Djokovic replied

 "The principles of decision making on my body are more important than any title or anything else. I'm trying to be in tune with my body as much as I possibly can." He went on to add, "I was never against vaccination. I understand that globally, everyone is trying to put a big effort into handling this virus and seeing, hopefully, an end soon to this virus."

https://www.republicworld.com/sports-news/tennis-news/will-novak-djokovic-compete-at-us-open-read-latest-update-on-vaccination-rules-articleshow.html?