The University of Oxford team developing the Astra Zeneca vaccine has privately advised HM Government that they have hit the nail on the head, although they are publicly hedging their bets (source: former leader of one of the two major political parties). Phases 3-6 or something like that of the trial have started and I'm trotting along to be jabbed on Monday morning for a 12 month commitment for phase 4 I think. Astra Zeneca is starting production now, to deliver 30 million doses to the UK by autumn, and it has established commercial arrangements with a number of other manufacturers to deliver hundreds of millions of doses for other European countries and billions of doses in developing countries over the next year.
My personal view is that, considering the fatality rate in under 55s is considerably less than seasonal flu, and I certainly don't bother with a flu jab every year, this is largely going to have a placebo effect to calm down panicked internet Karens, while enabling world governments and the WHO to climb down and descalate without making embarrassing public apologies for getting the whole thing completely wrong. The most ironic thing being that much of the public that actually travel won't be eligible for the vaccine as it will go to the over 55s first (in the UK at least).