The shift in prevalence of hepatitis A immunity in Flanders, Belgium.
The purpose of this study was to obtain data on the prevalence of hepatitis A in Flanders, Belgium, in order to analyse any change in the epidemiological pattern of hepatitis A virus (HAV) in the region, and to determine at which age pre-vaccination testing would be useful. To meet these goals, a sero-epidemiological survey was conducted: 4058 serum samples were collected from a random sample of the general population in 1993-94. The overall age-standardised prevalence was 51.3%. Among non-Belgians (N = 245), the age-standardised anti-HAV prevalence was 66.4%, significantly higher than the 49.6% anti-HAV prevalence found in Belgians (N = 3186). Among Belgians, seroprevalence increased with age: from 5.4% in the youngest age group (0-14 years) to over 80% in the two oldest age groups (55-64 years and > or = 65 years). Prevalence rates were as high as 31.7% in the 25-34 year old age category, and 60.8% in the 35-44 year old age category. The age-specific prevalence figures among Belgians and non-Belgians reflect two different epidemiological patterns: the epidemiological pattern of a low endemic region for Belgians and the epidemiological profile of an intermediate endemic region forn non-Belgians. The age-specific prevalence figures in Belgians were compared with the 1979 and 1989 anti-HAV prevalence figures in Belgian first-time blood donors. A clear epidemiological shift showing decreasing HAV prevalence in the youngest age groups was found. If we accept that pre-vaccination screening is useful at a 35% prevalence rate, all persons over 35 years of age should be screened before vaccination.
Beutels
M
M
WHO Collaborating Centre for Prevention and Control of Viral Hepatitis, Department of Epidemiology and Community Medicine, University of Antwerp, Wilrijk, Belgium.
Van Damme
P
P
Vranckx
R
R
Meheus
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D001530:Belgium / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology* / Q000276:immunology; D035922:Hepatitis A Antibodies; D006508:Hepatitis Antibodies / Q000097:blood*; D006507:Hepatovirus / Q000276:immunology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012494:Sampling Studies; D016036:Seroepidemiologic Studies
D035922:Hepatitis A Antibodies; D006508:Hepatitis Antibodies