Peter Lederman in Second Bout With COVID-19

Well, some of us, maybe more than a few, ARE.  I am a PhD in virology, worked (retired now) for a huge international pharmaceutical company; in vaccine development.  Lew is one too.  Scientist I mean.  

Iso, the mRNA vaccines contain:

-the purified synthetic mRNA encoding the COVID surface glycoprotein
-4 lipids; one is cholesterol, one is phosphatidyl choline, one is a cationic lipid that helps the lipid nanoparticle deliver the mRNA to the cytoplasm/ribosomes, and one is a PEG lipid.
 -There are the usual salts, pH buffers, maybe a few sugars.  

But that is it.  

The mRNA in the Moderna and Pfizer vaccines actually encode only a few hundred or fewer amino acids of one specific region of the surface glycoprotein, S, which is overall about 900 amino acids in length. That region being the Receptor Binding Domain. Thus they both elicit a panoply of antibodies directed only at that domain. Given the absolute dependence of the SARS-CoV2 virus on the ACE2 receptor for entry into cells, that is likely to be why the two vaccines work more or less on every variant so far known; there is only so much genetic variability in that domain that will still permit efficient receptor binding. In effect, the capacity of the virus to evade the immune response elicited by the vaccines without a reduction in its binding affinity for ACE2 is very limited. Woe unto us if the virus ever "learns" to use some other cellular surface protein as its ticket to cell entry. Most other human pathogenic viruses are not so limited as is SARS-CoV2.