Injecting Drug Use: A Vector for the Introduction of New Hepatitis C Virus Genotypes

Hepatitis C virus (HCV) genotypes’ monitoring allows real-time insight into the dynamic changes that occur in the global epidemiological picture of HCV infection. Intravenous drug use is currently the primary driver for HCV transmission in developed and developing countries. The distribution of HCV genotypes/subtypes differs significantly between people who inject drugs (PWID) and the general population. HCV genotypes that previously exhibited a limited geographical distribution (3a, 4) are becoming more prevalent in this high-risk group. Immigration from HCV-endemic countries and the evolving networks of HCV transmission in PWID influence HCV genotypes distribution in Europe. Social vulnerabilities (e.g., unemployment, homelessness, and limited access to social and healthcare insurances systems) are important triggers for illicit drug use, which increases the associated risks of HCV infection and the frequent emergence of less prevalent genotypes. Genotype/subtype determination bears important clinical consequences in the progression of liver disease, susceptibility to antiviral therapies and the emergence of resistance-associated variants. An estimated half of the chronically HCV-infected PWID are unaware of their infection, and only one in ten of those diagnosed enter treatment. Nevertheless, PWID exhibit high response rates to new antiviral regimens, and the level of HCV reinfection is unexpectedly low. The focus of the healthcare system must be on the early detection and treatment of infection, to avoid late presentations that are associated with high levels of viremia and liver fibrosis, which may diminish the therapeutic success rate.

Below:  Correlation between the gross national income and the hepatitis index in the top 10 most populated European countries. The gross national income per capita (GNI) directly correlates with the public health performances in the handling and treatment of hepatitis C virus infections (evaluated using the hepatitis index), as calculated by the Euro Hepatitis Report (2012) elaborated by Health Consumer Powerhouse[83].

Table 1

The burden of hepatitis C virus infection in the WHO regions and the proportion of people who inject drugs

WHO regions	Population (millions)1	Estimated HCV seroprevalence2 (%)	Estimated prevalence of viremic persons3 (%)	Proportion of PWID lowest-highest estimates4
Africa	1396	1.0-5.3	0.6-4.1	55-97
Latin America	572	0.9-1.3	0.6-1.0	69-96
North America	355	1.3	0.8-1.0
Europe	751	0.9-3.3	0.6-2.3	36-69
Asia	3985	1.1-5.4	0.7-2.3	50-53

Data sources:

1World health statistics, 2014 (available from: www.who.int/world_health_statistics);

2Mohd Hanafiah K, 2013[3];

3Gower E, 2014[10] and Global Health Observatory Data Repository (http://apps.who.int/gho/data);

4World Drug report 2014[12]. PWID: Proportion of people who inject drugs; HCV: Hepatitis C virus.

Table 2

Hepatitis C virus infection prevalence in the general population and in people who inject drugs in the most populated European countries

Country	Population (millions)1	Injecting drug use (rate/1000 inhabitants)2	HCV prevalence in the general population3	HCV prevalence in PWID4
Germany	80.4	4.25-5.04	0.7	51
France	65.6	6.7-8.8	0.85	73
United Kingdom	63.7	3.3	0.6	47.9
Italy	59.5	10	3.0	61.0-64.8
Spain	41.0	0.2	1.5	73.3-85.9
Poland	38.5	2.9	1.5	44.3 72.4
Romania	20.0	NA	2.1-2.4	82.4
Netherlands	16.7	0.2	0.2	50-86
Greece	10.9	1.1	> 1.5	60-73
Sweden	9.5	4.9	0.5	83

Data sources:

1World health statistics 2014 (available from: www.who.int/world_health_statistics; 2,4ECMDDA, 2013[33];

3Mühlberger N, 2009[30] and Cornberg M, 2011[16]. NA: Not available. PWID: People who inject drugs; HCV: Hepatitis C virus.

Full article at: http://goo.gl/pLXN27

By: Simona Ruta and Costin Cernescu

Stefan S. Nicolau Institute of Virology, 030304 Bucharest, Romania

  

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