@hansw Oh and WRT tot he virus going away... In all liklihood it wont, even with a vaccine. It is hard to say for sure right now, and there is of course a chance what I'm about to say wont be the case. But in my opinion even if the vaccine does not turn out to be dangerous and provides some level of immunity as we have already seen, it is unlikely that it will be able to cause the virus to go away or even to be particularly effective in general. But we wont know for sure until a few years are up.

But based on the pattern of past attempts at vaccines of other viruses in the coronavirus class of viruses, as well as based on what we know of live coronavirus' that are well studied as well as covid-19 specifically, which is less well known, everything suggests a vaccine is likely going to be a mostly futile long term effort and will be pulled from normal use even if it doesnt prevent safety concerns.

The reason being the immune response we see to all coronavirus class viruses and which appears to be the case with covid-19 as well.

You see viruses of different classes provide very different immune responses where one will be immune once recovering for some range of time.

Consider a few different viruses from different virus classifications...

Chickenpox, of the class herpesvirus, behaves like all viruses of that class in that you have an initial outbreakm, of which you have lifetime immunity to having the initial outbreak again, but then will continue to get future outbreaks for life that are less severe or take on a slightly different quality (in this case shingles). Herd immunity here is impossible due to the early onset of disease and the fact that the vaccine is given at a late age

Flu are influenza class. Immunity to this lasts 1 year. The reason for this is not due to a reduced immune response per se but due to viral recombination. Regardless this are effective for ~1year max. Herd immunity is impossible here due to reduce immune period.

Tetanus Are bacterial class infectious agents, they have a 7 year immune period before reinfection is possible, no herd immunity possibe...

So as you can see we know most viruses we cant develop herd immunity and they are with us forever regardless. When we look at coronavirus then what pattern do we see? Well luckily there are a lot of viruses of the class with a lot of research. In short, immunity lasts depending on the severity of infection. Asymptomatic carriers are able to be reinfected in as little as 2 weeks. Severe clinical infections appear to remain immunity on the order of 1 - 2 years at most. In all experimental vaccines we have tried on viruses of this class (that I know of) the immune response was very weak meaning for most normal doses immunity only lasted a few months at best. Moreover upping the dose caused high risk from complications with only minimal improvement on the period in which people remain infected.

So in all likelihood the covid vaccine will fail for the same reason all the other coronavirus vaccines fail.. At any dosage that is safe for the patient the immunity is effective but only for a fairly short period, so short in fact that the vaccine is effectively useless. More importantly herd immunity is entirely impossible.