[Coverage and immune response to systematic hepatitis B vaccination in preadolescents of the city of Elche]. / Cobertura e inmunorrespuesta a la vacunación sistemática antihepatitis B en preadolescentes de la ciudad de Elche.

ABSTRACT

OBJECTIVE: To know the coverage of the systematic program of hepatitis B vaccination in the population of 7th year primary school children (12 years old) in the city of Elche. To investigate the immune response to the vaccine, and the length of protection according to this response. To study the relationship between the immune response and other biological variables such as height, weight, Quetelet index and sex. DESIGN: Cross-sectional study. SETTING: In a school community. PARTICIPANTS: The first five students of 7th in all the official class lists (110) from each school (53) were selected. The immune response was studied in 427 students. MAIN RESULTS: The 84.36 +/- 4 were correctly vaccinated (95 percent confidence level). A month after the booster dose, the antibodies HBs titres were quantified, considering levels of protection > or = 10 mU/ml. We found that Quetelet index and the antibody response were inversely correlated (p = 0.015). Sex was not a significant predictor of lack of detectable antibody response. 100% of correctly vaccinated children reached protective titres of antibodies, and 54% of them would be protected for 9 years or more. CONCLUSIONS: We consider the coverage satisfactory and excellent the seroprotection that this vaccine offers to these children. We suggest, to this population, a booster dose 10 years after the first vaccination.