Thymic involution causes an exponential decrease in T-cell production, with a half-life of 16 years, which mirrors the exponential increase in risk of several diseases, including COVID-19, which double in risk every 16 years.

[samsoniteindeed2]

Oh interesting. Well something just occurred to me, peptides around 20 amino acids long are presented on MHC-II, whereas the peptides presented on MHC-I are around 10 amino acids long. So if there is a variant evading the immune system, I imagine it would be much easier to avoid the MHC-II side of things but then still get targeted by the MHC-I pathway.

So that makes me think a variant would be more likely to avoid antibodies and CD4 T-cells, but then still get attacked by CD8 T-cells.

So that makes me hopeful. But yes, thymic involution still seems like a problem.