Vaccination against hepatitis B in preschool children with Down's syndrome

. Twenty-nine healthy HBsAg- and HBsAb-negative children with Down's syndrome who were living at home (mean age 42 months; 19 M, 10 F) were vaccinated against hepatitis B virus either with recombinant DNA or plasma-derived vaccine. Both groups of children responded well to the vaccination schedules, with HBsAb seroconversion rates close to 100%. Vaccination against hepatitis B in preschool children with Down's syndrome is effective in spite of the existing abnormalities of the immune function.