Hepatitis C: risk factors

In Scotland, following the introduction of virus-killing heat treatment of blood factor in 1986 and universal screening of blood donors in 1991, persons have not been at risk of acquiring the hepatitis C virus (HCV) through receiving infected blood products.

In resource-rich countries such as Scotland, HCV is now mainly transmitted amongst people who inject drugs and share injecting equipment, contributing to an estimated 90% of infections in the UK according to the Hepatitis C Trust. The high rate of illegal drug use on entering prison in Scotland (estimated by the Scottish Prison Survey to be 71% in 2018/19) has also historically rendered prisoners a risk group, with a 2013 survey finding HCV prevalence in prisoners to be 19% compared to less than 1% in the general population (Taylor et al, 2013). However, this survey identified very few cases of in-prison transmission. More recent data on HCV prevalence in prisons and uptake of screening is limited, and the decline in general population prevalence in recent years may be reflected in prisons also.  Please see ScotPHO website sections on Drug Use and Health in Prison for further information.

In resource-poor countries, blood transfusions remain a major source of HCV infections. This is largely due poor healthcare practice such as either reuse of medical equipment or improper sterilisation methods, and poor infrastructure for safe blood transfusions, for example frequent electrical outages (Prati, 2006). The age profile of blood transfusion recipients also varies between resource-rich and -poor countries: while elderly patients make up the majority of transfusions in resource-rich countries, in resource-poor countries young women and children more commonly receive transfusions, for example due to complications in childbirth or as malaria treatment in children. Younger age at infection means infected individuals contribute to prevalence for a longer period of time (Prati, 2006).

Less commonly, HCV can be transmitted either from mother to infant or sexually, particularly in HIV-infected individuals and men who have sex with men (Manns et al, 2017).