It’s true, polio has been eliminated in the United States.
But that doesn’t mean that we can stop vaccinating kids against polio yet.
Why Do We Still Vaccinate If Polio Has Been Eliminated?
For one thing, the last polio case in the United States was a lot more recent than 40 years ago.
What happened 40 years ago?
That was when we had the last endemic case of polio in the United States, in 1979. After that, in addition to cases of VAPP, there were at least 6 cases of imported paralytic poliomyelitis. In fact, the last case of wild polio in the United States was in 1993, just 26 years ago.
And just ten years ago, in 2009, was the very last case of VAPP, a patient with a long-standing combined immunodeficiency who was probably infected in the late 1990s, even though she didn’t develop paralysis until years later.
But still, why couldn’t we stop vaccinating against polio in the United States, even though polio isn’t eradicated yet? After all, we stopped using the smallpox vaccine in 1972, before smallpox was declared eradicated (1980).
While that is true, smallpox isn’t as contagious as polio and there hadn’t been a case of smallpox in the United States for over 30 years when we stopped using the vaccine.
Until wild polio is eradicated and the oral polio vaccine isn’t used anymore (OPV switch), we must continue to vaccinate against polio to prevent new outbreaks.
That is the polio eradication and endgame strategic plan.
Over the next few years, the world will hopefully switch to using just the injectable form of the polio vaccines, which eliminates the risk of VAPP.
But if we are so close, why not just stop vaccinating in those parts of the world that don’t have polio?
Because we are so close to eradicating polio.
Why take the risk of polio spreading from one of the remaining endemic countries, paralyzing kids, and putting eradication efforts further behind?
There is a lot more interest in polio these days, but not because we are close to eradicating this deadly disease, but rather because of the emergence of cases of acute flaccid myelitis (AFM).
Although the cases have a different cause, the symptoms of AFM are the same that we used to see during the outbreaks of polio that used to hit each summer in the pre-vaccine era.
Surprisingly, in most people, the poliovirus doesn’t actually cause any symptoms. They simply have an asymptomatic infection.
In some others, the poliovirus causes flu-like symptoms, including a fever, sore throat, nausea, and a headache – symptoms that last about 3 to 5 days.
Much more rarely, the poliovirus causes meningitis or paralysis.
It is these cases of paralytic polio that most people are aware of and that panicked parents during summers in the 1940s and 50s.
After having flu-like symptoms, those kids who would develop paralytic polio can develop pain and then flaccid paralysis.
“The most severe form, paralytic poliomyelitis, which is seen in less than 1% of patients, presents as excruciating episodes of pain in back and lower limbs. In children, the disease may present in biphasic form—a period of prodrome followed by a brief symptom-free period of 7 to 10 days and then appearance of asymmetrical paralysis of limbs. Flaccid paralysis is the hallmark with loss of deep tendon reflexes eventually.”
Mehndirattta et al on Poliomyelitis Historical Facts, Epidemiology, and Current Challenges in Eradication
Of course, polio wasn’t always called polio.
Other names have included infantile spinal paralysis, infantile paralysis, Heine-Medin disease, poliomyelitis anterior acuta, and acute anterior poliomyelitis.
The first use of the name “polio” came from Adolph Kussmaul, with his use of the term poliomyelitis anterior acuta, which was derived from the Greek polios “grey” and myelos “marrow” and itis “inflammation.” It was because he knew that it was caused by inflammation of the spinal cord gray matter, even if he didn’t know why.
Polio didn’t just suddenly appear in the middle of the 20th century though, it was likely around for ages.
In addition to an Egyptian funeral stele (a stone slab used as a monument) portraying Roma the Doorkeeper from 1500 BCE that suggests he had paralytic polio, archeologists have found evidence of polio in skeletons as far back as the Neolithic period.
Still, we don’t really know how long polio has been around and we don’t know why we began to see more cases in the mid-20th Century, although there are theories, including, ironically, about hygiene. While we often credit improved sanitation and hygiene for helping to reduce mortality from many diseases, some think that this actually set us up for polio outbreaks, as we were no longer exposed as infants, when we still had some maternal immunity.
The one thing that we do know is that we are on the verge of eradicating polio, as there are very cases now, in just a few countries.
Polio Timeline and Milestones
In addition to the more ancient discoveries about polio, there is a lot to learn about vaccines and vaccine-preventable diseases if we look at the major milestones of this important disease.
Although in the end it is a success story, the road to figuring out what caused polio symptoms and how polio could be prevented was very long.
