The question is examining the feasibility of using fractional dose of the
wP containing vaccine to protect adolescents and adults. In an era of
combination vaccines where different antigens are being licensed for
mixing with other antigen/combination manufactured separately- some even
at different production units (for example DTP+Hep B with Hib conjugate
vaccine), the suggestion of Dr Paul seems quite tempting and worth
considering, especially for our country where significant disease burden
coupled with exorbitant cost of the aP vaccines make it impossible to even
think of exercising the option of using aP vaccines at mass level.
However, to recommend such a practice, we need to have evidence of safety
as well as of efficacy of the revised practice that can only be obtained
through clinical trials. Further, the effect of such practices on the
frequency of serious adverse events and on protection against disease has
not been determined earlier. Hence, in the absence of such a data, IAPCOI
can not recommend this alternative practice of using fractional dose of
whole-cell pertussis vaccine for adolescent and adult vaccination.
Vijay Yewale and Vipin Vashishtha
IAP Committee on Immunization 2009-10.