Development and efficacy assessment of combination vaccines, with emphasis on acellular pertussis.

The number of vaccines suitable for infant immunization is increasing, leading to a need to co-administer them in combination or combos. The recent demonstration of high efficacy against whooping cough using DTPa vaccines makes it desirable to administer combos such as DTPaHBIPVHib. For all vaccines included, surrogate markers for protection exist, except for pertussis. The field efficacy studies performed with DTPa vaccines did not allow the establishment of a correlate for protection. We propose to use detailed serology and cell-mediated immunity markers obtained from infant immunization studies, as well as a mouse intranasal challenge model, to monitor the immune responses induced by DTPa-combos.