Introduction: The aim of this study was to investigate the prevalence and risk factors associated with hepatitis A virus (HAV) infection in a representative population sample to determine who can benefit from vaccination strategies and to investigate the age limit at which previous HAV antibody screening is not required.
Methods: From April to September 2002, we studied a total of 557 patients, 90 children and 467 blood donors, aged 1-65 years. Information on demographic variables (age, gender, place of residence and education level) was recorded. Patients with history of hepatitis or other liver diseases were excluded. Anti-HAV antibodies (IgG) were determined with an automated enzyme immunoassay (AxSYM, Abbott Diagnostics). The chi-square and Mantel-Haenszel tests were used for the statistical analysis.
Results: The overall prevalence of HAV infection was 41.5%. There was a significant increase in prevalence with age (chi-square TL:205, P < .0001), with rates from the youngest to oldest groups of 5.5%, 23.5%, 28.1%, 64.2% and 93.2%, respectively. Apart from age, the only other risk factor independently associated with prevalence was the level of education, with higher prevalence at the lower education levels (OR 5 2.7; chi-square = 32.11, P < .0001).
Conclusions: The prevalence of anti-HAV antibodies has decreased in recent years in the community of Madrid. Among the population less than 35 years of age, 75% of individuals are susceptible to the infection and could benefit from universal vaccination without previous screening for anti-HAV antibodies.