[The prevalence of markers for the hepatitis A and B viruses in the population of Gijón between 6 and 25 years old]

Background: The aim of this study was to know the prevalence of previous infection markers for hepatitis A and B viruses in a pediatric-juvenile population from Gijón, Spain.
Patients and methods: A representative (according to the census) transversal randomized sample of a population from 6 to 25 years in age from Gijón, Spain, was included in the study analyzing demographic, epidemiologic and clinical variables, liver tests, anti-HAV IgG and anti-HBc.
Results: Of the 630 individuals selected a demographic error was detected in 28 (4.4%) and 453 subjects were studied (71.9%) in whom the anti-HAV IgG was positive in 37 cases (8.75% of prevalence adjusted for age), with 4.4% (12/271) (CI 95% 2.3%-7.6%) for the younger cases and 13.7% (25/182) (CI 95% 9.1%-19.6%) in the group ranging from 18 to 25 years in age (p < 0.001). No anti-HAV IgG positive case was detected in the population under the age of 10 years. Among the young adults the prevalence of anti-HAV IgG positive cases was higher in those born in the south of Spain (2/6, 33.3%) (CI 95% 4.3%-77.7%) with respect to those from the northern regions of Spain (9/259, 3.5%) (CI 95% 1.6%-6.4%). (p = 0.02). With respect to HBV markers, of the 433 unvaccinated cases, 6 (1.4%) presented markers of past infection and 2 (0.46%) HBsAg positivity. Both had normal serum ALT without viral replication. Six cases of hypertransaminasemia levels (1.3%) were detected all being related with obesity or alcoholism. All the cases with previous acute clinical hepatitis were found to be anti-HAV IgG positive and anti-HBc negative.
Conclusions: The current prevalence of anti-HAV IgG in the population from 6 to 25 years from Gijón, Spain is very low and given the high degree of susceptibility (86%) for HAV infection in the young adult population (18-25 years) the implementation of vaccination programs is recommended even without previous serologic screening. The low prevalence of anti-Hbc would also undervalue its use as prevaccination screening against HB in this geographical area.