Epidemiology for Hepatitis C

Worldwide, it is estimated that 130-170 million people are living with chronic hepatitis C infection (~3% of the world's population), that it infects 3-4 million people per year, >10% of these people will develop liver cirrhosis or cancer over time and that more than 350,000 people die from hepatitis C related diseases each year. Countries with particularly high rates of infection include Egypt (22%), Pakistan (4.8%) and China (3.2%). There are about 35,000 to 185,000 new cases a year in the United States. It is currently a leading cause of cirrhosis, a common cause of hepatocellular carcinoma, and as a result of these conditions it is the leading reason for liver transplantation in the United States. Coinfection with HIV is common, and rates among HIV positive populations are higher. Annual deaths from HCV in the United States range from 10,000 to 20,000; expectations are that this mortality rate will increase, as those who were infected by transfusion before HCV testing become apparent. A survey conducted in California showed a prevalence of up to 34% among prison inmates; 82% of subjects diagnosed with hepatitis C have previously been in jail, and transmission while in prison is well described.

Prevalence is higher in some countries in Africa and Asia. Egypt has the highest seroprevalence for HCV, up to 20% in some areas. There is a hypothesis that the high prevalence is linked to a now-discontinued mass-treatment campaign for schistosomiasis, which is endemic in that country. Regardless of how the epidemic started, a high rate of HCV transmission continues in Egypt, both iatrogenically and within the community and household.

Coinfection with HIV
Approximately 350,000 people (35% of patients) in the USA infected with HIV are coinfected with the hepatitis C virus, mainly because both viruses are blood-borne and are present in similar populations. HCV is the leading cause of chronic liver disease in the USA. It has been demonstrated in clinical studies that HIV infection causes a more rapid progression of chronic hepatitis C to cirrhosis and liver failure. This is not to say treatment is not an option for those living with coinfection.

In a study involving 21 HIV coinfected patients (DICO), pretreatment baseline plasma levels of IP-10 predicted the reduction of HCV RNA during the first days of interferon/ribavirin therapy (“first phase decline”) for HCV genotypes 1-3, as is also the case in HCV monoinfected patients. Pretreatment IP-10 levels below 150 pg/mL are predictive of a favorable response, and may thus be useful in encouraging these otherwise difficult-to-treat patients to initiate therapy.