New findings could improve future whooping cough vaccine

Researchers at Trinity College Dublin recently made novel discoveries related to the vaccine for whooping cough, also called pertussis, that could improve vaccines in the future, according to a study published in PLoS Pathogens.

Kingston Mills and his research team at the School of Biochemistry and Immunology in the Trinity Biomedical Sciences Institute in Ireland found that the whole cell pertussis vaccine induces a stronger cellular immune response than the acellular vaccine. While the whole cell vaccine is much more likely to cause adverse reactions, the vaccine induces a strong immune response mediated by white blood cells called Th1 cells.

The researchers found the acellular pertussis vaccine induced weaker immunity mediated by antibodies and the Th17 cell. The induction of Th1 cells may be required for optimum protective immunity against the bacteria.

Mills and his team found that by changing the vaccine-boosting adjuvant used for the acellular pertussis vaccine, from alum to an adjuvant based on bacterial DNA, the vaccine could induce the necessary Th1 cells and improve efficacy of the vaccine against pertussis. The new resulting vaccine could combine the safety profile of the acellular vaccine with the Th1 protection of the whole cell vaccine.

"Although it will not be an easy task to implement, our findings should pave the way for an improved vaccine against whooping cough in children," Mills said.

The acellular pertussis vaccine was introduced to most developed countries more than a decade ago. Prior to the use of the acellular vaccine, the whole cell pertussis vaccine was made to prevent infants and children from getting infected. The new vaccine has been safer but protective immunity conferred by the vaccine falls quickly, causing the need for frequent booster vaccinations.

The drop in immunity conferred by the acellular vaccine may be a contributing factor to a growing number of whooping cough cases in the U.S., the Netherlands and Australia.