Jonas Salk & the Polio Vaccine

Instructor: Julie Zundel

Julie has taught high school Zoology, Biology, Physical Science and Chem Tech. She has a Bachelor of Science in Biology and a Master of Education.

When you go to the doctor for a shot, you probably don't think about immunity, or the work that went into the development of the vaccine. This lesson will discuss Jonas Salk and his work in developing the polio vaccine.

The Polio Problem

Usually a sore throat, fever, stomachache, and nausea will go away after a few days of rest, but with poliomyelitis (or polio for short), these symptoms can turn into something far more serious. Polio is caused by the poliovirus, and it can lead to an array of medical problems.

While around 72% of the people who contract polio won't have any symptoms, some will have the flu-like symptoms mentioned earlier, whereas others will have spinal cord and brain involvement that can result in permanent paralysis and death. Polio can impact any age group; however, children are the most impacted and are often left with debilitating, crippling effects.

Man who was crippled from polio

Polio is easily transmitted, and it crippled thousands during the 1940s and 1950s. In 1952, the worst year of the epidemic, there were 58,000 cases of polio that were reported in the United States. Out of that 58,000, 3,145 people died and 21,269 people were crippled. Fortunately, a vaccine developed by Jonas Salk, a scientist who studied viruses in the 20th century, reduced polio outbreaks. The United States has been polio free since 1979. Let's take a closer look at Jonas Salk and the race to develop a polio vaccine.

While polio impacted mostly children, Franklin D. Roosevelt contracted the disease as an adult, and it left him crippled.

Jonas Salk and the Development of the Vaccine

Normally, when you think of scientists developing vaccinations and cures for diseases, you might imagine a sterile hospital and scientific trials. But Jonas Salk took a somewhat unorthodox approach. In the early 1950s, after testing the vaccine on monkeys, Salk sterilized some syringes by boiling them in water on his stove and injected himself, his wife and his three children with the polio vaccine. Of course Salk did work in a lab setting, and did perform vaccine trials (more on that later), but the path to the vaccine did literally go through his family.

Another unorthodox move by Salk was the way the vaccine was developed. Prior to this vaccine, most vaccines were developed from live viruses; yet Salk created the polio vaccine by growing the virus and then killing it with formaldehyde. The killed virus was injected into humans, and then the immune system developed antibodies. This prevented anyone from actually getting sick from the vaccine, while still providing people with immunity, or protection, from polio.

Albert Sabin, another scientist, believed Salk's approach to the polio vaccine was flawed. He believed lasting protection from polio could only be obtained by using a live virus in the vaccination. In the race to develop the vaccine, mistakes were made. For example, in 1955 several children died due to a bad batch of vaccinations.

Eventually Sabin developed a vaccine with live polio, and this vaccine replaced Salk's from 1963 to 1999. Since Sabin's vaccine is live, it can (in some instances) cause polio, so today, the United States has returned to utilizing Salk's killed vaccine.

The development of a vaccine was front page news.

Let's learn a little more about the early life of Salk and how he came to be one of the most influential scientists of the 20th century.

Salk: Road to the Vaccine

Jonas Salk was born in New York in 1941. While his parents did not have much money, they emphasized the importance of education. Salk graduated from the College of New York and in 1939 received his medical degree from New York University. He began studying viruses during his internship at the University of Michigan.

Later, in 1947, Salk worked at the University of Pittsburgh, where he studied polio and became the head of the Virus Research Lab. Salk learned that the 125 strains of polio could be divided into three different categories. As he worked to make a vaccine, he realized that whatever he developed would need to protect the body from all of the different strains of polio.

One of the challenges Salk faced was growing enough of the poliovirus to experiment with. Fortunately for Salk, researchers at Harvard found a way to grow a lot of poliovirus on body tissues. This helped with his research, and in 1952 he developed a vaccine, which he tested on monkeys and children who had survived and recovered from polio. This trial expanded to those who did not have polio (including himself, his wife and his children).

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