The Myth That Polio Only Went Away Because They Changed the Way It Was Diagnosed

Have you heard this one?

“Before the vaccine was developed, the diagnosis of polio required 24 or more hours of paralysis. After the vaccine release, the diagnosis changed to at least 60 days of paralysis. As you can imagine, cases of polio dropped significantly.”

So that’s why polio went away?

It wasn’t the vaccine?

The Myth That Polio Went Away Because They Changed the Diagnostic Criteria

In 1952, there were 21,000 cases of paralytic polio in the United States.

But were there really?

Didn’t they change the way they diagnosed polio a few years later, right after the first polio vaccines came out, making it less likely that folks would be diagnosed with polio?

The original diagnostic criteria for polio came from the World Health Organization and included:

“Signs and symptoms of nonparalytic poliomyelitis with the addition of partial or complete paralysis of one or more muscle groups, detected on two examinations at least 24 hours apart.”

It changed in 1955 to include residual paralysis 10 to 20 days after onset of illness and again 50 to 70 days after onset.


“In the past children’s paralysis was often not correctly diagnosed as polio. Stool samples need to be analyzed to be able to distinguish paralytic symptoms from Guillain-Barré Syndrome, transverse myelitis, or traumatic neuritis.”

Polio – Data Quality and Measurement

But you coulld’t just use stool samples, as many kids might have recently had non-paralytic polio, and could test positive for polio (false positive test), but have another reason to have paralysis.

“Isolation of poliovirus is helpful but not necessary to confirm a case of paralytic poliomyelitis, and isolation of poliovirus itself does not confirm diagnosis.”

Alexander et al. on Vaccine Policy Changes and Epidemiology of Poliomyelitis in the United States

Since polio causes residual paralysis, the new diagnostic criteria helped to make sure that kids were diagnosed correctly.

Did We Overestimate the Number of Kids with Polio?

Some folks think that since we changed the criteria, we overestimated the number of kids with polio in the years before the vaccine came out.

Most of this idea seems to come from a panel discussion in 1960 by critics of the original polio vaccine, The Present Status of Polio Vaccines, including two, Dr. Herald R. Cox and Dr. Herman Kleinman, who were working on a competing live-virus vaccine.

None in the group were arguing against vaccines, or even really, that the Salk polio vaccine didn’t work at all though. They just didn’t think that it was effective as some folks thought.

“I’ve talked long enough. The only other thing I can say is that the live poliovirus vaccine is coming. It takes time. The one thing I am sure of in this life is that the truth always wins out.”

Dr. Herald R. Cox on The Present Status of Polio Vaccines

Dr. Cox did talk a lot about the oral polio vaccine. He talked about successful trials in Minneapolis, Nicaragua, Finland, West Germany, France, Spain, Canada, Japan, and Costa Rica, etc.

When anti-vaccine folks cherry pick quotes from The Present Status of Polio Vaccines discussion panel, they seem to leave out all of the stuff about how well the oral polio vaccine works.

That’s how they work to scare parents and hope that their anti-vaccine myths and misinformation can win out over the truth that vaccines work and that they are safe and necessary.

“Since nothing is available, there seems to be no alternative but to push the use of it. I don’t think we should do so in ignorance, nor too complacently, believing that as long as we have something partially effective there is no need to have something better.”

Dr. Bernard Greenberg on The Present Status of Polio Vaccines

And of course, they did, fairly soon, switch to something better – the Sabin live-virus oral polio vaccine.

Interestingly, using the idea that we changed the diagnostic criteria to make polio go away in an argument about vaccines is known as the Greenberg Gambit.

It tells you something about anti-vaccine arguments, that these folks are misinterpreting something someone said about vaccines almost 60 years ago.

In pushing the idea that polio hasn’t been eliminated, but rather just redefined, they also miss that:

But isn’t polio still around and just renamed as transverse myelitis, Guillain-Barré syndrome (GBS), and aseptic meningitis?

Let’s do the math.

Using the adjusted numbers in the The Present Status of Polio Vaccines discussion, there were at about 6,000 cases of paralytic polio in the United States in 1959.

While 3,000 to 6,000 people in the United States develop Guillain-Barré syndrome each year, the risk increases with age, and it is rare in young kids. Remember, paralytic polio mostly affected younger children, typically those under age 5 years.

