Hepatitis C is a liver disease caused by the hepatitis C virus (HCV). HCV infection sometimes results in an acute illness,
but most often becomes a chronic condition that can lead to cirrhosis of the liver and liver cancer.
Transmission: Contact with the blood of an infected person, primarily through sharing contaminated needles to inject
drugs.
Vaccination: There is no vaccine for hepatitis C.
Hepatitis C virus (HCV) infection is the most common chronic bloodborne infection in the United States; approximately
3.2 million persons are chronically infected. Although HCV is not efficiently transmitted sexually, persons at risk for
infection through injection drug use might seek care in STD treatment facilities, HIV counseling and testing facilities,
correctional facilities, drug treatment facilities, and other public health settings where STD and HIV prevention and
control services are available.
Sixty to 70% of persons newly infected with HCV typically are usually asymptomatic or have a mild clinical illness. HCV
RNA can be detected in blood within 1–3 weeks after exposure. The average time from exposure to antibody to HCV
(anti-HCV) seroconversion is 8–9 weeks, and anti-HCV can be detected in >97% of persons by 6 months after
exposure. Chronic HCV infection develops in 70%–85% of HCV-infected persons; 60%–70% of chronically infected
persons have evidence of active liver disease. The majority of infected persons might not be aware of their infection
because they are not clinically ill. However, infected persons serve as a source of transmission to others and are at risk
for chronic liver disease or other HCV-related chronic diseases decades after infection.
HCV is most efficiently transmitted through large or repeated percutaneous exposure to infected blood (e.g., through
transfusion of blood from unscreened donors or through use of injecting drugs). Although much less frequent,
occupational, perinatal, and sexual exposures also can result in transmission of HCV.
The role of sexual activity in the transmission of HCV has been controversial. Case-control studies have reported an
association between acquiring HCV infection and exposure to a sex contact with HCV infection or exposure to multiple
sex partners. Surveillance data also indicate that 15%–20% of persons reported with acute HCV infection have a history
of sexual exposure in the absence of other risk factors. Case reports of acute HCV infection among HIV-positive MSM
who deny injecting-drug use have indicated that this occurrence is frequently associated with other STDs (e.g.,
syphilis). In contrast, a low prevalence (1.5% on average) of HCV infection has been demonstrated in studies of long-
term spouses of patients with chronic HCV infection who had no other risk factors for infection. Multiple published
studies have demonstrated that the prevalence of HCV infection among MSM who have not reported a history of
injecting-drug use is no higher than that of heterosexuals. Because sexual transmission of other bloodborne viruses,
such as HIV, is more efficient among homosexual men than in heterosexual men and women, the reason that HCV
infection rates are not substantially higher among MSM is unclear. Overall, these findings indicate that sexual
transmission of HCV is possible but inefficient.
http://www.cdc.gov/hepatitis/HCV.htm