It is the spike protein that allows entry into the ACE2 receptors.
Apparently the spike protein is the part they are trying to get an immune response to. Hence, if it works it will stop the virus getting to the receptors.
If the virus mutates so it doesn't have the spike protein then it can't infect people anyway.
In simple terms, the experts are hopeful. However, they do not know if it will provide long term immunity and may need booster shots.
Maybe it will be yearly, possibly five yearly.
Seeing HCQ doesn't seem to be a preventative or treatment, we better hope we have it by the end of March.
(Self interest noted: I have made a bet with a friend that it will be available by 31st March)
