Epidemiology and Genotype Distribution of Hepatitis C Virus In Russia

Hepatitis C virus (HCV) causes both acute and chronic disease of the liver that can lead to liver cirrhosis, cancer and liver failure. HCV is characterized by high genetic diversity and substantial variations in prevalence of specific HCV genotypes in different countries of the world. Many effective regimens of direct-acting antivirals (DAAs), including pan-genotypic, can successfully treat HCV infection. However, genotype-specific treatments for HCV are being actively employed in the national plans for elimination of HCV infection around the world. Evaluation of HCV genotype prevalence in a country is mandatory for successful implementation of the national plans for elimination of HCV infection and allocation of financial resources to DAAs most effecting for specific HCV genotypes prevalent in a country. Here, we analyzed HCV genotypes, subgenotypes and recombinants in 10,107 serum samples from patients with chronic HCV infection from all Federal districts of Russia collected in 2015-2017. This is the first, largest evaluation of HCV genotypes performed on samples from all territories of Russia, from its Central Federal district to the Far East. Moreover, we have updated retrospective epidemiological analysis of chronic and acute HCV infection in Russia in 2001-2021. We demonstrate that the incidence of acute HCV infection in Russia reduced from 16.7 cases per 100,000 population in 2001 to 0.6 cases per 100,000 population in 2021. The number of cases of chronic HCV infection decreased from 29.5 to 16.4 per 100,000 population during this period. HCV genotype analysis indicated that HCV genotype 1 dominates in Russia (53.6%). Genotypes 3 and 2 were detected in 35.4% and 7.8% of patients respectively. These proportions are virtually identical in all regions of Russia except for Far East, where HCV genotype 2 amounts only to 1%. HCV genotypes 1 and 2 are more widespread in women, while HCV genotype 3 in men. The highest frequency of identification of genotype 3 was found in the age group of 31-40 years old (44.9%, respectively), and genotype 1 was more prevalent in a group of over 70 years old (72.2%). The proportion of HCV genotype 2 is predominant among HCV-infected persons older than 40 years. Discriminating HCV genotype 2 and recombinant RF1_2k/1b, which are frequently misclassified, is important for successful antiviral treatment of such patients. For the first time, we demonstrate the countrywide prevalence of HCV RF1_2k/1b in different regions of Russia. HCV RF1_2k/1b amounts to 3.2% in the structure of HCV genotypes, reaching 30% among samples classified as genotype 2 by some commercial genotyping tests. The highest proportion of HCV RF1_2k/1b was detected in the north-west (60%), southern (41.6%) and central (31.6%) federal district. Its frequency in Far Eastern and North Caucasus Districts was ~ 14.3%. HCV RF1_2k/1b was not detected in the Volga, Ural and Siberian districts. To conclude, this is the first and most complete evaluation of HCV epidemiology and genotype/subgenotype distribution in Russia.