You shouldn't even be having the vaccine if you might have such a reaction was my understanding, with this information ascertained during the booking process.
Yeah I said that earlier and he's 26 and otherwise very healthy, so he will be very far down the list anyway.
By the time he gets it, hopefully they will have found a way round that and it will be safer for all concerned.
But he and I want him to have the jab in future for his own safety and ability then to get out in the world, when we get back into more normality.