Small Gatherings Spread the Virus, but Are They Causing the Surge?

As states struggle to contain the resurgent coronavirus, many officials are laying the blame on an unexpected source: people gathering with family and friends.

Household get-togethers undoubtedly do contribute to community transmission of the virus. Canada’s recent Thanksgiving certainly added to its rising cases; such an increase may happen here, too, as the United States embarks on a holiday season like no other. That’s why the Centers for Disease Control and Prevention on Thursday warned so strongly against gathering with others outside the household during Thanksgiving.

But are dinners and backyard barbecues really the engine driving the current surge of infections? The available data do not support that contention, scientists say. Still, the idea has been repeated so often it has become conventional wisdom, leading to significant restrictions in many states.

In dozens of statements over the past weeks, political leaders and public health officials have said that while previous waves of infection could be linked to nursing homes, meatpacking plants or restaurants, the problem now is that unmasked people are sitting too closely in kitchens and living rooms, lighting thousands of small Covid fires that burn through their communities. ...

Household gatherings have “become a major vector of disease spread,” the Health and Human Services secretary, Alex Azar, said in an interview with CNN in late October.

But many epidemiologists are far less certain, saying there is little evidence to suggest that household gatherings were the source of the majority of infections since the summer. Indeed, it has become much harder to pinpoint any source of any outbreak, now that the virus is so widespread and Americans may be exposed in so many ways.

“Somebody says something, and somebody else says it, and then it just becomes truth,” said Julia Marcus, an infectious disease epidemiologist at Harvard University. “I worry about this narrative that doesn’t yet seem to be data-based.”

Most states don’t collect or report detailed information about the exposure that led to a new infection. But in states where a breakdown is available, long-term care facilities, food processing plants, prisons, health care settings, and restaurants and bars are still the leading sources of spread, the data suggest.  ...