Friday, July 10, 2020

Genetic Variation and Strain




The Steele Dossier prompts an important question: To what lengths will a politician go to advance himself? What is beneath a politician?


                            Genetic Variation and Strain

A reader of Cowen offers two theories on the virus and its variable behavior:

1. Genetic variation

This means variation in the genetics of people (not the virus). We already know that (a) mutation in single genes can lead to extreme susceptibility to other infections, e.g Epstein–Barr (usually harmless but sometimes severe), tuberculosis; (b) mutation in many genes can cause disease susceptibility to vary — diabetes, heart disease are two examples, which is why when you go to the doctor you are asked if you have a family history of these.

It is unlikely that COVID was type (a), but it’s quite likely that COVID is type (b). In other words, I expect that there are a certain set of genes which (if you have the “wrong” variants) pre-dispose you to have a severe case of COVID, another set of genes which (if you have the “wrong” variants) predispose you to have a mild case, and if you’re lucky enough to have the right variants of these you are most likely going to get a mild or asymptomatic case

2. Strain

It’s now mostly accepted that there are two “strains” of COVID, that the second arose in late January and contains a spike protein variant that wasn’t present in the original ancestral strain, and that this new strain (“D614G”) now represents ~97% of new isolates. The Sabeti lab (Harvard) paper from a couple of days ago is a good summary of the evidence
. https://www.biorxiv.org/content/10.1101/2020.07.04.187757v1

— note that in cell cultures it is 3-9x more infective than the ancestral strain. Unlikely to be that big of a difference in humans for various reasons, but still striking/interesting.

Almost nobody was talking about this for months, and only recently was there any mainstream coverage of this. You’ve already covered it, so I won’t belabor the point.

So could this explain Asia/hetereogeneities? We don’t know the answer, and indeed it is extremely hard to figure out the answer (because as you note each country had different policies, chance plays a role, there are simply too many factors overall).

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