I was just blown away by TWiV 855: "T time with Alessandro Sette" from the La Jolla institute for Immunology. (That's on YouTube.) His lab has done intensive studies of how T-cells work with Covid vaccines and variants. They've looked at how HLA proteins present virus protein fragments on the infected cell surface to yield literally thousands of different T-cell epitopes immune systems can react against. They also looked at how variant mutations can evade those T-cell epitopes. Unlike antibody evasion, T-cell epitope evasion doesn't seem to exhibit any evolutionary pressure: It's random. And it has no benefit to the virus when it gets transmitted to another person, because that person will have different HLA types and different virus protein fragments their T-cells reacted to when they got immunized!

All this is exactly why vaccination is so effective at keeping infected people out of the hospital despite antibody contraction. He also said they looked at immunity following infection versus vaccination. About 10% of those just infected end up with no immunity after some months because natural infection has so many variables. Vaccinated people have much more uniform immune responses, probably because they had a much more uniform exposure to antigen.

The number of experiments required to get all his data is astonishing. These people know a whole lot about this virus.

Educating anyone benefits everyone.