Wish I had known this when I got Covid last year. I had gotten my booster about a month or two before catching it and for the first day or so of having it I kept get negative tests even though both my dad and brother, who were just beyond the period of vaccine effectivness, got positives right away. I only got a positive from a PCR test and subsequent at home test about 3-4 days after my initial symptoms showed.

My mom is vaccinated, but hasn't gotten any subsequent boosters after the 3rd booster.