That means "any" COVID- or vaccination-related discussion, same as "any" political or religious discussion was already discouraged as part of the server rules. Regardless of how well-intentioned the discussion might have been, it is still prone to creating the same unnecessary disruption in the game. People come here to play and have fun, so we will steer away from anything that is unnecessarily divisive and doesn't help enjoy the game.
Thanks for your cooperation, and feel free to use the General Discussion forum for any such topics.