Colorado State University Extension
SafeFood Rapid Response Network


SAFEFOOD NEWS - Spring 1997 - Vol. 1, No. 3

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Recommendations for Hepatitis a Immunization

Hepatitis A virus, which is carried in fecal maker, can be transmitted by contaminated food or water. It is highly infectious, and can produce anything from mild flu-like symptoms to severe illness, jaundice, and liver damage, though people normally recover. Before vaccines, gamma globulin (immune globulin) was used for those who had been exposed to hepatitis A, or were likely to be exposed. The protection it gives is limited and short-term.

In the past two years, two inactivated hepatitis A virus (HAV) vaccines have been licensed in the U.S.: Havrix (SmithKline Beecham) and VAQTA (Merck). Both vaccines are highly immunogenic (able to induce antibodies) and able to prevent disease. Although desirable, combination vaccines that include HAV antigens are not currently available.

No serious adverse reactions have been attributed to havrix or VAQTA. The most common side effects are soreness at the injection site (56% for adults and 15% for children), and headache ( 14% and 4%, respectively).

Neither vaccine should be given to individuals allergic to alum; Havrix should not be given to those allergic to the preservative 2-phenoxyethanol. While the risk of giving these vaccinations to pregnant women has not been evaluated, as a killed vaccine the risk should be extremely low. No special precautions are recommended for immunocompromised patients.

Current recommendations for hepatitis A virus immunization from the Advisory Committee on Immunization Practices (ACIP) suggest vaccination for the following groups who are historically at increased risk for infections:

• Travelers. Immunization is recommended for persons two years or older who travel to countries other than Canada, U.S., Australia, Japan, New Zealand, and Western Europe.
• Children who live in Alaskan Native villages, American Indian reservations, and selected Hispanic or religious communities should be routinely vaccinated beginning at age two.
• Homosexual men.
• Users of illicit drugs, whether using injections or not.
• Occupationally challenged. The only occupational groups shown to be at increased risk for hepatitis A infection are those who work with HAV-infected primates or HAV in the research lab. No studies support routine vaccination of day care, health care, or sewage workers, or those who work with the developmentally disabled.
• Individuals with chronic liver disease. While not at increased risk for hepatitis A infection per se, this group is more likely to develop sudden and severe hepatitis, if infected. Those who are awaiting or have received liver transplants should also be vaccinated.
• Individuals with clotting-factor disorders.
• Residents of selected communities with very high incidence rates. Currently, widespread vaccination of residents of communities with intermediate incidence rates is typically not feasible. Targeting subgroups with the highest rate of disease may be considered, but the effectiveness of this effort has not been determined.

It is often asked whether food handlers should be required to be vaccinated. Contrary to popular perception, food handlers are not at increased risk for HAV infection, nor are people who eat out. Many people, including the media, often confuse public alerts about possible restaurant-associated exposures with actual restaurant-associated outbreaks, which are quite rare. Though the ACIP does not recommend that food handlers be vaccinated, they state that "consideration may be given to vaccinations [of food handlers at their employers' expense] . . . where . . . such vaccination is cost effective." Traditional recommendations about personal hygiene and proper food handling remain the best way to reduce the transmission of hepatitis A and other pathogens spread by the fecal-oral route.

Many Americans are immune to HAV because of past exposure; most of these have no history of infection. About one-third of U.S. residents older than 40 years are immune, and pre-vaccination screening of older individuals may be cost effective.

Source: CD Summary, Oregon Health Division (Adapted from CDC, Prevention of hepatitis A through active or passive immunization recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. 1996; 45(No. RR-15):1-25). UC Berkeley Wellness Letter, August 1996.

Updated Monday, August 29, 2011