Canadian Snowbirds heading home-Antigen Rapid Tests required

Go read the study, it wasn’t done in a lab

Here are other recent (2022) non-lab studies that found masking was effective at reducing secondary attack rates
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South Africa (beta and omicron) does not have a government vaccination mandate, some employers do.

Back to your original question; until there is a test for immunity simply saying if someone was sick they can be considered immune is a scientifically flawed policy.

This tread is now yours, I have work to do.