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Hepatitis A (General Information)
Last updated 5/13/2010
Hepatitis A is a liver disease that is caused by the hepatitis A virus. Symptoms can include fever, jaundice (yellow skin and/or eyes), stomach pains, diarrhea, joint pain, and rash. The hepatitis A virus is found in the stool of infected persons and can be spread by close personal contact, especially to those within a household, and sometimes by contaminated food or water.
Hepatitis A infection can be prevented through vaccination with hepatitis A vaccine which is now part of the routine childhood immunization schedule. The vaccine is also recommended for persons at increased risk for hepatitis A (e.g., travelers to endemic areas, close contacts of newly arriving international adoptees, users of illicit drugs, or men who have sex with men).
Reference: CDC Update - Prevention of Hepatitis A after Exposure to Hepatitis A Virus and in International Travelers.Updated Recommendations of the Advisory Committee on Immunization Practices (ACIP). (MMWR 10/19/07 2007;56(51):1080-4, Vol. 56, No. 41) available at www.cdc.gov/mmwr/preview/mmwrhtml/mm5641a3.htm.
When administered within 2 weeks of exposure, immune globulin (IG) is 80%-90% effective in preventing clinical hepatitis A and hepatitis A vaccine has comparable efficacy. Persons who have been administered at least one dose of hepatitis A vaccine at least 1 month before exposure to hepatitis A virus (HAV) do not need postexposure prophylaxis.
Persons who have been recently exposed (see exposure groups below) to hepatitis A virus, who have not previously been administered hepatitis A vaccine, and do not have a previous history of laboratory-confirmed hepatitis A should be administered a single dose of single-antigen hepatitis A vaccine or immune globulin (IG, 0.02 mL/kg) as soon as possible, but not >2 weeks after the most recent exposure.
For children < 12 months of age, IG should be used
For healthy persons aged 12 months-40 years, single-antigen hepatitis A vaccine at the age-appropriate dose is preferred
For healthy persons aged 41-59 years, vaccine and/or IG can be used1
For persons ≥ 60 years, IG is preferred; vaccine can be used if IG cannot be obtained
For persons of any age with immunocompromise, who have chronic liver disease, and/or for whom vaccine is contraindicated, IG should be used
1Note: For persons >40 years, CDC prefers IG (although vaccine can be used if IG is not available) because of limited immunogenicity data for older people in the setting of an outbreak. However, other countries recommend vaccine as post exposure prophylaxis in older people and there is evidence that vaccine is immunogenic in people <70 years of age. Therefore, the California Department of Public Health (CDPH) suggests consideration of vaccine in persons >40 years of age because it confers long-term immunity. (See CDPH Hepatitis A Public Health Investigation Quicksheet, March 2008, at www.cdph.ca.gov/programs/immunize/Documents/CDPH_HAV%20quicksheet_March08.pdf)
Because hepatitis A cannot be reliably diagnosed on clinical presentation alone, serologic confirmation of HAV infection in index patients by IgM anti-HAV testing is recommended before postexposure prophylaxis of contacts. Screening of contacts for immunity before giving postexposure prophylaxis is not recommended because screening is more costly and would delay its administration. If hepatitis A vaccine is recommended for a person being given IG, it may be administered simultaneously with IG at a separate anatomic injection site. For persons who receive hepatitis A vaccine, the second dose should be administered according to the licensed schedule of the product.
Postexposure prophylaxis (PEP) should be administered to previously unvaccinated persons in the following situations:
Close personal contact: Postexposure prophylaxis should be administered to all unvaccinated household and sexual contacts of persons who have hepatitis serologically confirmed (hepatitis IgM anti-HAV positive) as hepatitis A. PEP should also be administered to unvaccinated persons who have shared illicit drugs with a person with serologically confirmed acute hepatitis A, and should be considered for unvaccinated persons with ongoing close personal contact (e.g., regular babysitting) with a person with hepatitis due hepatitis A virus infection.
Day care centers: In day care centers or homes where children who wear diapers are cared for, PEP should be administered to all previously unvaccinated staff and attendees if a) one or more cases of hepatitis A are recognized in children or employees or b) cases are recognized in two or more households of center attendees. In centers that do not provide care to children who wear diapers, PEP need be given only to unvaccinated classroom contacts of an index case-patient. When an outbreak occurs (i.e., hepatitis cases in three or more families), PEP also should be considered for unvaccinated members of households that have children (center attendees) in diapers.
Common-source exposure: If a food handler is diagnosed with hepatitis A, PEP should be administered to other food handlers at the same location. Because common-source transmission to patrons is unlikely, PEP for patrons is usually not recommended but may be considered if a) during the time when the food handler was likely to be infectious, the food handler both directly handled uncooked foods or foods after cooking and had diarrhea or poor hygienic practices and b) patrons can be identified and treated within 2 weeks after the exposure. In settings where repeated exposures to HAV may have occurred (e.g., institutional cafeterias), stronger consideration of PEP for patrons may be warranted. In the event of a common-source outbreak, PEP should not be administered to exposed persons after cases have begun to occur because the 2-week period during which PEP is known to be effective will have been exceeded.
Schools, hospitals, and work settings: PEP is not routinely indicated when a single case occurs in an elementary or secondary school, an office, or in other work settings, and the source of infection is outside the school or work setting. Similarly, when a person who has hepatitis A is admitted to a hospital, staff should not routinely be administered PEP; instead, careful hygienic practices should be emphasized. PEP should be administered to persons who have close contact with index patients if an epidemiologic investigation indicates HAV transmission has occurred among students in a school or among patients or between patients and staff in a hospital.
Note: All confirmed or suspect acute hepatitis A cases, including all positive laboratory tests for IgM anti-HAV antibody, should be reported to Epidemiology & Assessment (phone 714-834-8180 or fax 714-834-8196) within one working day of identification.
Once a case of confirmed or suspect acute hepatitis A has been reported, Epidemiology will make recommendations for postexposure prophylaxis as needed for close contacts, day care situations, common-source exposures, schools, hospitals and work settings. Epidemiology will provide and administer PEP to those for whom we have recommended it if not available in a timely manner through the usual source of health care.
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