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On the odd parallels between poliovirus and SARS-COV-2

2020-05-21

photo by AtlantaMomoFive courtesy of pixabay.com

Franklin Delano Roosevelt (the president we need now) was a famous sufferer of paralytic poliomyelitis.  He lost the ability to walk and spent years recuperating.  He was an adult when he came down with the disease, unlike the average patient, who is usually under five years of age.  He also took up stamp collecting because of his illness… but that’s another story.

There are some odd, little known parallels between poliovirus and the novel coronavirus– Sars-CoV-2 (which causes CoViD-19)– parallels with which I was unaware until I looked up the symptoms of polio while watching the movie about Sister Kenny, an Australian nurse who revolutionized the treatment of polio before and after WW I.  First, polio is “defined” as “paralytic poliomyelitis”, which excludes asymptomatic and nonparalytic infections with the poliovirus.  Second, polio infection is actually asymptomatic in most cases.  If I remember correctly after perusing the various sources available to Google on my phone while watching the movie (OK, not the best way to retain the information, I grant): only about 0.5 percent of polio cases involve weakness or paralysis.

Most commonly, polio weakness affects the legs, but then it can also affect the head, neck, and diaphragm.   “In those with muscle weakness, about 2 to 5 percent of children and 15 to 30 percent of adults die” (based on an authoritative textbook, as quoted from Wikipedia).  Some 70 to 75 percent of people with polio infection have no symptoms; most of the rest have “minor” effects such as fever, chills, sore throat; “up to 5 percent have headache, neck stiffness and pains in the arms and legs.”

Thus, the picture presented in the movie of children moaning with pain and having stiffness is accurate; most of these patients will recover fully within two weeks.  Again, only half of one percent of infected patients (say, ten percent of those with headache, stiffness, and pain) will go on to develop weakness or paralysis.  One of the more lately realized effects of polio is called “post-polio syndrome” in which patients with stable weakness develop additional problems many years later (5 to 20 or more years).  These patients will have increasing weakness in the same areas as before, with spreading of the weakness and concomitant fatigue and depression.

Parenthetically, my father suffered from polio when he was about 18; he was left with a withered calf and later developed osteoporosis in the affected lower leg.  He tried to hide the condition but no longer was able to participate in vigorous sports.  Previously, he had gained his high school diploma by playing tight end on a football team in Texas for one season (this was despite never having attended high school).  He had also participated in professional boxing at a low level as a teenager.  This was one reason why he never played catch with me or taught me to bat.

Anyway, to the comparison with the novel coronavirus: as you should know by now, it appears that many cases of this virus are asymptomatic.  The exact percentage is not yet known, but may be between 25 and 50 percent, or more– we just don’t know.  The milder manifestations of the new virus are also similar: fever, headache, sore throat.  Here the differences begin: polio doesn’t appear to ever cause a cough.  Polio apparently can cause diarrhea, abdominal pain, nausea, and vomiting, although this is not prominent.  The new virus can sometimes cause gastrointestinal symptoms as well.

Transmission of polio is primarily by the fecal-oral route, that is, the virus is passed in stool and infects others through contamination of water supplies.  The new virus is also passed in stool, but this doesn’t appear to be a primary method of transmission, perhaps because sanitation is so much better now than it was in the heyday of polio.  The new virus is primarily passed from person to person by breathing in the oral/tracheal secretions of others, passed in the air through coughing and even talking or just breathing.  The new virus survives on surfaces for a time and can be passed in this way, although I doubt if this is a major route if everyone washes their hands and refrains from touching their faces every five minutes (I’m joking, ok?)

So here we have two viral infections that are or were epidemic; both are primarily asymptomatic (although this was not known in years past), making it appear that paralytic polio was a rare disease.  The harmful effects of polio are well known, and the stereotype is that of an affected person left with permanent paralysis and a withered leg or surviving in an “iron lung”.  I wonder how long it will be before we see persons affected by severe coronavirus living in iron lungs for a  month or more… a while, because there just aren’t too many iron lungs available.  In all this work at building makeshift ventilators, I have not seen anyone just go back to the old iron lungs; perhaps they don’t remember.

That’s enough about polio.  Except that there are two excellent vaccines available, one a killed/inactivated virus, the other a mutated live virus.  The live virus vaccine is used in developing countries where the incidence of polio is higher and sanitary water facilities are hard to come by.  The advantage of the live virus vaccine is that it spreads through the same route as the wild virus and thus can afford protection to people who drink contaminated water and are thus exposed.  The disadvantage is that sometimes the virus mutates back to a more harmful form and then causes the same disease it was designed to protect against.  Polio is so rare in this country (the US) that the mutation event is considered more harmful, and more common, than exposure to the wild virus– thus it is safer to give the killed virus vaccine despite its weaker protection levels.

As yet there is no vaccine available against the novel coronavirus.  That will change, probably in less than a year.  There was opposition to the polio vaccine, too, but it has been forgotten– I don’t think the opposition to the CoViD vaccine will be forgotten.

 

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