Acellular pertussis (aP) vaccine fails to prevent colonization or transmission, a fact that provides a plausible explanation for the resurgence of pertussis, according to research published in The Proceedings of the National Academy of Sciences. The authors believe that optimal control of pertussis requires the development of improved vaccines.

“This study is critically important to understanding some of the reasons for the rising rates of pertussis, and informing potential strategies to address this public health concern,” said Karen Midthun, MD, director of the FDA’s Center for Biologics Evaluation and Research, where the study was conducted. “This research is a valuable contribution and brings us one step closer to understanding the problem. We are optimistic that more research on pertussis will lead to the identification of new and improved methods for preventing the disease.”

For the study, investigators vaccinated two groups of baboons at ages two, four, and six months. One group was given a whole-cell pertussis vaccine while the other group was treated with an acellular pertussis vaccine currently used in the United States.

After surveying the two groups, the researchers found that both types of vaccines generated robust antibody responses in the animals, and none of the vaccinated animals developed outward signs of pertussis disease after being exposed to B. pertussis. However, animals that received an aP vaccine had the bacteria in their airways for up to six weeks and were able to spread the infection to unvaccinated animals. The baboons that received whole-cell vaccine cleared the bacteria within three weeks.