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Public Health - Seattle & King County

Hepatitis C

Hepatitis C virus (HCV) infects the liver and is transmitted primarily by direct exposure to the blood of an infected person. Before HCV screening of blood and blood-products was introduced in 1992, transfusions accounted for a large proportion of infections. Today, most infections are associated with injection drug use (IDU). HCV can also be spread during childbirth and through sexual exposure, but both routes of transmission are uncommon. Approximately 5% of HCV positive women transmit the virus to their infant. HCV does not spread readily through sexual activity and is more likely to occur by this route in men who have sex with men. Approximately 75-95% of newly infected persons are asymptomatic. As a result, most people with chronic infection are unaware that they have HCV. Although treatment for chronic hepatitis C infections is available, no post-exposure prophylaxis regimen is available to prevent infection. There are an estimated 3.2 million chronically infected persons in the United States. The prevalence of chronic hepatitis C infection is the highest among persons born in 1945-1965. Seventy-five to 85% of people who get hepatitis C will become chronic carriers (chronic infection). Sixty to 70% of people with chronic infection will develop chronic liver disease. About 20% of persons with chronic hepatitis C will develop serious liver problems including cirrhosis and liver cancer 20 to 30 years after becoming infected.

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Hepatitis C in King County

Purpose of surveillance:

  • To identify risk factors for infection
  • To identify and eliminate sources of transmission
  • To provide education to cases in order to minimize risk of transmission and to reduce risk factors for development of chronic liver disease
  • To monitor the prevalence of disease and associated disease burden in the community
  • To identify epidemiological features of hepatitis C to guide prevention activities and HCV-related services

Hepatitis C - Acute

Hepatitis C - Chronic

Local epidemiology:

In 2014, 1258 chronic HCV cases (current or past HCV infection) and 20 acute HCV cases were reported. Of the chronic cases, 1232 were categorized as confirmed and 26 as probable. An additional 116 HCV case reports were received that did not include enough information to categorize. Between six and 20 reports of acute HCV infection are received annually, compared to 1,000–2,000 reports of chronic HCV infection.

Each year in Washington state fewer than 30 acute infections and between 5,000 and 6,000 cases of chronic HCV are reported.