There has been a lot of focus recently on the role of small gatherings in the national jump in cases. But those aren’t the main culprits, says Ellie Murray, an epidemiologist at Boston University’s School of Public Health.

According to state health department reports, the largest sources of coronavirus infections are workplaces like meatpacking plants and warehouses, institutional settings like prisons and retirement communities, and businesses like restaurants and bars, Murray tells All Things Considered.

“We have seen really large spread happening from things like bars especially and other kind of indoor gatherings like that, where people spend a long time in proximity with a lot of people,” she says. “And I think that those places need to be closed down, for at least until we can get a handle on the current surge.”