Shortcomings of pertussis vaccines: why we need a third generation vaccine.

First generation whole-cell (wP) and second generation acellular (aP) pertussis vaccines have been highly effective in preventing childhood deaths due to pertussis, yet both vaccines have drawbacks that have limited their long-term usefulness. These include issues of reactogenicity and potency in the case of wP, and limited durability of protection and the potential for selection of escape mutants in the case of aP. Neither vaccine prevents disease in neonatal infants who continue to die from pertussis. A third generation of pertussis vaccines that provides broad, durable protection is needed. In the meantime, countries using wP should continue to do so, while countries using aP need to consider policies and schedules that reduce pertussis transmission to unvaccinated infants. In this respect, maternal vaccination appears to be a promising solution.