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Ebola & Quarantines: The Importance of Solid Critical Thinking

Friday, October 31, 2014

A little less than a hundred years ago, the song of the crickets in the evening was joined by the banter of four women playing bridge well into the night.  The ladies retired a bit after 11pm.

By the next morning three were dead.

Medical lore from the time tells of a man boarding a cable car feeling well enough to head off to work.  He was dead six blocks later. By the end of that winter, worldwide two billion people would contract what became known as the 'Spanish Flu'.  Between 20 and 40 million of them would die from it.

We are hearing from government - and the refrain is being repeated by the media - that a person who has Ebola is only infectious when they are showing symptoms.  We are also being told that Ebola is only transmitted by direct contact with bodily fluids.  I will not challenge either the science (virology and epidemiology) or the medicine (protocols for treating Ebola).  I will, though, question the quality of thinking which is coming not only from the media, but from government officials with scientific and medical training who should know better.

Let's start here: The science tells us that a person with Ebola is only 'infectious' when they start showing symptoms, and then the virus can only be transmitted by direct contact with bodily fluids.  Taking these two things up one by one:
Ebola is only infectious when a carrier is showing symptoms - until a new strain proves to be infectious before then; and...
Ebola can only be transmitted by direct contact with bodily fluids - until a new strain proves to be more easily transmitted.
The history of the Spanish Flu outbreak of 1918 should caution us against missing some important things about the nature of scientific inquiry itself.  To start with, science does not traffic in the kind of 'certainties' that mark today's pronouncements on Ebola.  Science is always aware of the possibility that new observations will challenge old dogmas.  If there is any field where this caution should be observed, it has to be the field of infectious diseases (epidemiology) - which must account for the manner in which viruses mutate.

And so we come to the controversy over quarantining health workers returning from West Africa.  Here we have to start with a basic question about public policy: Do we base public policy only on what we know?  Or do we base public policy on what we do not know?

If we are talking about a pathogen like influenza, we see a mortality rate of 0.1%, and thus it makes sense to base public policy on what we know.  But even then, we face the risk that a new strain can devastate a population as happened in 1918.  But when we are talking about a pathogen like Ebola with a historic mortality rate between 25-90 percent, prudence would seem to dictate that public policy be oriented to what we do not know.

So let's review: We do know that viruses mutate.  We do not know what the next strain of Ebola will look like.  We do not know whether or not an asymptomatic person will be infectious when the next strain emerges.  We do not know whether the next strain will be more easily transmitted than the strain we know of today.  And thus we have no idea what treatment protocols will have to look like for the next strain.  But to repeat: We do know that viruses mutate.

This, then, brings us to the matter of health workers returning from West Africa.  If one were to carry the virus, we do not know whether they will carry the currently known strain or a new strain.  Or to put it another way - we do not know whether they might be 'Patient Zero' for the next strain of Ebola.

So consider the public policy choices available: If we base public policy only on what we know, there is no reason to quarantine a health worker who is asymptomatic.  If, however, the mortality rate of Ebola cautions us to base public policy on what we do not know, we might choose to enforce a 21 day quarantine.  If the returning health worker does carry a new strain, we will discover this without the tragic consequences of allowing what we do not know to spread unabated.

Or can we go merrily on our way under the false impression that what is known about Ebola today is known for 'certain' such that we would not entertain concerns about what might develop should the virus mutate.  If we do this, a potential 'Patient Zero' can be out and about society unknowingly spreading the next strain.

We need better thinking from government - and from media as well.

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