Thread by @fitterhappierAJ

A fact then a bit of speculation as my contribution:

fact: Naive T cells are a correlate of protection independent of age (but it correlates)

Speculation: As sars cov 2 infections greatly deplete Naive T cells, there may be a point where decompensation occurs (less protection)

Of course this is a dynamic relationship where other elements of the immune system can contribute to protection like antibodies and primed memory

But there is a natural sloughing and aging of the immune system

More to come on this

In cases where there is antibody escape the T cell dynamics are weighed more heavily, which is what we see often with these sera-evading variants and with titer waning

This flies in the face of the people who believe and claim repeat infections will confer greater and greater immunity

The "double hybrid hamburger immunity" as @james1chas3 puts it

They are incorrect. As long as titers wane there can be reinfection and immune aging

I believe once the Naive and Tscm T cells are greatly reduced there will be a decompensation and more severe illness, where there are not antibody titers

People have invoked many theories as to why this may be, including an energy allocation theory and lack of repertoire diversity.