| Let me attempt to give a defense of "first shots first" as someone who initially wrote it off as foolish, and later came round to it. In an ideal world, you'd do a few clinical trials and figure out the optimal dose regime and timing. (I'm not really sure why they didn't run 5 parallel trials with different timings to begin with). In the world we inhabit, alas we didn't have those studies. But that doesn't mean we have no reason to believe that the first shot is protective! You can still look at how vaccines in general work, and our basic understanding of immunology. In general, for vaccines with multiple shots, the model seems to be that the first shot gets you >50% of the protection, and the second shot mainly extends the protection over time. This might not be how the COVID vaccines work, but your priors should be fairly strong that this is what the clinical trials will ultimately show, because that's what they have shown for a bunch of different vaccines with different mechanisms. If you're in an ideal world where inaction doesn't cost you anything, sure, do the studies. In the world we inhabit, thousands were dying every day, and so inaction is morally horrifying. Giving a pair of doses as first shots to two >65yo results in far fewer people dead than giving that pair of doses as a full course to one 65yo. The expected value is pretty clear on this one, even though the clinical trials were not. You should probably have started to feel tentatively confident that the first-dose-first strategy was sound circa mid-Feb, when it the UK's death rate had been falling rapidly for about two weeks: https://lh4.googleusercontent.com/GGlgMxEKIoaxyuZbuHjjEBH2er... -- while it's hard to disentangle lockdown effects, EU vs. UK was mainly a difference between "locked down with vaccines" and "locked down without vaccines", at risk of oversimplifying. If I had to summarize in a sentence: use Bayesian reasoning rather than applying unjustifiably strict error bars on your decision process. |
In the US, though, I don't think we have ever been forced between these two scenarios: we have always had enough vaccine doses for people in our high risk classes. The question thereby is more whether it is better to have all the essential workers and everyone over 65 years old along with maybe third of everyone else with a single dose or to have the first two classes of people fully dosed... and "I dunno", right? ;P