Prevalence of Hepatitis A Antibody in Travelers from Hawaii.

Background: Hepatitis A is the most frequent vaccine-preventable infection in travelers to developing countries. Hepatitis A vaccine and immune serum globulin (IG) offer safe, effective protection against hepatitis A. Some travelers are already immune, however, and it is useful to try to identify subgroups with an anticipated high prevalence of antibody to hepatitis A (anti-HAV). Screening for antibody in these groups would often be a cost-effective alternative to routine use of hepatitis A vaccine or IG prior to travel. Methods: Prospective travelers to developing countries from Hawaii (n = 476) were tested for anti-HAV. Total antibody was measured by an enzyme immunoassay. Age, sex, birthplace, previous travel experience, and past history of hepatitis or jaundice were recorded for each traveler. Results: Overall prevalence of anti-HAV was 35.3%. Antibody prevalence increased progressively with age and varied significantly with birthplace and travel experience. Antibody prevalence was particularly high in travelers with a history of hepatitis or jaundice. Conclusions: Screening for preexisting immunity to hepatitis A is often worthwhile in extended stay or repeat travelers. This study suggests that screening may also be a cost-effective alternative to routine use of hepatitis A vaccine or IG in those travelers (i) born in the United States (including Hawaii) before 1930; (ii) born in Europe, Australasia, or Japan before 1950, (iii) born in developing countries; (iv) with increased travel experience; and (v) with a history of hepatitis or jaundice.