Well, the more basic problem is the use of "or" in the headline ...
"Natural Immunity OR Vaccine"
... and then the use of "and" in the body of the article ...
"... those who had Covid-19 in 2020 AND were fully vaccinated ..."
... means the grudge match between natural immunity and the vaccine teased in the headline quickly became a tag team of the two against unexposed and unvaccinated in the body of the article.
The essential American soul is hard, isolate, stoic, and a killer. It has never yet melted. ~ D.H. Lawrence