[Revaccination against hepatitis B in non-responders and in under-responders in a group of mentally handicapped patients].

At 's Koonings Jaght, a community for the mentally handicapped, 330 inhabitants who were seronegative for hepatitis B markers, were vaccinated with a DNA recombinant vaccine. Following primary vaccination, 87% of the inhabitants had an anti-HBs titer of greater than or equal to 10 IU/l while 68% had a titer of greater than or equal to 100 IU/l. It appears from the literature that a certain percentage of the non-responders and hyporesponders still develop sufficient protective antibodies after revaccination, directly following primary vaccination. Besides, it is known from the literature that a titer greater than or equal to 100 IU/l provides prolonged protection. For these reasons, 105 inhabitants whose anti-HBs titers were lower than 100 IU/l following primary vaccination, received one to three additional boosters, depending of the level of the titer. After this revaccination, 92% of the inhabitants had titers greater than or equal to 10 IU/l while 81% had titers greater than or equal to IU/l. From the results of the study it appears that following direct revaccination of non-responders and hyporesponders an additional percentage still reach the protective level of greater than 10 IU/l and that a not inconsiderable percentage achieve a titer providing prolonged protection. The conclusion therefore is that it is useful to revaccinate mentally handicapped persons with no or with low seroconversions following primary vaccination.