Personal anecdata(source: had covid-infected roommate, and close contact with someone who tested positive a day later): I got boosted 2 weeks before my roommate

Personal anecdata(source: had covid-infected roommate, and close contact with someone who tested positive a day later): I got boosted 2 weeks before my roommate got covid, I took no precautions and didn't get sick. The second contact was the beginning of this week and didn't get sick. As far as I'm concerned, vaccines have kept me from getting covid in known-risky environments.