Acellular vaccines for preventing whooping cough in children.

Abstract

Routine use of whole cell pertussis vaccines was suspended in some countries in the late 1970s and early 1980s, leading to a resurgence of whooping cough. Acellular pertussis vaccines containing purified or recombinant Bordetella pertussis antigens were developed in the hope that they would be as effective but less toxic than the whole cell vaccines. The objective of this review was to assess the effects of acellular pertussis vaccines in children. The Cochrane Controlled Trials Register and Medline were searched up to January 1998. Double-blind randomised efficacy and safety trials of acellular pertussis vaccines in children, with active follow-up of participants and laboratory verification of pertussis cases. One reviewer assessed trial quality and extracted data. Six efficacy trials and 45 safety trials were included. Acellular pertussis vaccines with three or more pertussis vaccines were more effective than those with one or two antigens. They were also more effective than one type of whole cell pertussis vaccine, but less effective than two other types of whole cell vaccines. Differences in trial design precluded pooling of the efficacy data and results should be interpreted with caution. Most systemic and local adverse events were significantly less common with acellular than with whole cell pertussis vaccines. Multi-component acellular pertussis vaccines are effective, and show less adverse effects than whole cell pertussis vaccines. However in areas where whooping cough is more likely to be fatal, the higher toxicity of some whole cell vaccines may be offset by their increased effectiveness.