Background: The aim of this study was to assess the seroprevalence and the risk factors of hepatitis A virus (HAV) infection in the population from Gran Canaria (Spain) and to determine at which age pre-vaccination testing would be useful.
Methods: A transversal observational study of the presence of HAV antibodies (IgG) on serum samples obtained from a population ranging from 8 months to 63 years old was performed between January 1995 and December 1996. IgG anti-HAV were detected by a commercial immunoenzyme assay. The study included 547 persons resident in Gran Canaria. Epidemiological data (age, sex, number of family members, educational level, urban/rural residence and previous history of hepatitis) were gathered through a personal interview. Confusing variables were excluded by mean a multiple logistic regression analysis.
Results: Global prevalence of anti-HAV (IgG) was 36.0% (CI 95% 32.0-40.0). The prevalence of anti-HAV increased significantly with age from 2.3% in children under 4 years until 98.9% in older than 40 years (OR 3956.0; CI 95% 241.7-64,753.5). Only three independent data (age, sex and educational level) were significantly associated with HAV seroprevalence. A previous history of hepatitis A was present only in 4.8% of HAV-positive subjects.
Conclusions: The low prevalence of anti-HAV (IgG) in persons under 25 years old suggest that in the adolescent population the implementation of universal vaccination programs is recommended even without previous serologic screening. Otherwise, the results suggest that HAV prevaccination screening in our geographical were must be limited to subjects older than 25 years.