By Kevin M. Esvelt and Marc Lipsitch 

We are barely a week into 2021 and already there are urgent warnings about a novel pandemic virus strain spreading surreptitiously and exponentially across the world.

This seems like déjà vu. But in a sense that’s a good thing: This is not just another chapter in the exhausting saga of SARS-CoV-2, the virus that causes Covid-19, which newly available vaccines will slowly bring under control.

Humanity wasn’t remotely prepared for our struggle with SARS-Cov-2 when it emerged late in 2019. So we lost to it.