A Critical Evaluation of Whole Cell Pertussis Vaccines on their Composition and Efficacy in Comparison to Acellular Pertussis Vaccines

Abstract

Diphtheria-Tetanus-Pertussis vaccine has been included in the National Immunization Schedule. DTP vaccines that have been developed can be broadly classified based on the pertussis component i.e. 'The whole cell pertussis vaccine' (wP) and 'The acellular pertussis vaccine' (aP) which contains only specific antigens of Bordetella pertussis. But, mere presence of more or less antigenic components does not determine their efficacy. During the period 1991 to 1996, the western world gradually transitioned from the whole cell pertussis vaccine to the acellular pertussis vaccine. However, there was an increase in cases of pertussis in western countries in the first decade of 21st century, making pertussis the only vaccine preventable disease on rise. The durability of protection with acellular vaccine is not as good as with whole cell vaccine. The acellular pertussis vaccine's failure to deliver durable infection to children had also led to the 2010 California epidemic.The aP vaccine is devoid of crucial antigens participating in the pathogenesis of disease unlike wP vaccine and has slightly lower reactogenicity, thus lower efficacy. Therefore, the duration of protection after immunization by wP vaccine is more as compared to aP vaccine and the average longest protection lasts for about 10-12 years. The wP vaccine also confers cross immunity against B. parapertussis which the aP vaccine does not.