Immunoresponse to routine hepatitis B vaccination in pre-adolescents in the province of Guadalajara, Spain

Background: Although hepatitis B vaccine has been available in Spain since 1986, acute and chronic hepatitis B virus infection remains a public health problem. The comprehensive national strategy to prevent hepatitis B virus transmission includes hepatitis B vaccination of pre-adolescents. Our objec tive was to investigate the immunoresponse to routine hepatitis B vaccinati on in pre-adolescents in the province of Guadalajara and to study the relat ionship between the immunoresponse and other variables such as height, weig ht, Quetelet index, sex and home environment (rural or urban). Methods: We considered a cross-sectional descriptive study in the school population of eighth year primary education. Hepatitis B recombinant vaccine immunorespon siveness was studied in 338 students vaccinated with a 0, 1 and 6 months va ccination schedule. Anti-hepatitis B post-vaccination titres were quantifie d considering levels of protection greater than or equal to 10 Ul l(-1). Re sults: The seroprotection rate was 97,6%. The response of more than 46% of the children was very satisfactory and their anti-hepatitis B post-vaccinat ion titres exceeded 1000 Ul l(-1). No statistically significant differences could be found between sexes. The relation study between anti-hepatitis B post-vaccination levels and Quetelet index showed a statistically significa nt inverse correlation (p<0.001). Conclusions: Obesity is a predictor of po or immunoresponse and this response is not influenced by sex. We consider t he seroprotection that this vaccine offers to pre-adolescents to be excelle nt.