For all the amazing benefits of the mRNA coronavirus vaccines, there are limitations. The effectiveness wanes. New variants evolve faster than shots can be adjusted. Destructive disinformation about their safety lingers. Yet, the vaccines are critical to battling disease and death — and that also goes for the next generation of boosters coming soon. Critics might raise fresh concerns about these new shots, and there are some things the public should know. But the latest booster, as with all the previous shots, promises to be a life raft in dangerous seas.