The race to develop a vaccine against covid-19 was a matter of life and death. A recent study found that in 2021, 20m lives were saved by the jabs. Researchers at Airfinity, a life-sciences data firm, have used those numbers—along with data on which shots were most widely administered in each country—to estimate which one averted the most deaths.

Airfinity found that more than half of lives saved around the world could be attributed to just two vaccines.

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