Michael Underwood describes what is thought to be paralytic polio in his book A Treatise on the Diseases of Children, with General Directions for the Management of Infants from Birth in a section on “Debility of the Lower Extremities” (1789)
first reported outbreak of polio in Worksop, England (1835)
Jacob von Heine, head of an orthopedic hospital in Germany, publishes a monograph that describes 29 cases of paralytic polio, and actually attributes the condition to inflammation of the anterior horns of the spinal cord, although the cause was still not known (1840)
first use of the term poliomyelitis by Adolph Kussmaul (1874)
Nils August Bergenholtz reports on an outbreak of paralytic polio in Sweden (1881)
Karl-Oskar Medin, a pediatrician who reported on a polio epidemic in Sweden (1887), later presents his findings at the Tenth International Conference in Berlin (1890)
the first major outbreak in the United States is documented in Rutland County, Vermont and causes 132 cases of paralysis and 18 deaths (1894)
Ivar Wickman tracks cases of polio during an epidemic in Sweden in 1905 and was the first to suggest that polio was contagious and that you could get it from “those afflicted with the abortive type” (1907)
although they don’t actually identify the poliovirus, Dr. Karl Landsteiner and Dr. Erwin Popper identify that a virus causes polio when they inject material from the spinal cord of a child who had recently died with polio into the peritoneum of two monkeys, both of which soon developed paralytic polio (1908)
Simon Flexner, first discovers polio antibodies (1911), but unlike other researchers at the time, pushes the theory that polio was spread by the olfactory route, instead of the fecal-oral route, which was why we saw the development of nose sprays, etc., to try and prevent polio, none of which worked of course
a large polio epidemic in the United States causes at least 27,000 cases and 6,000 deaths (1916)
Philip Drinker and Louis Agassiz Shaw invent the first iron lung, the Drinker respirator (1929)
Frank M. Burnet and Jean Macnamara proposed that there were antigenically different strains of poliovirus (1931)
John R. Paul and James D. Trask help figure out how polio was spread by identifying the polio virus in human waste and sewage samples (1932)
Maurice Brodie and John Kolmer have unsuccessful field trials of early polio vaccines, including allergic reactions and vaccine induced polio because of poor attenuation (1935)
Sister Elizabeth Kenny establishes a clinic in Australia to treat polio survivors (1932) and later publishes her treatment recommendations, Infantile Paralysis and Cerebral Diplegia (1937)
the National Foundation for Infantile Paralysis is founded by FDR to stop polio (1937)
Carl Kling found traces of the poliovirus in the Stockholm sewage system (1942)
the Sister Kenny Institute is built in Minneapolis, as her treatment methods become widely accepted after years of controversy (1942)
the U.S. Army Neurotropic Virus Commission, including Albert Sabin, gets a grant from the NFIP to study polio in North Africa (1943)
Isabel Morgan actually developed the first inactivated polio vaccine, but only tested it on monkeys (1949)
John Enders, with T. H. Weller and F. C. Robbins, received the Nobel Prize in 1954 for their work on the cultivation of the poliomyelitis viruses (1949)
David Bodian creates the monkey model using field isolates of poliovirus and with Jonas Salk, identifies the three poliovirus serotyes (1950s)
Hilary Koprowki develops the first oral, live polio vaccine, (1950) although Sabin’s vaccine eventually gets licensed because it is thought to be less neurovirulent in monkeys and undergoes more testing
there are 58,000 cases of paralytic polio in the United States (1952)
Renato Dulbecco, with Marguerite Vogt, successfully grows and purifies polio virus (1952)
the Polio Pioneers vaccine field trial, led by Thomas Francis Jr., that proves that Jonas Salk’s polio vaccine is safe and effective begins (1954)
last imported case of polio in the United States (1993)
the WHO Region of the Americas is declared polio free (1994)
“last” case of VAPP that was acquired in the United States (1999)
last case of wild poliovirus type 2 (1999)
the WHO Western Pacific Region is declared polio free (2000)
the United States switches back to using the an inactivated polio vaccine because of concerns over VAPP (2000)
the WHO European Region is declared polio free (2002)
outbreak of vaccine derived polio among a group of unvaccinated Amish in Minnesota (2005)
last case of VAPP that was acquired outside the United States, an unvaccinated 22-year-old U.S. college student who became infected with polio vaccine virus while traveling in Costa Rica in a university-sponsored study-abroad program (2005)
last case of VAPP in the United States, a patient with a long-standing combined immunodeficiency who was probably infected in the late 1990s (2009)
Bob Sears says that it is okay to delay the polio vaccine on his alternative vaccine schedule because “we don’t have polio in the United States” (2015)
a global switch from trivalent OPV to bivalent OPV in routine immunization programs (2016)
polio remains endemic in just two countries, Afghanistan and Pakistan (2018)
So it should be clear, that despite what some folks think, polio wasn’t conquered overnight. And Salk and Sabin obviously had a lot of help, although those are the names we most commonly hear connected with polio eradication.
