Developing the Pertussis Vaccine (DTP): The Fascinating History of 3 Women Who Changed Vaccine Research
An effective vaccination protocol remains the best way to prevent pertussis or whooping cough. Disease rates are highest in regions where vaccination rates are low. In developed countries, pertussis incidence is highest in unvaccinated babies and adolescents.
Before the vaccine, pertussis had a high cumulative incidence, and the mortality rate was one death per ten cases. More children died of pertussis annually in the United States than of polio and measles combined.
The story of the vaccine is that of three women with an uncompromising resolve to help solve the whooping cough crisis in the United States. Pearl Kendrick, Grace Eldering, and Loney Gordon changed the face of vaccine research and clinical study protocols and helped save millions of lives.
“We learned about the disease and the depression at the same time.”
– Grace Eldering, co-developer of the DTP vaccine.
In the 1930s, Pearl Kendrick and Grace Eldering began their whooping cough research project in hopes of creating a vaccination at the Michigan Department of Health laboratory in Grand Rapids, Michigan, USA. Both Kendrick and Eldering had been infected with pertussis as children, and these experiences played a strong role in driving their research. They hired Loney Gordon, an African-American researcher, to support their efforts.
A virulent strain had infected many children in Grand Rapids. Each day, after completing their scheduled laboratory work, Kendrick and Eldering went door to door and collected samples of the pathogen cells from these sick children. They developed strong partnerships with local physicians to get informed about infections and visited poverty-stricken families to collect thousands of samples. This type of field outreach was not common since study protocols were not well-defined at the time.
Using these samples, the women found funding for and ran a large-scale clinical trial during the Great Depression, the longest and worst economic crisis we’ve seen so far, and World War II. Many research studies were severely underfunded and even halted. However, Pearl and Eldering gathered funding from several organizations, including First Lady Eleanor Roosevelt’s Works Progress Administration (WPA). After a three-year trial, the DTP vaccine was declared a success.
Image: Chart depicting worldwide DTP vaccine coverage (WHO-UNICEF).
Gordon was a significant contributor to the success of the DTP vaccine development. This type of Bordetella is notoriously difficult to grow in a lab. Still, Gordon tested thousands of cultures and identified sheep blood as a critical factor to incubate the culture in a lab. Her research was instrumental in helping Kendrick and Eldering find a strong Bordetella strain effective for the DTP vaccine  .
This discovery helped them create a rapid cough plate diagnostic tool. Local physicians could send their cough plates to the lab for analysis. This innovation helped the Kendrick-Eldering-Gordon team learn about when a child would be most infectious, the initial three-week infection period. They also figured out that infected children posed no threat to others after five weeks.
This groundbreaking research and the success of the clinical trial helped save the lives of millions of children worldwide. While their clinical trial methodology underwent significant scrutiny from the medical profession, the discussion led to a more robust methodology and protocols.
Even initial skeptics were eventually convinced of the effectiveness of the vaccines. The most prominent of them was Wade Hampton Frost, an epidemiologist from Johns Hopkins University and the head of the American Public Health Association (APHA). While Frost was critical at first, he accepted Kendrick and Eldering’s results   .