On the question that came up re: whether you can get another COVID-19 vaccine (if it approved) if you’ve already had a trial COVID-19 vaccine of a different sort:
We recently qualified to join one of the COVID-19 trials. During the informational session, they told us that it’s always an option for folks to drop out of the trial in order to take a different vaccine, if another better choice comes along. As far as whether there’s risk to doing so, the answer boiled down to: Technically the answer is that it’s not known without a study, but the probability is low, especially if the mechanism of action is different.
And on the separate question someone raised re: how people would know you were “safe to be around,” safe not to wear a mask, etc., after a vaccine:
That specific question did not come up, but one thing that has been clear lately is that no vaccine is 100% effective. When the Pfizer vaccine was declared 90% effective, that was taken as stunning news; medical professionals had thought 50% effective would be a reasonable number. So - even having a proven fairly effective vaccine doesn’t guarantee that you’re safe to be around, don’t have to wear a mask, etc. It just means that your probability of contracting the disease is lower than it would be otherwise - just as taking the annual flu vaccine doesn’t guarantee you won’t get flu, but reduces the probability.
Because COVID-19 is so much more serious than the common flu, both in terms of mortality rate and long-term sequelae, we would likely continue to wear masks even after taking a proven effective vaccine, until the prevalence of COVID-19 in the general population became very low. The vaccine would help our peace of mind, but it wouldn’t make us bulletproof, particularly if the pandemic were still raging in the population at large, as it is now.