All I know is I have two neighbors who are nurses for the local hospital. Both got their vaccines last year and went in for their booster and both got covid from it (actual symptom covid not tested positive but where fine).

Both said they were a little unwell after the second shot but felt great and now wouldn't get covid (when they were trying to convince me to go get it). Weird that the entire covid thing, working up close with people, they didn't get it until they got the booster.