Hepatitis C

Epidemiology of Infectious Diseases: Hepatitis C

Causal agent
Hepatitis C virus. There are 6 HCV genotypes and > 100 subtypes.

Common clinical features
Up to 90% of acute infections are asymptomatic.
Symptoms may include, fatigue, abdominal pain, anorexia, nausea, vomiting and jaundice (rare).

Up to 20% of individuals infected with HCV will clear the virus in 2-6 months.  Of those chronically infected 75% will have some degree of active liver disease and of these 25% will progress to cirrhosis over the ensuing 20 years of whom 1-4%will develop liver cancer each year2.

Epidemiology

  • Endemic worldwide.
  • HCV is a major cause of liver disease worldwide.
  • The World Health Organisation estimate that 180 million people are infected with HCV worldwide, 130 million of whom are chronic HCV carriers at risk of developing liver cirrhosis and/or cancer.
  • In England and Wales there were 8,240 laboratory confirmed cases of HCV in 2004.
  • In England the prevalence of HCV is estimated to be 0.5% (approximately 200,000 individuals are chronically infected).  Amongst diagnosed infections, injecting drug use is the single biggest risk factor, accounting for more than 90% of infections3, 4.
  • An estimated 5 out of 6 people in the UK with chronic hepatitis C infection are unaware of their infection4.
  • Most people diagnosed with hepatitis C infection are men aged between 25 and 45 years, reflecting the fact that men are more likely to be injecting drug users3.
  • The prevalence of hepatitis C in injecting drug users in contact with health services is estimated at 38%3.

Reservoir
Humans

Mode of transmission

  • Contact with infected blood or bodily fluids. The primary mode of transmission is through contaminated blood 2, 3.
  • Other less efficient modes of transmission include; mother to child transmission (vertical transmission), sexual transmission, exposure to contaminated medical and dental procedures abroad, tattooing or skin piercing with blood contaminated equipment and patient to health care worker and vice versa2.
  • The highest risk groups are current and past injecting drug users, those who received blood products before 1986 and recipients of blood transfusions before 1991.

Incubation period
Range 2-6 weeks, commonly 6-9 weeks.

Period of Communicability
From 1 week or more before onset of first symptoms. May persist indefinitely1.

Laboratory Confirmation
Anti-HCV IgG antibody tests are normally positive within 3 months of infection2.

Prevention and control
No vaccine is available for HCV.

In 2004 the National Institute for Clinical Excellence (NICE) recommended a combination therapy with peginterferon alfa and ribavirin for people aged 18 years and over with moderate to severe chronic hepatitis C5.

References

  1. Heymann D L, editor, Control of Communicable Disease Manual. 18th ed. American Public Health Association; 2004.
     
  2. Hawker J, Begg N, Blair I, Reintjes R, Weinberg J. Communicable Disease Control Handbook, Blackwell, 2005.
     
  3. Department of Health. Hepatitis C Action Plan for England, Department of Health 2004. Available at: http://www.dh.gov.uk/assetRoot/04/08/47/13/04084713.pdf
     
  4. Health Protection Agency. Hepatitis C in England: The First Health Protection Agency Annual Report 2005. London: Health Protection Agency Centre for Infections. December 2005. Available at: http://www.hpa.org.uk/publications/2005/hepC/hepC_ann_rpt.pdf
     
  5. National Institute for Clinical Excellence. Interferon alfa (pegylated and non-pegylated) and ribavirin for the treatment of chronic hepatitis C. Technology Appraisal 75. London: clinical Institute for Clinical Excellence; January 2004. Available at http://www.nice.org.uk/page.aspx?o=ta075quickrefguide 

Further Resources

Health Protection Agency. Standards for Local Surveillance and Follow Up of Hepatitis B and C 2006, HPA. Available at: http://www.hpa.org.uk/infections

Department of Health. Hepatitis C: Essential information for professionals and guidance on testing, Department of Health July 2004. Available at: http://www.dh.gov.uk/assetRoot/04/09/79/56/04097956.pdf

Department of Health - Key Hepatitis C documents for health practitioners available at; http://www.dh.gov.uk/PolicyAndGuidance/HealthAndSocialCareTopics

© CM Kirwan 2006