We don’t have strong evidence either way. Neither choice—vaccinated only or both—is unscientific. (It is understandable that, without reliable proof, the unvaccinated would be barred.)

In any case, this is a problem we need to solve soon. The mRNA platform looks promising. We don’t want to back into a future where a diseased minority is barred from our urban cores. Particularly if they pose little risk to others.