Hmmm. But there have also been a fair number of studies in people where they look at how many vaccinated people get sick compared to how many unvaccinated people get sick, and those studies *also* say that protection wanes, e.g.:

UW study takes a closer look at vaccine effectiveness against newer COVID strains | CBC News

It can take a long time to create a new vaccine and at the same time, there have been many evolutions and new strains of the COVID-19 virus. University of Waterloo researchers wanted to understand whether those vaccines are still as effective as they should be?

CBC (www.cbc.ca)

Analysis: Last year's COVID vaccines protected well against severe illness

CIDRAP (www.cidrap.umn.edu)

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(22)00801-5/fulltext#%20

Yeah, kinda why I get mad when doc tests for antibodies when deciding if I need to get revaccinated for things like Hep B and all that. I don't mind the vaccinations but do wonder how necessary they really are if just based on antibodies being low.

Antibody waning ≠ protection waning

A common conceptual error in public communication (less so in research) is conflating falling antibody titers with falling protection. In immunology, the memory B-cell and long-lived plasma cell compartments serve as reservoirs that can rapidly regenerate high-titer antibody responses upon reexposure, even when circulating titers are low. Studies that only report titer decline at fixed intervals miss this reactivation capacity entirely.

I think a big difference in studies is that some merely study antibodies vs. the full immune system, as does this one. Antibody levels do drop after the initial immune response—but studies that measure memory B cells, memory T cells, and long-lived plasma cells typically find much more durable protection. 2/2