Dec 25, 2021Liked by John Skylar, PhD

Hello John,

We met in the hallway in DC last week. Sorry it took me so long to find this site. I have one comment and one question.

Comment: As a retired physician, I think that you give doctors too much credit for understanding how the vaccine and someone's personal health problems might interact. Doctors have far less time to read articles and mostly will know less than you will about the vaccine side effects. They at this point are making decisions based on their own experiences which will be, at best, anecdotal. I have more time to read scientific literature now that I'm retired, and I have found almost nothing that would allow me to make a fully informed recommendation on which vaccine to use for any specific patient.

Question: I may have missed earlier posts covering this, but I have been wondering if my early information about the mechanism of infection is still valid. I understand that the virus spike protein binds to ACER2 receptors, after being cleaved by the enzyme(?) furin. These ACER2 receptors are, I thought, deep in the sinuses and lung mucosa. If so, that would make the initial viral invasion possible only through deeply inhaled aerosol particles. Is that true? Have other binding sites been identified?

Also, I've been wondering how the circulating antibodies produced by the vaccines can be of any help at all in preventing this initial surface invasion. Is this why the vaccine seems best at preventing severe disease (which would require some form of viremia) and not at preventing mild URIs or, sadly, transmission?

Lisa Freitag, MD

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Dec 22, 2021Liked by John Skylar, PhD

PF4 antibodies are also implicated in HITT (heparin induced thrombocytopenia and thrombosis, a particular rare adverse reaction to heparin), so that's interesting. Also fully agreed that boosters should be incorporated into the definition of "fully vaccinated".

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Hi John,

Happy that you are recovering nicely from the plague. I would like to plan some travel for when the risk level fades again. My sense of omicron is that it is spreading so fast that we are seeing a huge spike that will burn itself out fairly quickly once a critical mass is infected. In the current state of the world, what models would you turn to for guessing what the covid situation will be in Country X in Month Y? https://covid19.healthdata.org/united-states-of-america seems pretty easy to use, but I wonder how good their models are.

Thanks again for your great service.

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Question: each variant is described in terms of a series of mutations, but what’s the reference sequence the mutations are relative to?

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Maybe over a year ago my friend’s teenage son came home from school with Covid. He infected his brother, mother and father. No one was hospitalized and they all recovered. Later they all got the first two vaccine shots. Then the mother got the third. The other day I had a social lunch planned with my friend. He called to tell me that maybe we should cancel it. One of the sons came home with Covid and infected his brother and mother. My friend the dad had not been infected yet. As I have not been vaccinated and don’t intend to be I agreed that we should cancel our lunch. The vaccines seen useless to me.

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