https://www.thelancet.com/journals/l...465-5/fulltext
Lots of previous discrimination against people who were previously infected but not vaccinated who would have had the same level of immunity as a vaccinated person (Neither vaccination or previous infection seems to stop transmission, but both seem to mostly prevent severe disease.)
This was said early on the pandemic but “the experts” refused to acknowledge this in public policy. Any previous vaccine mandate should have acknowledged previous infection; some European countries did but here it was all about making sure we used those shots we paid for in advance. The US still has a vaccine required for entry.