NON-EFFICACY OF LOW-DOSE INTRADERMAL VACCINATION AGAINST HEPATITIS-B IN DOWNS-SYNDROME

Persons with Down's syndrome (DS) constitute a risk group for hepatitis B (HB) and are recommended to be immunized. Of 123 persons with DS in Orebro county screened for markers of HB, 31% had such markers: 16% were potentially contagious. 83 persons without markers participated in a comparative trial of the immunogenicity of a recombinant HB vaccine given either intramuscularly (IM) or in a lower dose intradermally (ID). Immunity developed in 73% after IM vaccination as compared to 29% of those given ID vaccination (p < 0.005). At 3-year follow-up half and two-thirds of the immune persons, respectively, had lost their immunity. Those > 30 years had a poor immunization response compared to the younger ones (p < 0.01). Only 19% of the non-responders developed immunity after an IM booster dose given 10 months after the third injection. Intradermal vaccination is not warranted in persons with DS, especially not in middle aged and older persons. A booster dose of vaccine does not ascertain immunity in those who do not respond with immunity to the ordinary immunization shedule. Post-vaccination immunity should therefore be controlled.