Pearl Kendrick, an American bacteriologist, helped co-develop the vaccine for whooping cough.
In addition to this breakthrough, she also contributed towards improving the international vaccine standards to promote better health protection.
Early Life and Educational Background
Pearl Louella Kendrick was born on August 24, 1890; when she turned three years old, she caught whooping cough. In those days the infection was known as “pertussis”, named after the bacteria Bordetella pertussis that causes the disease. Around 45 years later she had her revenge by developing the very first anti whooping cough vaccine.
Pearl’s father was a preacher, and in 1908, she graduated from high school. She first attended Greenville College where she stayed for a year before moving to Syracuse University where she received her diploma in 1914. Later, in 1934, she also graduated from Johns Hopkins University with her doctorate in bacteriology.
Pearl Kendrick’s Quest to Fight Whooping Cough
Whooping cough during is a highly contagious bacterial disease that mainly affects children. It causes long bouts of coughing and choking, making it difficult to breathe. The “whoop” is caused by gasping for breath after each bout of coughing. By the 1920s, it was claiming more than 6000 lives in the United States alone. In the 1940s, whooping cough was responsible for more infant deaths in the USA than measles, polio, and tuberculosis combined. The effects caused by whooping cough were so alarming that infected children were quarantined for at least two weeks while wearing a yellow armband which had the words “whooping cough” in big black letters.
Having been affected by this condition was one of Kendrick’s motivations to find a solution to counter whooping cough. In 1926 she started working at the newly opened Western Michigan Branch Laboratory of the Michigan Department of Health in Grand Rapids of Michigan. During this time, she began to immerse herself in concerns about public health and worked her way towards her doctorate in microbiology.
While working at Western Michigan Branch Laboratory, Kendrick met Grace Elderling who later partnered in discovering the vaccine for whooping cough. Kendrick had a heart for promoting better children’s health programs and with Elderling, they became perfect team. However, it was the 1930s, the time of the Great Depression, and because of this, funding for research as well as making programs realities were scarce—a major challenge which the team faced.
This did not, however, stop Kendrick and Elderling from developing the vaccine for whooping cough—something which they actually achieved after their routine laboratory work was completed. In 1932 when she started the whooping cough research project, it began as a fun engagement which later on turned out to be something which saved millions of lives.
Kendrick used the Grand Rapids as her clinical trial area and she worked with a team of local physicians to develop the vaccine along with Elderling. Samples of the pertussis bacillus were collected from the physicians in the area and methods were explored to inactivate it and create a safe vaccine. These same physicians also were first to be given the very first test vaccines.
Times were hard because of the lack of funding, but this didn’t prevent Kendrick who wanted to help improve the lives of those who were potentially going to be affected by whooping cough. In 1936, Kendrick had the opportunity to invite the first lady then, Mrs. Eleanor Roosevelt, to her laboratory. Initially, the first lady thought of using orphans to investigate further how the trial vaccines could work. This idea, however, did not sit well with Kendrick. Kendrick suggested a research program for a large scale trial based on the ties she has fostered with the locals of the Grand Rapids area. She hoped to find willing volunteers for her trial. The first lady spend a total of 13 hours with Kendrick that day in early 1936 and, seeing the excellent progress being made, she helped provide funding for the research.
Because of the funding which came after the first lady’s visit, Kendrick and Elderling were able to continue working on a larger scale trial in 1936. This trial later on involved more than 5,800 children from which they were able to gain positive and conclusive results. The results were indeed astounding. The children who first received the vaccine demonstrated having a stronger immune system—indicative of the positive effects of the vaccine. Follow up trials in 1938 were also successful and mass-producing the pertussis vaccine for children in Michigan began in 1938.
During that large-scale trial, Kendrick also addressed the situation concerning quarantine times. Affected children were quarantined for between two to four weeks depending on local rules. Kendrick discovered that after 5 weeks was required for more than 90 percent of affected children to be no longer infectious. Because of these findings, Michigan adapted a 35-day quarantine period.
In 1943, the vaccine which Kendrick and Elderling created was used all over the United States as a routine vaccine. In the early years of 1960, incidences of whooping cough had decreased to less than 5% compared to the rate in 1934.
Kendrick and Elderling combined three vaccines into a single shot in 1942 which fought diphtheria, pertussis, and tetanus. This is now known as the DPT shot which is now a standard vaccine nationwide. Of note is that although whooping cough incidences have been reduced all over the United States, it still continues to cause deaths in some other developing countries of the world.
Kendrick retired from her work as a member of the Michigan Department of Public Health in 1951. She then became one of the faculty members of the Department of Epidemiology at the University of Michigan, retiring in 1960. On October 8, 1980, she died at the age of 90 in the Grand Rapids.
1934 1935 field trial over 1500 children
1938 follow up trials