The Biden administration’s decision to begin sharing U.S.-authorized COVID-19 vaccines with the rest of the world is welcome news. Now coronavirus czar Jeff Zients, who will lead U.S. efforts to fight the pandemic abroad, must swiftly craft a global vaccine strategy that’s as focused, ambitious and effective as the one that’s worked so well domestically.

Those who ask whether the U.S. ought to assume this burden should remember two things.

A version of this editorial first appeared in Bloomberg.