SAFETY AND IMMUNOGENICITY OF AN ACELLULAR PERTUSSIS DIPHTHERIA TETANUS VACCINE GIVEN AS A SINGLE INJECTION WITH HAEMOPHILUS-INFLUENZAE-B CONJUGATE VACCINE

To determine if an acellular pertussis-diphtheria-tetanus vaccine coul d be combined with a Haemophilus influenzae b conjugate vaccine as a s ingle injection, we randomized 468 children between 17 and 21 months o f age previously immunized with three doses of each vaccine to receive a five-component acellular pertussis vaccine combined with diphtheria and tetanus toxoids, and Haemophilus influenzae b-tetanus toroid conj ugate vaccine either as separate injections on separate clays, separat e injections on the same day, or as a single combined injection. Rates of adverse reactions were similar amongst the groups except for incre ased injection site tenderness (29.2% vs 17%, RR 1.76, 95% CI 1.09-2.8 5) and fussiness (36.4% vs 23.3%, RR 1.59, 95% CI 1.05-2.41) in the gr oup given the combined injection rather than separate injections on se parate days. Antibody levels against the capsular polysaccharide of H. influenzae b after the single combined injection (47.1 mu g ml(-1)) w ere lower than after separate injections on the same day (66.0 mu g ml (-1); P<0.05) but higher than when the injections were administered on separate days (28.4 mu g ml(-1); P<0.001). We conclude that the five- component acellular pertussis vaccine is safe and immunogenic when com bined with diphtheria and tetanus toxoids and H. influenzae b-tetanus toroid conjugate vaccine in children receiving the fourth dose of the immunization series. (C) 1997 Published by Elsevier Science Ltd.