Milestones in Pharmaceutical History: Living Legacies of the Polio Vaccine

October is American Pharmacists Month – time to recognize pharmacists’ contributions to health care and all they do for their communities. In their honor, we’re publishing a series of posts this month about milestones in pharmaceutical history that have immeasurably advanced drug safety and improved public health. In this post, we applaud the achievements of Jonas Salk and Henrietta Lacks, whose unusual “partnership” resulted in the polio vaccine that has saved an untold number of lives since its introduction in 1955.

Research & Development

Until Jonas Salk introduced his vaccine, polio was perceived as one of the world’s most worrisome public health problems. As recently as 1952, the U.S. suffered its worst outbreak in history: 58,000 cases were reported; 3,145 victims died and 21,269 were left with mild to disabling paralysis – most of them children. Given this state of emergency, scientists were frantically racing to discover a cure or method to prevent the disease. 

In 1948, Jonas Salk, an American medical researcher and virologist, undertook a project funded by the National Foundation for Infantile Paralysis to determine the number of different types of poliovirus. Salk viewed this project as a chance to extend his research towards developing an injectable vaccine. Together with his skilled team at the University of Pittsburgh School of Medicine, he devoted the next seven years to this mission.

To test the vaccine, Salk set up the most elaborate field trial of its kind in history. It involved 20,000 physicians and public health officers, 64,000 school personnel, and 220,000 volunteers. More than1,800,000 school children also took part in the trial, which delivered spectacular results at the trial’s conclusion.

Jonas Salk’s Global Achievement

When the vaccine’s success was made public on April 12, 1955, Salk was hailed as a “miracle worker” and the date was celebrated, not unlike a national holiday. Salk responded that public health should be considered a “moral commitment” and that his only focus was on developing a safe and effective vaccine as rapidly as possible. He had no interest in personal profit, and to this day, no patent exists for his injectable vaccination method.

Soon after the vaccine was licensed, Salk campaigned vigorously for mandatary children’s vaccination programs, which were launched immediately around the world. In the U.S. alone, following a program promoted by the March of Dimes, the annual number of polio cases fell 84%, from 35,000 in 1953 to 5,600 in 1957.

During this time, fellow virologist Albert Sabin worked on developing an oral vaccine. Once it was on the commercial market in 1961, his oral method eventually supplanted Salk’s injection method, and total U.S. cases of polio dropped to 161. Both the injectable and oral vaccines are currently on the World Health Organization's List of Essential Medicines.

In 1988, the World Health Organization joined forces with UNICEF and The Rotary Foundation to lead a global effort to eradicate polio, achieving massive success:

• 1994: Polio was eliminated in North and South America.
• 2000: The disease was officially eradicated in 36 Western Pacific countries, including China and Australia.
• 2002: Europe was declared polio-free.
• 2014: India was also declared polio-free.

In total, the number of cases reported worldwide each year dropped from an estimated 350,000 in 1988 to merely 22 in 2017.

The Legacy of Henrietta Lacks (HeLa)

An interesting yet little-known chapter of the polio vaccine story is the unsung contribution of cancer patient Henrietta Lacks to its development. When Salk was testing his vaccine, he significantly expedited the process by taking advantage of the first immortalized cell line available to researchers. These extraordinary human cells, grown in a lab, do not die no matter how many times they are divided for testing purposes. They can then be used indefinitely for a multitude of medical experiments. Salk and generations of researchers after him, therefore, owe a great deal to Henrietta Lacks, whose immortal cells remain both the first and the oldest line still in use today.

Cell biologist George Gey discovered that cells taken from Henrietta’s cervix could be kept alive indefinitely by isolating one specific cell and multiplying it into a durable and prolific cell that could be used extensively in scientific research. Previously, stocks of living cells were limited, required significant effort to culture, and survived for a few days at most. Scientists spent more time trying to keep the cells alive than performing actual research with them.

As was Gey's custom, he labeled the culture “HeLa” from a combination of the first two letters of the patients first and last name. Astonishingly, although she died of cancer in 1951, Henrietta Lack continues to live on as HeLa. Her immortal cell line has led to many important breakthroughs in biomedical research and has saved and extended the lives of many others, including our current generation, free from the worry of contracting polio.

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