So the U.S. is looking good, using the most effective vaccines while sticking with the science. So far, more than 25 million Americans, over 7 percent of the population, have received at least one dose. The country is likely to move even higher in the world rankings as its vaccine supplies expand.

In part, the U.S. is doing this well because of its baked-in advantages. Above all is wealth. America has bought its way to the front of the line, spending billions of dollars on purchase agreements with half-a-dozen vaccine manufacturers. Both FDA-authorized vaccine manufacturers are U.S.-based companies. Low-income countries rely entirely or largely on COVAX, the global system for vaccine distribution—which is expected to cover, at best, 20 percent of countries’ populations by year’s end. Wealthy countries have bought up most of the world’s supply, leaving little for others. The U.S. also has a well-developed public health infrastructure, including the ability to keep vaccines in ultra-cold storage.

Meanwhile, many other wealthy nations have faced their own struggles. European countries are experiencing shortages in vaccine supplies. Delays of the Pfizer vaccine while it refurbishes its Belgium facility have plagued the European Union, while too few nurses available to distribute the vaccine have made things even worse. A deep rift has formed between the E.U. and U.K., with politicians competing for scarce supplies.