Declining hepatitis A seroprevalence in adults in Catalonia (Spain): a population-based study.
BACKGROUND
One of the main uses of seroprevalence studies it to evaluate vaccination programmes. In 1998, a programme of universal vaccination of preadolescents in schools with the hepatitis A vaccine was begun in Catalonia. The objective of this study was to investigate the prevalence and risk factors of hepatitis A virus infection (HAV) in a sample of the adult population of Catalonia in 2002 and to evaluate the changes with respect to a survey carried out in 1996.


METHODS
The prevalence of HAV antibodies was determined by a third generation competitive immunometric assay in a representative sample of 1292 people aged >15 years. The association between the prevalence and different sociodemographic variables was determined by multiple logistic regression analysis.


RESULTS
The standardized global prevalence of HAV antibodies in 2002 was 68.2%, increased with age (p < 0.0001) and was associated with being born outside Catalonia (OR: 1.75; 95% CI 1.11-2.76) and lower social class (OR: 1.14; 95% CI 1.05-1.25). Compared with the last survey carried out in 1996 the standardized global prevalence was lower (68.2% vs 77.8%; p < 0.0001) as was the prevalence in people under 45 years.


CONCLUSIONS
The prevalence of the hepatitis A virus is decreasing in the adult population of Catalonia, especially in the younger age groups. The programme of vaccination of adolescents begun in 1998 to control the disease can provide indirect protection to the unvaccinated population.
Domínguez
Angela
A
Directorate of Public Health, Generalitat of Catalonia, Travessera de les Corts, Barcelona, Spain. angela.dominguez@ub.edu
Bruguera
Miquel
M
Plans
Pere
P
Espuñes
Jordi
J
Costa
Josep
J
Plasencia
Antoni
A
Salleras
Lluis
L
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D005260:Female; D006506:Hepatitis A / Q000097:blood* / Q000453:epidemiology* / Q000517:prevention & control; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000008:administration & dosage / Q000276:immunology; D030041:Hepatitis A virus / Q000276:immunology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016036:Seroepidemiologic Studies; D013030:Spain / Q000453:epidemiology
D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines