VACCINE VISIONARIES

		Image has been reproduced from Famous Scientists
	JONAS SALK: PROTECTION FROM POLIO

Jonas Salk was like Chaucer’s Clerk of Oxenford—eager to learn and share what he knew. For him knowledge was to be disseminated. It is interesting to note his response when he was asked in 1955 after discovering the polio vaccine: "Who owns the patent on this vaccine?" He responded: "There is no patent. Could you patent the sun?

Though the polio virus was discovered in 1908 by Austrian physicians Karl Landsteiner and E. Popper, it was only in the mid-1950s that the vaccine was identified. In fact, polio as a disease is traced back to Egyptian times (16th-13th centuries B.C.). A stone slab depicts a priest leaning on a staff with his right leg withered and dangling in the equinus position—a typical sign of polio. The virus survived into the middle of the 20th century, and in 1952 almost 52,000 cases of polio were reported in the United States. It was a disease that instilled fear because there was no immediate cure and survivors were left crippled for life.

Research for a polio vaccine had begun in the 1930s and now America invested all its post-war resources into finding a solution. At this point in time, Jonas Salk was working at the Pittsburgh University, where he had been on the faculty since 1947 as assistant professor of bacteriology. He had been researching on a vaccine for polio and a breakthrough was imminent.

Brochures that were distributed before the polio vaccine was discovered

What aided him was the discovery in 1949 that there were three distinct types of polio viruses. With a grant from the National Foundation for Infantile Paralysis, Salk employed the newly discovered tissue-culture method to prepare a killed-virus vaccine effective against all the three types. Testing began in 1950, and a report on the vaccine's effectiveness was published in the Journal of the American Medical Association in 1953.  National field trials were conducted in 1954, and in 1955 the vaccine was declared safe for use in mass immunization. But by 1962 the Salk vaccine was replaced by the Sabin oral vaccine.

Take a polio quiz

• What are the three types of polio virus?

• What was Jonas Salk researching on before he discovered the polio vaccine?

• How is the Sabin vaccine different from the Salk vaccine?

• Can you mention a precursor to Band Aid and other such programmes that served to create polio awareness among the public?

• Who was the US president afflicted by polio?

• Which are the three countries where polio outbreak has been reported in recent times?

• Which was the only country that continued to use the Salk vaccine even after the Sabin vaccine was adopted worldwide?

• Who first discovered poliomyelitis as a distinct condition?