We think more lives would be saved by providing as soon as possible (a) just one dose of vaccine (b) to all people who face the highest risk of dying from Covid-19, whatever the reason (advanced age, other medical conditions, severe obesity), and (c) just forgetting about any boosters for a while, maybe even a very long while. Second doses should be deferred for the time it takes to achieve this primary goal.

The two vaccines’ manufacturers and the F.D.A. have been reluctant to endorse any change to the vaccination schedules that were tested in Phase 3 clinical trials, on grounds that other options weren’t tested and so their efficacy is unknown. On the face of it, this position seems sensible; yet under current circumstances, it is dangerously overcautious.

The C.D.C. has authorized giving a second dose up to six weeks after the first one if sticking to the recommended interval is “not feasible.” But this is an arbitrary extension — it wasn’t tested any more than any other modification — and we think it’s too short to accomplish much good society-wide.