi in Kenya at needle and syringe programs. Next-generation sequencing data from HCV hypervariable region 1 were analyzed using Global Hepatitis Outbreak and Surveillance Technology to identify transmission clusters.
HCV strains belonged to genotype 1a (n = 64, 46.0%), 4a (n = 72, 51.8%) and mixed HCV/1a/4a (n = 3, 2.2%). HCV/1a was dominant (61.2%) in Nairobi, whereas HCV/4a was dominant in Malindi (85.7%) and Kilifi (60.9%), and both genotypes were evenly identified in Mombasa (45.3% for HCV/1a and 50.9% for HCV/4a). Global Hepatitis Outbreak and Surveillance Technology identified 11 transmission clusters involving 90 cases. Strains in the two largest clusters (n = 38 predominantly HCV/4a and n = 32 HCV/1a) were sampled from all four sites.
Transmission clusters involving 64.7% of cases indicate an effective sampling of major HCV strains circulating among PWID. Large clusters involving 77.8% of clustered strains from Nairobi and Coast suggest successful introduction of two ancestral HCV/1a and HCV/4a strains to PWID and the existence of a widespread transmission network in the country. The disruption of this network is essential for HCV elimination.
Full study results, published in International Journal of Infectious Diseases, can be accessed here.
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Another study, published in the Journal of Epidemiology and Global Health, showed that there is a higher prevalence of HCV in key populations such as HIV-infected individuals and drug users than in the general population in Kenya. It found that HCV genotypes 1 and 4 were the most common genotypes, but more data from the general population is required in order to establish baseline data on the prevalence and genotypes of HCV in Kenya.