title: The latest seroepidemiological pattern of hepatitis A in Japan.
abstract: Age-specific prevalence of anti-hepatitis A virus antibody (anti-HAV) was surveyed with 2,708 sera collected in 1994 in various areas of Japan. By age-group analyses, we found strong association of anti-HAV antibody with higher age group. The prevalence ratios of antibody in the groups of 30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64 and 65 years or older were 0, 4.2, 22.0, 44.8, 57.6, 76.4, 84.5 and 91.4%, respectively. Geometric mean titers of anti-HAV antibody in the positive age groups were approximately 6,000 mIU/ml. The seropositives among older population were ascribed to the infections more than 40 years ago and the high anti-HAV titers have been maintained since that time. In Japan, people younger than 40 years of age are extremely risky to HAV infection, since 99% have no antibody. Those in forties are also risky since two-thirds of them are seronegative. In Japan, an inactivated vaccine was licensed in 1994. Vaccination may be recommended for such high-risk groups as travelers going to endemic areas, patients who have received blood product medication and child-care staffs.
authors.affiliation: Department of Viral Disease and Vaccine Control, National Institute of Infectious Diseases, Tokyo.
authors.forename: T
authors.initials: T
authors.lastname: Kiyohara
authors.forename: T
authors.initials: T
authors.lastname: Satoh
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.forename: A
authors.initials: A
authors.lastname: Totsuka
authors.forename: Y
authors.initials: Y
authors.lastname: Moritsugu
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D005843:Geography; D006506:Hepatitis A / Q000453:epidemiology*; D035922:Hepatitis A Antibodies; D006508:Hepatitis Antibodies / Q000097:blood*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D012737:Sex Factors
chemical_list: D035922:Hepatitis A Antibodies; D006508:Hepatitis Antibodies