What We Do—and Do Not—Know About Herd Immunity
![](https://media.wnyc.org/i/800/0/l/85/2020/08/AP_20134688453281.jpg)
Spanish health officials say large-scale testing for the new coronavirus has demonstrated there is no herd immunity in the country.
( AP Photo/Emilio Morenatti )
( AP Photo/Emilio Morenatti )
Produced by Meg Dalton
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