Hepatitis B Quiz

Hepatitis B Virus Epidemiology, Clinical Features, and Laboratory Diagnosis

• HBV is transmitted through percutaneous or mucosal exposure to infectious blood or body fluids.
• HBV can remain viable on environmental surfaces for 7 days or longer.
• Sexual contact and percutaneous exposure to blood are the two primary sources of HBV infection in adults.
• The risk of HBV infection after a needlestick injury is 37-62% if the source patient is HBeAg positive and 23-37% if the patient is HBeAg negative.
• HBV infection can produce either asymptomatic or symptomatic infection, with an average incubation period of 90 days.
• Jaundice, dark urine, and scleral icterus are usually present in symptomatic patients.
• Extreme elevations in serum aminotransferase levels are the most striking laboratory findings in HBV infection.
• The fatality rate among persons with reported cases of acute hepatitis B is 0.5-1.0%, with the highest rates in adults older than 60 years.
• <5% of adults with acute HBV infection progress to chronic HBV infection and are at risk for chronic hepatitis, cirrhosis, and primary hepatocellular carcinoma.
• Serologic assays are used to differentiate HBV from other causes of hepatitis.
• Several well-defined antigen-antibody systems are associated with HBV infection, including HBsAg, anti-HBs, HBcAg, anti-HBc, HBeAg, and anti-HBe.
• The persistence of HBsAg for 6 months after the diagnosis of acute HBV is indicative of progression to chronic HBV infection.

Preventing and Managing Hepatitis B Infection

• Hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (HAnti-HBc) are used to detect acute or chronic HBV infection.
• IgM and IgG antibodies can be detected with the total anti-HBc assay.
• Transient HBsAg positivity may occur during vaccination.
• HBeAg is associated with high infectivity, while anti-HBe indicates lower levels of virus.
• All HBsAg-positive persons are potentially infectious, regardless of their HBeAg or anti-HBe status.
• Qualitative or quantitative tests for HBV DNA are used for patients on antiviral therapy.
• Supportive care is the only treatment for acute hepatitis B, while chronic HBV infection requires medical evaluation and regular monitoring.
• Seven drugs are approved for treatment of chronic hepatitis B, including interferon alfa and lamivudine.
• Hepatitis B vaccine is the most effective measure to prevent HBV infection and its consequences.
• Three doses of hepatitis B vaccine induce a protective antibody response in more than 90% of healthy recipients.
• Booster doses of hepatitis B vaccine are not necessary, and periodic serologic testing is not recommended.
• Implementation of Standard Precautions in healthcare settings, use of sharps with safety features, increasing levels of hepatitis B vaccination coverage among HCP, and use of PEP have contributed to reducing the risk for HBV infection among HCP.

Hepatitis B and C: Epidemiology, Testing, Treatment, and Prevention

• Hepatitis B virus (HBV) infection can be prevented through vaccination.
• Persons previously infected with HBV are immune to reinfection and do not require postexposure prophylaxis.
• Hepatitis C virus (HCV) infection is the most common chronic bloodborne infection in the United States, affecting an estimated 3.2 million persons.
• HCV transmission occurs primarily through exposure to infected blood, with injection drug use being the most commonly identified risk factor for transmission.
• HCP exposed to infected blood through needlestick injuries may acquire HCV infection.
• Laboratory testing is necessary to establish a specific diagnosis of hepatitis C, with serologic assays for antibodies to HCV and nucleic acid tests (NAT) to detect HCV RNA as the two major types of tests available.
• Antiviral therapy is recommended for persons with persistently elevated ALT levels, detectable HCV RNA, and a liver biopsy that indicates either portal or bridging fibrosis or moderate degrees of inflammation and necrosis.
• The combination of weekly subcutaneous injections of long-acting peginterferon alfa and oral ribavirin has resulted in virus elimination in 40% to 50% of treated persons infected with genotypes 1 or 4 and in 75% to 85% of those infected with genotypes 2 or 3.
• Successful treatment eliminates viremia and the potential for HCV transmission and further chronic liver disease.
• No vaccine against HCV infection exists.
• National recommendations for prevention and control of HCV infection emphasize primary prevention activities to reduce the risk for HCV transmission, including screening and testing of blood donors, viral inactivation of plasma-derived products, risk-reduction counseling and screening of persons at risk for HCV infection, and adherence to Standard Precautions and safe work practices in healthcare settings.
• Postexposure prophylaxis with immune globulin antiviral agents or immunomodulators is not recommended after exposure to HCV-positive blood.