Hepatitis C

Hepatitis C is a form of hepatitis caused by the hepatitis C virus, which is transmitted through sexual contact or contact with infected blood or body fluids.

Hepatitis C

Incidence

In 2018, a total of 3,621 cases of acute hepatitis C were reported to CDC in the United States. After adjusting for under-ascertainment and under-reporting, an estimated 50,300 acute hepatitis C cases occurred in 2018. An estimated 2.4 million people in the United States were living with hepatitis C during 2013–2016.

Risk factors

• People with HIV infection
• Children born to mothers with HCV infection

Chronic hepatitis

• More than half of people who become infected with HCV will develop chronic infection.
• Of every 100 people infected with HCV, approximately 5–25 will develop cirrhosis within 10–20 years.
• Patients who develop cirrhosis have a 1%–4% annual risk of developing hepatocellular carcinoma and a 3%–6% annual risk of hepatic decompensation; for the latter patients, the risk of death in the following year is 15%–20%.

Who is more likely to develop cirrhosis after becoming infected with HCV? Rates of progression to cirrhosis are increased in the presence of a variety of factors, including

Methods by which Hepatitis C spreads

• Being male
• Being age >50 years
• Consuming alcohol
• Having nonalcoholic fatty liver disease, hepatitis B, or HIV coinfection
• Receiving immunosuppressive therapy (6,7,8)
• How many different genotypes of HCV exist?
• Seven HCV genotypes and 67 subtypes have been identified.

Genotypes

Genotypes 1a, 1b, 2, and 3 are the most common HCV genotypes in the United States.

Superinfection

Superinfection is possible if risk behaviors for HCV infection (e.g., injection-drug use) continue; however, superinfection does not appear to complicate decisions regarding treatment, because HCV antivirals with pan-genotypic activity are available.

Transmission

HCV is transmitted primarily through parenteral exposures to infectious blood or body fluids that contain blood. Possible exposures include

Hep C infection sources

• Injection-drug use (currently the most common mode of HCV transmission in the United States) (2)
• Birth to an HCV-infected mother

Although less frequent, HCV can also be spread through:

• Sex with an HCV-infected person (an inefficient means of transmission, although HIV-infected men who have sex with men [MSM] have increased risk of sexual transmission)
• Sharing personal items contaminated with infectious blood, such as razors or toothbrushes
• Other health-care procedures that involve invasive procedures, such as injections (usually recognized in the context of outbreaks)
• Unregulated tattooing
• Receipt of donated blood, blood products, and organs (rare in the United States since blood screening became available in 1992)
• Needlestick injuries in health-care settings

Blood transfusion and risk of HCV

Now that more advanced screening tests for hepatitis C are used in blood banks, the risk of transmission to recipients of blood or blood products is considered extremely rare, at <1 case per 2 million units transfused. Before 1992 (the year that blood screening became available), blood transfusion was a leading cause of hepatitis C virus transmission.

Medical and dental procedures

As long as Standard Precautions and other infection-control practices are consistently implemented, medical and dental procedures performed in the United States generally do not pose a risk for the spread of hepatitis C.

Signs and symptoms

People with newly acquired HCV infection usually are asymptomatic or have mild symptoms that are unlikely to prompt a visit to a health-care professional. When symptoms do occur, they can include:

HCV prevalence in USA

• Fever
• Fatigue
• Dark urine
• Clay-colored stool
• Abdominal pain
• Loss of appetite
• Nausea
• Vomiting
• Joint pain
• Jaundice

Incubation period

In those people who do develop symptoms, the average period from exposure to symptom onset is 2–12 weeks (range: 2–26 weeks) (13, 14).

Signs of chronic HCV

Most people with chronic HCV infection are asymptomatic or have non-specific symptoms such as chronic fatigue and depression. Many eventually develop chronic liver disease, which can range from mild to severe, including cirrhosis and liver cancer. Chronic liver disease in HCV-infected people is usually insidious, progressing slowly without any signs or symptoms for several decades. In fact, HCV infection is often not recognized until asymptomatic people are identified as HCV-positive when screened for blood donation or when elevated alanine aminotransferase (ALT, a liver enzyme) levels are detected during routine examinations.

Some people with chronic HCV infection develop medical conditions due to hepatitis C that are not limited to the liver. Such conditions can include:

• Diabetes mellitus
• Glomerulonephritis
• Essential mixed cryoglobulinemia
• Porphyria cutanea tarda
• Non-Hodgkin’s lymphoma

HCV virus and replicon organization and membrane organization of the viral proteins.

Testing and Diagnosis

CDC now recommends universal hepatitis C screening for all U.S. adults and all pregnant women during every pregnancy, except in settings where the prevalence of HCV infection is <0.1% (see How should providers determine hepatitis C prevalence?). This includes

• All adults aged 18 years and older
• All pregnant women during each pregnancy
• People who ever injected drugs and shared needles, syringes, or other drug preparation equipment, including those who injected once or a few times many years ago
• People with HIV
• People who have ever received maintenance hemodialysis
• People with persistently abnormal ALT levels
• People who received clotting factor concentrates produced before 1987
• People who received a transfusion of blood or blood components before July 1992
• People who received an organ transplant before July 1992
• People who were notified that they received blood from a donor who later tested positive for HCV infection
• Healthcare, emergency medical, and public safety personnel after needle sticks, sharps, or mucosal exposures to HCV‑positive blood
• Children born to mothers with HCV infection
• Any person who requests hepatitis C testing

Testing for HCV

Routine periodic testing is recommended for people with ongoing risk factors, while risk factors persist, including those who currently inject drugs and share needles, syringes, or other drug preparation equipment, along with people who have certain medical conditions (e.g., people who ever received maintenance hemodialysis). Testing of people at risk should occur regardless of setting prevalence.

Hepatitis C Virus Life Cycle

Several blood tests can detect HCV infection, including:

• Screening tests for antibody to HCV (anti-HCV)
• enzyme immunoassay (EIA)
• enhanced chemiluminescence immunoassay (CLIA)
• Chemiluminescence microparticle immunoassay (CMIA)
• Microparticle immunoassay (MEIA)
• Electrochemiluminescence immunoassay (ECLIA)
• Immunochromatographic assay (rapid test)
• Qualitative nucleic acid tests to detect presence HCV RNA
• Quantitative nucleic acid tests to detect levels of HCV RNA

Antibodies

Anti-HCV seroconversion occurs an average of 8–11 weeks after exposure, although cases of delayed seroconversion have been documented in people who are immunosuppressed (e.g., those with HIV infection).

Management and Treatment

• medical evaluation (by either a primary-care clinician or specialist [e.g., in hepatology, gastroenterology, or infectious disease]) for chronic liver disease, including treatment and monitoring;
• hepatitis A and hepatitis B vaccination;
• screening and brief intervention for alcohol consumption; and
• HIV risk assessment and testing.

Treatment guidelines and genotypes

There are several genotypes of HCV the type of which can determine treatment.

• Treatment-Naive Genotype 1
• Treatment-Naive Genotype 2
• Treatment-Naive Genotype 3
• Treatment-Naive Genotype 4
• Treatment-Naive Genotype 5 or 6

• HCV Guidelines

Hepatitis C Resources
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