A large percentage of the Spanish population under 30 years of age is not protected against hepatitis A

A seroepidemiological study was conducted to assess the seroprevalence of hepatitis A (HAV) antibodies in the Spanish general population in 1992–93. A total of 2744 subjects (1337 men and 1437 women) in the 5–59 years age range were stratified by gender and age (5–12, 13–19, 20–29, 30–39, 40–49, 50–59 years). The presence of total anti-HAV antibodies was investigated using a commercial enzyme immunoassay. Fifty-five percent (95% CI: 53.5–57.2%) of the subjects were positive for anti-HAV antibodies, the age-standardized anti-HAV prevalence being 65.4%. Prevalence of seropositive subjects increased with increasing age (χ2 = 996,17; P < 0.0001), being 11%, 25% and 54% for the 5–12, 13–19 and 20–29 age groups respectively. The results from this study showed a remarkable decline in seroprevalence rates among children, adolescents and young adults. The large number of susceptible subjects in these groups of the population has public health implications in a country with intermediate HAV prevalence. J. Med. Virol. 60:363–366, 2000. © 2000 Wiley-Liss, Inc.