Every month I go over New England Journal of Medicine Articles with a group of colleagues who range from internists to orthopedists to oncologists in a hospital based journal club.
They are a bright group, brighter than me, who have great command of statistical analysis and who bring rigorous thought to examining the flaws in studies which often look pretty good to me until they begin to dissect them out.
But tonight they asked me to summarize what I hear from "This Week in Virology," since I'm the only one in the group who listens religiously to all 4 hours of TWiV every week.
And then things went south in a hurry.
One, a doctor who has traveled the world extensively, asserted that SARS COV-2 had originated in the wet markets of China, which he has seen, where bats are kept in cages, which provoked another to assert that the virus came out of the Wuhan laboratory, neighboring the wet market, where it was made and the Wuhan facility had to be shut down because all the lab folks there died and that American scientists had be withdrawn from that facility years ago because it was so sloppy. * Another said the dose of inoculation of SARS COVID 2 is what's important and that's why the New York City outbreak was so bad, because of the subways. Another said that once you have had COVID 19 if you are exposed again, you'll have a milder version, so herd immunity will be the answer.
Of course, all these things have been repeatedly and meticulously addressed by the virologists and immunologists on TWiV.
So here's what I remember from TWiV--
I have no journal articles to refer to, although I suppose I could comb back through the "bullet points" on the TWiV website, but here's just from memory:
1. SARS COV-2 AS A CHINESE PLOT:
This virus was not manufactured in the Wuhan laboratory. As every virologist has said, no virologist or group of virologist is smart enough or capable of creating such a virus.
Conspiracy rants that the Wuhan lab was shut down when all the workers died or that it was the source of SARS COV-2 have been a Breibart horror movie tale, but now even otherwise erudite physicians are picking this up in their politically groomed nasal hairs and it's getting transmitted to their brains and broadcast to unsuspecting colleagues.
Some version of SARS COV-2 may have been circulating in bats for some time, years even, before it "spilled over" into human beings.
Even before the wet market event, cases of COVID 19 had been described.
Bats pooping on pig feed on farms may be as much a problem as wet markets, so the idea you can simply close the wet markets to prevent the next epidemic is wishful thinking. Wet markets are so repugnant to Western eyes, it's easy to believe they would be a source of pestilence and they may well be, but they may not be the source of this particular outbreak and to say so is to leap from an emotional reaction to a conclusion which needs to be proven with actual science.
This would be an easy solution--"just" close the wet markets, when what is really needed is in the field sampling world wide, which would cost money and substantial effort over years to maintain surveillance over emerging viruses, and no government official wants to even think about paying a bunch of virologist hunters to do this.
2. THE DOSE OF INOCULUM:
This is a concept which goes back to medical school. It stands to reason, if you get a whopping big dose of millions of living viruses directed into your nose and throat you'd be a lot more likely to get sick unto death than if you got just a few. In fact, the initial experience in New York was that doctors who intubated patients in the ICU were much more likely to get seriously ill seemed to suggest this inoculum effect. But Vincent Racaniello has repeatedly said he's seen no persuasive articles to support this. It's almost impossible to know what the "dose of inoculum" was in any given case.
The fact is, the patient who gets a small dose, with the wrong immune system may be overwhelmed by the rapidly reproducing virus which can generate millions of particles over just a few days, so whether you start with 300 particles or 300,000 particles may not matter if the virus is energetic enough in its reproduction. A match can light a fire big enough to bring down a house; even a Molotov cocktail may not do that, if it lands in a swimming pool.
Of course, the whole concept of Michael Mina's infectivity argument is that people go through a phase in which they are just stoking up production in their nasopharynx, maybe have 100,000 virions day 1, but by day three, they've got 3 million and by day 6 back down to 100,000. He has argued the patient is only infectious at the 3 million stage, so the dose he spews out might matter. But that is not an argument that the guy who gets sick is the guy who gets the big dose; it's an argument that the big dose may be needed to gain a toe hold in the nasopharynx in the first place; what happens after that may depend more on the host than the dose of inoculum. (Whether the match lands on the gas range or in the swimming pool.)
Of course, the next idea is that it's not free virions in the air that matter so much as droplets carrying millions of viruses which provide enough virus to infect, so maybe it's the package which delivers that matters.
Masks likely work by shielding from droplet borne infection and in some ways you might argue that they reduce the dose of viruses but this is unsettled. Again, this is more important to whether the virus can gain a foothold, not what happens once it's dug in.
3. HERD IMMUNITY:
May not be possible from natural infection with SARS COV-2.
Corona virus elicits "sloppy immunity" and in the case of the two coronaviruses which have caused the common cold, reinfections with genetically identical viruses happen two or three times during a single season. This is what has made a vaccine for "the common cold" so difficult. Patients with reinfection with the same genetically identifiable SARS COV-2 isolate have been documented. I don't recall how many, but some case reports at least have accumulated suggesting the second exposure to SARS COV-2 does not always result in a milder case.
This discussion led Brianne Barker, the TWiV immunologist, to say that given the brief duration of immunity, which is not sterilizing (killing virus) but only neutralizing, herd immunity from naturally acquired infections is not at all a given. She hastened to add that the immunity from vaccines against the spike protein may confer longer immunity and more durable immunity. Immunity from vaccine may be better than what you get from having the disease.
The consensus among the panelists and their guests has been this coronavirus, like other conronaviruses, will never leave human populations: There will be no small pox vaccine for it. We'll have it with us for the foreseeable future, hopefully controlled like influenza, with annual vaccinations.
So that's my, possibly faulty, recall of TWiV wisdom acquired over the past few months as these topics have been raised, discussed, rehashed multiple times.
If I'm far off, I don't think I'm very far off.
* I was very proud for my restraint when I heard that. I did not say, "Oh, you know what I heard? It wasn't actually the Chinese in that Wuhan lab. It was those aliens they are keeping in Area 51 who made that virus! Good grief, stop listening to Breitbart and Rush and Aryan Nation Speaks and tune into This Week in Virology."
