Why easing COVID restrictions too soon could be boon for variants

COVID-19 vaccine rollout has accelerated to more than 2 million shots per day in the United States. A more transmissible coronavirus variant from the U.K. is muscling its way across the country. And governors from Texas to Massachusetts are racing to loosen mask mandates and strictures on gatherings and reopen gyms, restaurants, workplaces and schools.

For a virus in search of new ways to spread and sicken, this convergence of events is a moment of unique opportunity, and new research underscores the peril.

Two studies published this week in the journal Science explore some of the circumstances that are known to give rise to new genetic variants of the SARS-CoV-2 virus.

In both a mathematical modeling exercise and a genetic deep dive into 1,313 coronavirus samples, researchers show that worrisome