So far 1.5M have died from COVID worldwide. Let's say that without a vaccine that number could be expected to grow to 10M or 20M. To prevent that outcome, we're talking about giving vaccines to billions of people, most of whom are at very little risk from the virus, which use previously-unknown mechanisms to induce immunity, and whose long-term effects are completely unknown. It seems to me like there's not really serious calculation being applied to the risks of the latter course. It's just "stop COVID at all costs."