The important point that you will never hear in the mainstream media is that Novak Djokovic had the virus and recovered back in June, and as such he has no need of a vaccine that is at best not very effective and at worst potentially dangerous.
Why would anybody want to be guinea pig for an insufficiently tested technology when your own immune system has proven that it is up to the task and and in it's wake, installed stronger defenses against further attacks?? Would you fly in a plane using "beta test" software when you had the choice of a proven good plane??
RB.