To justify their reopening decisions, governors point to falling case counts. “We make decisions based on facts,” Cuomo said. “New York City numbers are down.”

But epidemiologists and public health experts say a crucial factor is missing from these calculations: the threat of new viral variants. One coronavirus variant, which originated in the United Kingdom and is now spreading in the U.S., is believed to be 50% more transmissible. The more cases there are, the faster new variants can spread. Because the baseline of case counts in the U.S. is already so high — we’re still averaging about 130,000 new cases a day — and because the spread of the virus grows exponentially, cases could easily climb past the 300,000-per-day peak we reached in early January if we underestimate the variants, experts said.

Furthermore, study after study has identified indoor spaces — particularly restaurants, where consistent masking is not possible — as some of the highest-risk locations for transmission to occur. Even with distanced tables, case studies have shown that droplets can travel long distances within dining establishments, sometimes helped along by air conditioning.

We’re just in the opening stage of the new variants’ arrival in the United States. Experts say we could speed viruses’ spread by providing them with superspreading playgrounds or slow them down by starving them of opportunities to replicate.