“Transverse myelitis can affect people of any age, gender, or race. It does not appear to be genetic or run in families. A peak in incidence rates (the number of new cases per year) appears to occur between 10 and 19 years and 30 and 39 years.”

Transverse Myelitis Fact Sheet

Similarly, transverse myelitis is uncommon in younger children, and there are even fewer cases, about 1,400 a year.

What about aseptic meningitis? That doesn’t usually cause paralysis.

So do the math.

You aren’t going to find that many kids (remember, the incidence was 5-7 per 1,000) under age 5 years who really have “polio,” but instead, because of a worldwide conspiracy about vaccines, are getting diagnosed with transverse myelitis, Guillain-Barré syndrome (GBS), or aseptic meningitis instead.

Anyway, kids with acute flaccid paralysis are thoroughly tested to make sure they don’t have polio. And both transverse myelitis and Guillain-Barré syndrome have different signs and symptoms from paralytic polio. Unlike polio, which as asymmetric muscle atrophy, the atrophy in transverse myelitis and Guillain-Barré syndrome is symmetrical. Also, unlike those other conditions that cause AFP, with polio, nerve conduction velocity tests and electromyography testing will be abnormal. Plus, polio typically starts with a fever. The other conditions don’t.  So while these conditions might all be included in a differential diagnosis for someone with AFP, they are not usually that hard to distinguish.

“Each case of AFP should be followed by a diagnosis to find its cause. Within 14 days of the onset of AFP two stool samples should be collected 24 to 48 hours apart and need to be sent to a GPEI accredited laboratory to be tested for the poliovirus.”

Polio – Data Quality and Measurement

But why be so strict on following up on every case of AFP?

It’s very simple.

If you miss a case of polio, then it could lead to many more cases of polio. And that would tmake it very hard to eradicate polio in an area.

If anything, until the establishment of the Global Polio Eradication Initiative (GPEI) in 1988, it is thought that cases of polio and paralytic polio were greatly underestimated in many parts of the world!

And now polio is almost eradicated.

“DR. SABIN: Let us agree, at least, that things are not being brushed aside. Let us say that we might disagree on the extent to which certain things have received study. But I hope that Dr. Bodian realizes that nobody is brushing things aside. I would not have taken the trouble of spending several months studying viremia with different strains in chimpanzees and human volunteers, and viremia produced by certain low temperature mutants to correlate it with their invasive capacity, if I were merely brushing it aside.”

Live Polio Vaccines – Papers Presented and Discussions Held at the First International Conference on Live Poliovirus Vaccines

There is no conspiracy.

Think about it.

If they redefined how paralytic polio was diagnosed in 1955 as part of a conspiracy to make it look like the polio vaccines were working, then why did the number of cases continue to drop into the 1960s?

Shouldn’t they have just dropped in 1955 and then stayed at the same lower level?

After the switch to the Sabin vaccine, polio was on its way to being eliminated in the United States.
After the switch to the Sabin vaccine, polio was on its way to being eliminated in the United States, although there was an uptick in 1959, before we made the switch.

And why don’t any of the folks with other conditions that cause paralysis, like transverse myelitis and Guillain-Barré syndrome (GBS) ever have polio virus in their system when they are tested?

Also, if the renaming theory explains why the polio vaccine didn’t work, then why do anti-vaccine folks also need to push misinformation about DDT and polio?

What to Know About Polio Myths and Conspiracies

The near eradication of polio from the world is one of the big success stories of the modern era, just as those who push the idea that has all been faked is a snapshot of society at one of our low points.

More on Polio Myths and Conspiracies

4 thoughts on “The Myth That Polio Only Went Away Because They Changed the Way It Was Diagnosed

  1. So it’s true then, the definition did change. There is a glaring omission on this page, the world wide occurrences of NPAFP, Non Polio Acute Flaccid Paralysis in developing countries such as India


  2. You asked but didn’t actually answer the question, “Did We Overestimate the Number of Kids with Polio?” You just did a bait and switch and went off in another direction.


  3. This article would be much more convincing if you showed annual 100 year history of poliomyelitis incidence, next to the 100 year history of transverse myelitis incidence, next to the 100 year history of Guillian Barre incidence, next to the 100 year history of acute flaccid paralysis incidence. If poliomyelitis cases decreased (as they were before the vaccine) while the other diagnoses increase in incidence, this would blow up your whole argument. Any reason this data was omitted from this article?


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