vaccination programs are rolling out with remarkable speed, glimpses of a post-pandemic future are starting to appear: Schools have mostly reopened, family gatherings are being planned and summer vacations may be just over the horizon.But move away from this handful of rich countries, and a darker reality emerges: The virus is still rampaging around most of the planet, and uneven vaccine distribution poses a major public risk as variants emerge.Since mid-March, Covid-19 deaths have started trending upward again worldwide even as the numbers improved in the U.S.