There have been (are) studies for the protection against Influenza A, in ferrets... Maybe something along those lines would be a booster-type treatment for humans down the road.

Though, according to Dr Fauci, yesterday; there's a lot of work ahead to see what current vaccines' reactions would be with the elderly, diabetics and those with heart disease... Along with the obese, which we know there are tens of millions of them, sadly.

I also see that Brazil isn't too happy with the vaccines they're receiving from China... Way too much for me to read or comprehend.