Clinical review of the impacts of hepatitis C

4. Hepatitis C Virus: Facts and Figures

4.1 General

• The Hepatitis C Virus ( HCV) was discovered in 1989; hitherto, acute symptomatic hepatitis, particularly among blood and blood product recipients, which was not caused by Hepatitis A or B viruses, was referred to as non-A, non-B Hepatitis.
• A diagnostic test, the HCV antibody test, began being used in 1991.
• Worldwide, it is estimated that 80 million people are living with chronic Hepatitis C infection.
• Infected people were first treated with standard interferon in 1994 - with effectiveness (sustained viral response, i.e. sustained clearance of virus from the blood) rates of 10-20%.
• Pegylated Interferon and Ribavirin therapy became available in 2001 – with effectiveness rates of 50-60% overall (the rate was considerably lower among people infected through blood transfusion/blood products as their infections tended to be of the Genotype 1 variety - a strain which is less responsive to this type of treatment).
• During 2014-17 a range of all-oral, safe and highly effective therapeutic agents became available (the Direct Acting Antivirals ( DAAs)), for all genotypes of Hepatitis C; effectiveness rates of between 95 and 100% are achieved, even in individuals with compensated cirrhosis ( 4 ).

4.2 Epidemiology of Hepatitis C in Scotland

As at 2017 ( 5, 6 )

• Approximately 34,000 people were chronically infected with Hepatitis C; this figure excludes tens of thousands of people who were infected, but cleared their virus spontaneously or through treatment, or who have died.
• 45% of the 34,000 were undiagnosed.
• Of the undiagnosed, it is estimated that only a very small number (less than 30) are people who acquired their Hepatitis C through blood transfusion ( 7 ).
• Four hundred and forty four people were known to have acquired hepatitis C infection through blood transfusion or blood factor in Scotland and were beneficiaries of the SIBSS.
• It is estimated that between 500 and 1000 people became infected with Hepatitis C during 2017; almost all acquired their infection through injecting drug use behaviours.
• Since the implementation of heat treatment for blood factor in 1986 and the testing of blood donors for hepatitis C in 1991, there have been no acquisitions of infection through the receipt of blood factor or blood transfusion, respectively, in Scotland.

4.3 Impact of Hepatitis C on Severe Life-Threatening Illness and Life Expectancy Once an Individual has Developed Cirrhosis of the Liver

The life expectancy of someone who has developed cirrhosis of the liver is considerably reduced as indicated below (table 2).

• Among untreated or unsuccessfully treated individuals, the estimated rate of progression from compensated cirrhosis to decompensated cirrhosis (liver failure) is 6.5% per year ( 8 ).

• Among successfully treated individuals, the estimated rate of progression from compensated cirrhosis to decompensated cirrhosis is 0.5%. However, this estimate is based on one single study only ( 9 ).
• Among untreated or unsuccessfully treated individuals, the estimated rate of progression from compensated cirrhosis to hepatocellular carcinoma is 3.5% per year ( 9, 10 ).
• Among successfully treated individuals the estimated rate of progression from compensated cirrhosis to hepatocellular carcinoma is 1-1.3% per year ( 9, 10 ).
• Among untreated or unsuccessfully treated individuals, the estimated rate of progression from liver failure to death is 18.5% per year ( 8 ).
• Among successfully treated individuals, the estimated rate of progression from liver failure to death is unclear at present; successful treatment of patients with liver failure is a new phenomenon and, thus, more time needs to elapse in order to determine this progression rate.

Table 2: Impact of Hepatitis C on severe, life-threatening illness and life expectancy