Deirdre is referring to Dr. Zubin Damania, MD, aka ZDoggMD. This guy is pro-vaccine, but said boosters are only for people at risk, judging by his youtube shorts.
Source: https://m.youtube.com/watch?v=b9Chgh5CQcE
Source: https://m.youtube.com/watch?v=7JYFTGs4D-E
96% of doctors are...