A Science Odyssey 'On The Edge'

Paralyzing Polio


Narrative: Polio, that evil disease which threatens to steal the limbs and lungs of children and adults everywhere, is on the verge of being eradicated, thanks to the work of Dr. Jonas Salk of the University of Pittsburgh, who has just announced the development of his new vaccine. We join mild-mannered Clark Klint and the Chief as they discuss the vaccine...

Chief: Klint, this polio vaccine story is going to be big! I want you to get on it right away. Get some background -- you know, a story that'll turn on the waterworks, then go talk to this Jonas Salk character.

Clark: But Chief --

Chief: And bring that goof-ball Nolson with you!

Clark: Right away, Chief.

Narrative: Later that day...

Kid in iron lung: ...and that's when I was put in this iron lung. Without it, I wouldn't be able to breathe. You see, when air is pumped out of the iron lung, the air pressure outside the lung is greater than the pressure inside. And the higher outside pressure forces air into my lungs.

Clark: That's tough, kid. How long will you have to stay in there?

Kid: I dunno. Until I can breath again on my own. It can take a few months.

Jimmy: Gee whiz, Mr. Klint, seeing all of these kids with polio sure is depressing.

Clark: Yes, Jimmy. But tomorrow we'll meet the man who may put an end to all of this senseless hardship and misery -- Dr. Jonas Salk.

Narrative: The next day, at the University of Pittsburgh...

Clark: So, Dr. Salk, your vaccine is ready for the public.

Dr. Salk: That's right, Mr. Klint. I've tested the vaccine over the past two years and I am confident that it is safe and effective against all three strains of the poliomyelitis virus.

Jimmy: Gosh, Dr. Salk, it sure seems like a miracle that the stuff in that needle could keep someone from getting polio.

Dr. Salk: This "stuff" actually contains the polio virus.

Jimmy: Holy smokes! You're putting a virus into that girl!

Dr. Salk: Yes, but the viruses within the liquid are dead. Let me explain. For most of the 20th century, we've known that the body's main defense against infection by viruses and bacteria are antibodies.

Dr. Salk: Antibodies are like little soldiers in your body, fighting to keep you healthy. They attach themselves to invading viruses and bacteria, or "antigens," thus disabling the antigen.

But an antibody is only effective against the type of antigen it was created to fight. For example, a smallpox antibody is effective only against a smallpox virus. And your body doesn't have an antibody for every type of antigen that enters it.

If a new type of antigen enters the body, an antibody made specifically to fight that antigen is manufactured. If, at some later time, the same antigen enters the body, the antibody will attack and disable it.

Dr. Salk: So you see, the dead polio viruses I am injecting into this young girl's bloodstream will cause her body to create antibodies against polio. Then, if a live polio virus ever enters her body, she'll have the antibodies to fight it off.

Clark: I see. So without the anti-polio antibodies, the virus would multiply and spread throughout the body.

Dr. Salk: That's right. The virus makes its way to nerve cells of the central nervous system, where they multiply so quickly that the cell is damaged or destroyed. This is how polio causes paralysis.

Jimmy: Holy smokes, Mr. Klint! We've got a plane to catch!

Clark: Gosh, Flois, this story sure is a complex one. On one hand there's Jonas Salk, the guy who developed the polio vaccine.

Flois: He's been getting a lot of press lately.

Clark: Then I find out that there are these three guys from Boston: John Enders, Thomas Weller, and Frederick Robbins. They came up with a way to grow viruses in human tissue. This technique was critical to the development of a vaccine.

Flois: Sounds important.

Clark: And there's this other guy, Dr. Albert Sabin. He's been working on a polio vaccine for years. If he's successful, his vaccine will work differently than Salk's. I'm off to interview him next.

Flois: Good luck.

Narrative: The next day, at the University of Cincinnati Medical School...

Dr. Sabin: Yes, Mr. Klint, my vaccine is quite different from the Salk vaccine. You see, Salk's vaccine consists of dead polio viruses.

Mine will consist of live viruses -- a strain of the virus I found that does not produce the disease, but does cause the body to produce antibodies.

Jimmy: Gosh, sir, I sure wouldn't like to have live polio viruses injected into my body.

Dr. Sabin: I assure you that the vaccine is safe, although proponents of Salk's killed vaccine would argue that point. Truth is, there's no conclusive proof that one is safer than the other.

Clark: So then what's the difference between the two?

Dr. Sabin: Well, one difference is in how it's administered. The killed virus vaccine is injected into the bloodstream. You'll also need booster shots periodically.

Dr. Sabin: My live virus vaccine is taken orally -- you just swallow it. The virus ends up in the intestines, where it multiplies and enters the bloodstream. Your body then produces antibodies.

Jimmy: Holy smokes!

Dr. Sabin: Another benefit of the oral vaccine: it lasts longer. There's no need for a booster.

Chief: Great story! To think that kids no longer need to worry about polio and spending a life on crutches. I told you this story would be big! Good work, Klint!

Clark: Gee, thanks, Chief.

An Update on Polio Vaccines

Jonas Salk's vaccine saw widespread use in 1954. Two years later, Albert Sabin's vaccine came into use. By 1959, about fifteen million citizens of the Soviet Union had received Sabin's vaccine. The vaccine was approved for use in the United States in 1961 and has since become the standard.


Related People and Discoveries entries

graphic version of Paralyzing Polio

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