Study: Whooping cough vaccine may not prevent infection

SILVER SPRING, Md. — A new study is helping to provide a better understanding of vaccines for whooping cough, the Food and Drug Administration announced Wednesday. Based on an animal model, the study shows that acellular pertussis vaccines licensed by the FDA are effective in preventing the disease among those vaccinated, but suggests that they may not prevent infection from the bacteria that causes whooping cough in those vaccinated or its spread to other people, including those who may not be vaccinated.

“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, 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.” 

While the reasons for the increase in cases of whooping cough are not fully understood, multiple factors are likely involved, including diminished immunity from childhood pertussis vaccines, improved diagnostic testing and increased reporting. With its own funds plus support from the National Institutes of Health, the FDA conducted the study to explore the possibility that acellular pertussis vaccines, while protecting against disease, might not prevent infection.

“There were 48,000 cases reported last year despite high rates of vaccination,” commented Anthony Fauci, director of the NIH’s National Institute of Allergy and Infectious Diseases. “This resurgence suggests a need for research into the causes behind the increase in infections and improved ways to prevent the disease from spreading.”

Whooping cough rates in the United States have been increasing since the 1980s and reached a 50-year high in 2012. Whooping cough is a contagious respiratory disease caused by Bordetella pertussis bacteria. Initial symptoms include runny nose, sneezing, and a mild cough, which may seem like a typical cold. Usually, the cough slowly becomes more severe, and eventually the patient may experience bouts of rapid, violent coughing followed by the “whooping” sound that gives the disease its common name, when trying to take a breath.

The study was published Nov. 25 in The Proceedings of the National Academy of Sciences.