“Until poliovirus transmission is interrupted in these countries, all countries remain at risk of importation of polio, especially vulnerable countries with weak public health and immunization services and travel or trade links to endemic countries.”
Global Polio Eradication Initiative on Endemic Countries
“All members of the household should wash their hands after changing the diaper of an infant. This minimizes rotavirus transmission, for an undetermined number of weeks after vaccination, from an infant who received rotavirus vaccine.”
General Recommendations on Immunization Recommendations of the Advisory Committee on Immunization Practices (ACIP)
If you wash your hands when you change your child’s diapers after they have been vaccinated, just like you hopefully do anyway, you can avoid any possible contact with any rotavirus vaccine virus that might be shed in your child’s stool.
Can I Get Rotavirus from My Recently Vaccinated Baby?
But what would be the risk of your getting sick if you did come into contact with shedding rotavirus vaccine virus in your child’s diaper?
Would you be at risk to get sick?
Did your baby get sick after getting the actual vaccine?
That’s the thing about shedding that many people don’t understand. These live vaccines are made with attenuated or weakened strains of viruses, so they don’t typically get you sick when you are vaccinated. And they don’t typically get you sick when you are exposed through shedding. In fact, this shedding can sometimes help build herd immunity, as more people get exposed to the weakened strain of vaccine virus.
But can they get you sick?
Yes, if you have a problem with your immune system, which is why there are warnings about giving live vaccines to folks who are immunocompromised. And there used to be warnings about giving the oral polio vaccine to kids if they were around anyone with an immune system problem.
Vaccine viruses could also get you sick if they mutated from their attenuated state and became more virulent. Fortunately, that rarely happens with most vaccines.
“The theoretical risk of HRV and PRV shedding, transmission to, and infection of immunocompromised contacts is much lower than the real risk of wildtype rotavirus infection transmitted from unvaccinated children.”
Anderson on Rotavirus vaccines: viral shedding and risk of transmission
And most importantly, since kids are much more likely to shed virus after natural infections, it is much safer for everyone to get vaccinated and protected with these vaccines.
Surprisingly, even children with asymptomatic natural rotavirus infections can shed virus for several weeks, which is likely why these infections used to spread so easily or without known contacts.
Something that will likely surprise some folks even more is the news that just because someone gets diarrhea after being exposed to the rotavirus vaccine, either because they were vaccinated or through shedding, it doesn’t mean that the vaccine was the cause of the diarrhea!
“Of note, among all six AGE cases which possessed Rotarix-derived strains, four (sample No.1, 5, 6 and 7) were suspected to be caused by other pathogens. Most likely, the infants were infected with other pathogens during the shedding period of Rotarix strain.”
Kaneko et al on Identification of vaccine-derived rotavirus strains in children with acute gastroenteritis in Japan, 2012-2015
When vaccine strain rotavirus have been detected in kids with gastroenteritis, they often have other reasons to have diarrhea.
What does this all mean?
Don’t believe all of the hype anti-vaccine folks push about shedding from vaccines.
Did Modern Ventilators Replace the Iron Lung for Folks with Polio?
In addition to thinking that we just change the names of diseases when we want them to go away, some folks think that we don’t see anyone in iron lungs anymore, not because polio has been eliminated, but because modern ventilators simply replaced the iron lung.
Is that true?
The iron lung, invented in 1927, helped people with polio breath.
Unlike most of today’s ventilators, the iron lung is a negative pressure ventilator. In contrast, most modern ventilators, the ones that you see people hooked up to with a tube going down to their lungs, are positive pressure ventilators.
What’s the difference?
A positive pressure ventilator pushes air into your lungs. They are useful when you have a lung disease or simply can’t breath on your own.
When people had polio, there usually wasn’t anything wrong with their lungs – it was their chest muscles and diaphragm that were the problem. So the negative pressure in the iron lung would compress and decompress their chest.
One benefit of the iron lung included that it was less invasive than ventilating someone through a tracheostomy, which became an option in the 1960s. While many new options became available for those needing long term ventilation since then, including noninvasive positive pressure ventilation, some still like to use their iron lungs.
And while it is true that they don’t make them anymore, iron lungs have not disappeared. There are some folks with polio that still use them.
But what if someone developed polio now, would they be put in an iron lung?
No, they wouldn’t. For one thing, they don’t make iron lungs anymore. Instead, they would likely use mouth intermittent positive pressure ventilation.
Still, we don’t see a lot of folks getting diagnosed with polio, needing to use mouth intermittent positive pressure ventilation, instead of iron lungs these days. And that’s because we don’t see a lot of folks getting diagnosed with polio.
What to Know About Polio, Modern Ventilators and Iron Lungs
Although some people with polio are still using their iron lungs, the main reason we don’t see more people with polio needing to use iron lungs or modern ventilators is simply because polio is almost eradicated.