Mixed Genotypes in Hepatitis C Virus Infection

Before the existence of commercial clotting factor concentrates, bleeding was the number one cause of death in persons with hemophilia and the only alternative treatment was cryoprecipitate. During the 1970s human freeze-dried (lyophilized) FVIII and FIX became available. The life of individuals with hemophilia was revolutionized because patients were able to treat themselves conveniently at home, as soon as spontaneous bleeds occurred. The commercial blood-derived products had a tremendous positive impact on physical, psychological and social lives. Unfortunately, they also carried an increased risk of bloodborne viral infections, largely due to their preparation from pools of plasma collected from thousands of donors. Consequently, the use of clotting factor concentrates resulted in human immunodeficiency virus (HIV) and hepatitis C virus (HCV) epidemics in this population (Lee C, 1995, 2009; Eyster, 2008; Ragni et al., 2010). As reported in different cohorts around the world, many patients with hemophilia became infected with HIV between 1982 and 1985. In some hemophilic populations, subsequent testing of stored frozen plasma samples revealed that the first infections with HIV occurred in 1978-79, that the bulk of patients were infected in 1981-82, and that there were very few new infections by the end of 1984 (Eyster, 2008; Goedert et al., 1985). The HCV epidemic was a much longer one, occurring between 1961 and 1985. The first patients became infected from the first large pool plasma-derived FIX concentrates and the epidemic ended with the dry heating of concentrates in 1985 (Lee C, 2009). Particularly in Argentina, commercial factor concentrates were not accessible until 1975. As a result of the economic situation of the country, the non-availability of more expensive products leaded to a lower rate of HIV-infected people that reached 17% of our hemophilic population. Heat-inactivated factor concentrates were not available until November 1985. Virtually, all hemophiliacs who received clotting factor concentrates prior to implementation of viral inactivation techniques became infected with hepatitis C virus at the time of the first infusion (Morfini et al, 1994; Lee C et al, 2002; Ragni et al, 2010). Prevalence rates of HCV infection up to 100% were reported in hemophilia patients treated with concentrates before 1985 (Yee et al., 2000; Lee C, 2009; Manucci, 2008; Arnold et al., 2006). Even though the introduction of heat-treated factor concentrates progressively decreased HCV transmission, the true risk ended when new regulations in blood donor screening together with the implementation of second and third generation immunoassays for the detection of antibodies against HCV was introduced in 1991 in Europe, in 1992 in the US and 1993 in