Hepatitis A Vaccine

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     To the Editor: Since clinical practice and guidelines for the prevention of hepatitis A by vaccination in Europe differ slightly from those in the United States, we would like to make some comments to complement the article by Craig and Schaffner on this topic (Jan. 29 issue).1 First, hepatitis A vaccines are licensed in Europe for children one year of age or older. Indeed, the safety and immunogenicity of hepatitis A vaccines in young children have been well documented.2 Moreover, although the presence of maternal antibodies diminishes the vaccine antibody response, even in infants the immune system can be adequately primed, as Craig and Schaffner indicate.1

    Second, because hepatitis A vaccines elicit protective antibodies after two to three weeks (within the incubation period of the disease) and because the availability of immune globulin is limited in many European countries, vaccination against hepatitis A should be considered the preferred method of preexposure prophylaxis, even for the traveler whose departure is imminent.3

    Koen Van Herck, M.D.

    Pierre Van Damme, M.D., Ph.D.

    University of Antwerp

    B-2610 Antwerp, Belgium

    koen.vanherck@ua.ac.be

    Editor's note: The authors report having received funding from Aventis Pasteur MSD, Berra Biotech, GlaxoSmithKline Biologicals, Merck, and Wyeth.

    References

    Craig AS, Schaffner W. Prevention of hepatitis A with the hepatitis A vaccine. N Engl J Med 2004;350:476-481.

    Abarca K, Ibanez I, Flores J, Vial PA, Safary A, Potin M. Vaccination against hepatitis A in children aged 12 to 24 months. Arch Med Res 2001;32:468-472.

    Connor BA, Van Herck K, Van Damme P. Rapid protection and vaccination against hepatitis A for travellers. BioDrugs 2003;17:Suppl 1:19-21.

    To the Editor: I applaud Craig and Schaffner's proposal that "the universal vaccination of children for hepatitis A be extended to the entire United States, starting at two years of age, with catch-up immunization for all older children through adolescence." Hepatitis A is one of the most common vaccine-preventable diseases reported in the United States. Recent statistics from the Centers for Disease Control and Prevention (CDC) indicate a decline in the rates of hepatitis A in the United States, secondary to the use of hepatitis A vaccine. The rates of infection in several eastern states where vaccination was not previously recommended now approximate the rates in several western states that in the past reported the highest rates of infection, but that instituted vaccination.1 The hepatitis A virus does not recognize county, state, or international borders. The ease of travel and shipment of produce between areas of high and low endemicity allows for ready transmission of hepatitis A. The hepatitis A vaccines have been proved safe, efficacious, and cost effective.2 We have the means to eradicate hepatitis A in the United States if we are willing to spend the resources necessary for mass immunization. Vaccination is the key.

    Philip Rosenthal, M.D.

    University of California, San Francisco

    San Francisco, CA 94143

    prosenth@peds.ucsf.edu

    Editor's note: Dr. Rosenthal chairs the American Liver Foundation's hepatitis A vaccine initiative. He has testified on behalf of hepatitis A vaccine legislation before the California, Nevada, and New Mexico State Assembly and Senate Health Committees. He is a consultant to GlaxoSmithKline, one of the manufacturers of hepatitis A vaccine.

    References

    Centers for Disease Control and Prevention. Hepatitis A virus: top 10 states with the highest hepatitis A rates. (Accessed April 15, 2004, at http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_a/slide_46.htm.)

    Rosenthal P. Cost-effectiveness of hepatitis A vaccination in children, adolescents, and adults. Hepatology 2003;37:44-51.

    The authors reply: Drs. Van Herck and Van Damme point out that European countries have licensed the hepatitis A vaccine for use in children starting at the age of one year. The ability to give the first dose at the one-year well-child visit would make it much easier to integrate the hepatitis A vaccine into the routine childhood immunization schedule in this country. Several studies have documented the immunogenicity and safety of hepatitis A vaccine in children under two years of age.1,2,3,4,5 Studies of the efficacy of the vaccine in children under two years of age are now under way in the United States, and the results will be important for future deliberations concerning the use of hepatitis A vaccine among children in this age group.

    The authors also suggest that in European countries hepatitis A vaccine should be the preferred method of preexposure prophylaxis before international travel. This seems to be a reasonable approach in Europe, where immune globulin is not readily available. Given the availability of immune globulin in the United States, the CDC continues to recommend hepatitis A immunization and concurrently administered immune globulin for persons traveling from the United States to countries with high rates of hepatitis A if travel is to occur within four weeks of vaccination (www.cdc.gov/travel/diseases/hav.htm); some travel clinics rely solely on the vaccine if departure is planned more than two weeks after immunization.

    We agree with Dr. Rosenthal that universal vaccination is the best approach to the elimination of hepatitis A in the United States.

    Allen S. Craig, M.D.

    Tennessee Department of Health

    Nashville, TN 37247

    William Schaffner, M.D.

    Vanderbilt University School of Medicine

    Nashville, TN 37232

    william.schaffner@vanderbilt.edu

    References

    Abarca K, Ibanez I, Flores J, Vial PA, Safary A, Potin M. Vaccination against hepatitis A in children aged 12 to 24 months. Arch Med Res 2001;32:468-472.

    Fiore AE, Shapiro CN, Sabin K, et al. Hepatitis A vaccination of infants: effect of maternal antibody status on antibody persistence and response to a booster dose. Pediatr Infect Dis J 2003;22:354-359.

    Letson GW, Shapiro CN, Keuhn D, et al. Effect of maternal antibody on immunogenicity of hepatitis A vaccine in infants. J Pediatr 2004;144:327-332.

    Bell BP, Negus S, Fiore A, et al. A comparison of the effect of age on hepatitis A vaccine immunogenicity among infants with and without passively-transferred maternal antibody. In: Abstracts of the 40th Annual Meeting of the Infectious Diseases Society of America, Chicago, October 24–27, 2002. Alexandria, Va.: Infectious Diseases Society of America, 2002:134. abstract.

    Dagan R, Amir J, Mijalovsky A, et al. Immunization against hepatitis A in the first year of life: priming despite the presence of maternal antibody. Pediatr Infect Dis J 2000;19:1045-1052.

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