How long does it last for?
We don't know, which is why follow up will last until at least 2023
When will it be known is a booster is needed and at what interval?
That should follow from the continuance of the trials - the enrolled participants are about 6 months ahead of the general population, so there should bee at least at length of time as warning of need to plan a booster programme.
Is it true that the vaccine only reduces the symptoms if the person still catches cv?
It seems that is a definite effect, plus there's a decent amount of evidence that it also prevents transmission. That does not hiowever yet reach the required level of evidence yet for tat aspect to be relied on. But the amelioration of the disease is in itself a worthwhile benefit
Is it 1, O or more serious side effects as even Pfizer cannot make up their minds?
??
If there is no evidence to say that it stops you infecting someone else, does this mean masks are to continue indefinitely
Probably not - if the disease becomes as trivial as a cold, would widespread centrally-imposed restrictions be needed? Doubt it. But I think now that mask-wearing has begun, there will be people who continue (either all the time, or when they have a lurgy they do not want to spray around)