STUDY OF PERTUSSIS VACCINES IN INFANTS - COMPARISON OF RESPONSE TO ACELLULAR PERTUSSIS DTP VACCINES CONTAINING 25 MU-G OF FHA AND EITHER 25OR 8 MU-G OF PT WITH RESPONSE TO WHOLE-CELL PERTUSSIS DTP VACCINE

Clinical and serological responses of infants to primary vaccination w ith diphtheriatetanus-acellular pertussis (DTPa) vaccines containing 2 5 mu g of filamentous haemagglutinin (FHA) and either 25 or 8 mu g of pertussis toroid (PT) were compared in a double-blind randomized study with responses of infants receiving whole-cell pertussis D TP vaccine (DTPw). In total, 308 healthy infants were enrolled to receive three vaccine doses at 3, 4 and 5 months of age. DTPa recipients had signifi cantly lower incidences of local reactions and fever than the DTPw rec ipients. No differences in reactogenicity were observed between DTPa g roups receiving 8 and 25 mu g closes of PT After vaccination, an immun e response to PT was seen in 96% of 25 mu g PT DTPa recipients, 94% of DTPw recipients and 86% of mu g PT DTPa recipients. The geometric mea n anti-PT neutralizing antibody titre was significantly higher for 25 mu g PT dose recipients (34.9 Chinese hamster ovary (CHO)) as compared with 8 mu g PT dose recipients (21.0 CHO). The results support the us e of the higher dose of PT in acellular pertussis vaccine preparations .