Hepatitis A primary prevention
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Hepatitis A |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Varun Kumar, M.B.B.S. [2]
Overview
- Hepatitis A can be prevented by good hygiene and sanitation. Vaccination is also available, and is reconmended in areas where the prevalence of hepatitis A is high. To prevent it, use your own towels and toothbrushes, eating utensils, and other personal products. Always wash your hands after and before eating and more importantly after using the toilet.
- Two products are used to prevent hepatitis A virus infection: immune globulin and hepatitis A vaccine.
- Immune globulin is a preparation of antibodies that can be given before exposure for short-term protection against hepatitis A and for persons who have already been exposed to hepatitis A virus. Immune globulin must be given within 2 weeks after exposure to hepatitis A virus for maximum protection.
- Hepatitis A vaccine has been licensed in the United States for use in persons 12 months of age and older. The vaccine is recommended (before exposure to hepatitis A virus) for persons who are more likely to get hepatitis A virus infection or are more likely to get seriously ill if they do get hepatitis A. The vaccines currently licensed in the United States are HAVRIX® (manufactured by GlaxoSmithKline) and VAQTA® (manufactured by Merck & Co., Inc).
Hepatitis A Vaccine
Inactivated and attenuated hepatitis A vaccines have been developed and evaluated in human clinical trials and in nonhuman primate models of HAV infection; however, only vaccines made from inactivated HAV have been evaluated for efficacy in controlled clinical trials. The vaccines containing HAV antigen that are currently licensed in the United States are the single-antigen vaccines HAVRIX® (manufactured by GlaxoSmithKline, Rixensart, Belgium) and VAQTA® (manufactured by Merck & Co., Inc., Whitehouse Station, New Jersey) and the combination vaccine TWINRIX® (containing both HAV and HBV antigens; manufactured by GlaxoSmithKline). All are inactivated vaccines.
The Hepatitis A vaccine, Avaxim, protects against the virus in more than 95% of cases and provides protection from the virus for ten years. The vaccine contains inactivated Hepatitis A virus providing active immunity against a future infection.
Dosages and schedules for Hepatitis A vaccines
| Age | Dose (ELISA units) | Volume (mL) | No. of doses | Schedule (months) |
|---|---|---|---|---|
| 12 months–18 yrs | 720 | 0.5 | 2 | 0,6-12 |
| ≥19 years | 1,440 | 1.0 | 2 | 0,6-12 |
| Age | Dose (U.) | Volume (mL) | No. of doses | Schedule (months) |
|---|---|---|---|---|
| 12 months–18 yrs | 25 | 0.5 | 2 | 0,6-18 |
| ≥19 years | 50 | 1.0 | 2 | 0,6-18 |
Pre-exposure Vaccination
Hepatitis A vaccination is recommended for all children at age 1 year, for persons who are at increased risk for infection, for persons who are at increased risk for complications from Hepatitis A, and for any person wishing to obtain immunity. The following groups are recommended to receive Hepatitis A vaccination:
- All children at age 1 year (i.e., 12–23 months). Children who have not been vaccinated by age 2 can be vaccinated at subsequent visits.
- Children and adolescents ages 2–18 who live in states or communities where routine Hepatitis A vaccination has been implemented because of high disease incidence. Before 2006, when Hepatitis A vaccination was first recommended for all children at age 1 year, vaccination had been targeted to children living in states or communities that had historically high rates of Hepatitis A. States, counties, and communities with existing Hepatitis A vaccination programs for children aged 2–18 years are encouraged to maintain these programs. In those communities, new efforts focused on routine vaccination of children at age 1 year should enhance, not replace, ongoing programs directed at a broader population of children.
- Persons traveling to or working in countries that have high or intermediate rates of Hepatitis A. Persons from developed countries who travel to developing countries are at high risk for Hepatitis A. The risk for Hepatitis A exists even for travelers to urban areas, those who stay in luxury hotels, and those who report that they have good hygiene and that they are careful about what they drink and eat (see Hepatitis A and International Travel for more information).
- Men who have sex with men. Sexually active men (both adolescents and adults) who have sex with men should be vaccinated. Hepatitis A outbreaks among men who have sex with men have been reported frequently. Recent outbreaks have occurred in urban areas in the United States, Canada, and Australia.
- Users of illegal injection and noninjection drugs. During the past two decades, outbreaks of Hepatitis A have been reported with increasing frequency among users of both injection and noninjection drugs (e.g., methamphetamine) in North America, Europe, and Australia.
- Persons who have occupational risk for infection. Persons who work with HAV-infected primates or with HAV in a research laboratory setting should be vaccinated. No other groups have been shown to be at increased risk for HAV infection because of occupational exposure.
- Persons who have chronic liver disease. Persons with chronic liver disease who have never had Hepatitis A should be vaccinated, as they have a higher rate of fulminant Hepatitis A (i.e., rapid onset of liver failure, often leading to death). Persons who are either awaiting or have received liver transplants also should be vaccinated.
- Persons who have clotting-factor disorders. Persons who have never had Hepatitis A and who are administered clotting-factor concentrates, especially solvent detergent-treated preparations, should be vaccinated.
Serologic Testing
Pre-exposure
- Approximately one third of the U.S. population has serologic evidence of previous HAV infection, which increases with age and reaches 75% among persons aged more than 70 years.
- Screening for HAV infection might be cost-effective in populations where the prevalence of infection is likely to be high (e.g., persons aged more than 40 years and persons born in areas of high HAV endemicity).
- The potential cost-savings of testing should be weighed against the cost and the likelihood that testing will interfere with initiating vaccination.
- Vaccination of a person who is already immune is not harmful.
Post-exposure
- Persons who recently have been exposed to HAV and who previously have not received hepatitis A vaccine should be administered a single dose of single-antigen vaccine or immunoglobulin (IG) (0.02 mL/kg) as soon as possible.
- Information about the relative efficacy of vaccine compared with immunoglobulin postexposure is limited, and no data are available for persons aged more than 40 years or those with underlying medical conditions.
- Therefore, decisions to use vaccine or immunoglobulin should take into account patient characteristics associated with more severe manifestations of hepatitis A, including older age and CLD.
- For healthy persons aged 12 months to 40 years, single-antigen hepatitis A vaccine at the age-appropriate dose is preferred over immunoglobulin because of vaccine advantages, including long-term protection and ease of administration.
- For persons aged more than 40 years, immunoglobulin is preferred because of the absence of information regarding vaccine performance and the more severe manifestations of hepatitis A in this age group; vaccine can be used if immunoglobulin cannot be obtained.
- The magnitude of the risk for HAV transmission from the exposure should be considered in decisions to use immunoglobulin or vaccine.
- Immunoglobulin should be used for children aged less than 12 months, immunocompromised persons, persons who have had diagnosed CLD, and persons for whom vaccine is contraindicated.
- If immunoglobulin is administered to persons for whom hepatitis A vaccine also is recommended, a dose of vaccine should be provided simultaneously with immunoglobulin. The second vaccine dose should be administered according to the licensed schedule to complete the series. The efficacy of immunoglobulin or vaccine when administered greater than 2 weeks after exposure has not been established.