The Polio Vaccine, Part 1: The Injected Vaccine Verses the Oral Vaccine

The Tale of Two Polio Vaccines

In the 1940's and 50's, two men began work on competing Polio vaccines, both operating under different philosophies on how the body develops immunity.

Jonas Salk, credited with discovering the Polio vaccine, believed in using a killed virus, which would have no chance of accidentally spreading the disease. His vaccine was injected into a muscle, typically in the arm. 

Albert Sabin believed that the body could not recognize a killed virus the same way as a live one and would not develop a lasting immunity. He also believed that a Polio vaccine would need to enter the body the same way as the regular, live virus - that is, through the mouth, to enter into the intestines. His version of the Polio vaccine was administered orally and contained attenuated, or inactivated, viruses.

Neither scientist patented their vaccine, but instead chose to donate their discoveries to the benefit of humanity.

Jonas Salk's Killed Virus Polio Vaccine

In 1952, Salk's polio vaccine was tested. Having been developed using three different viruses cultured in monkey kidneys and killed in formalin (formaldehyde). A successful trial led to a larger scale study in 1954 involving children in the United States and Canada. Salk's vaccine was deemed a success and the Polio vaccine was approved for mass distribution.

The problem was that not all of the viruses were effectively killed. Several hundred children became infected with Polio, and several children died.

"Of course, the Salk vaccine was tested before release. It was tested on nearly 2 million children in 44 States. A Dr. Thomas Francis Jr., director of the Poliomyelitis Evaluation Centre at the University of Michigan, analysed the results of Dr. Salk's experiments. On April 12th 1955 at Ann Arbor, Michigan, in front of a meeting of 500 selected public health doctors and polio experts, and distributed by television to another 54,000 doctors in the U.S. and Canada, he declared the vaccine safe, powerful and effective...

Yet, some contemporary scientists uttered their concern about the report.