What is most important in spreading COVID-19? The NFL figured it out.

Public health officials have been caught off guard about the transmission of COVID-19 since the beginning of the pandemic. The CDC famously gave bad advice, including not wearing masks at the beginning of the pandemic, and failed entirely at setting up testing in a timely matter. 

In contrast, as efforts to manage the infection evolved, one organization knew that control of COVID-19 meant everything to their multibillion-dollar business: either they control the infection, or they lose everything. That business was the National Football League, and their successful experience is now published by the CDC. 

The NFL did not feel they could isolate in a bubble the way the NBA and NHL had given that the games had to be played in large stadiums, out of doors, and involve many more individuals than the smaller team sports. Their response was to aggressively pursue contact tracing and isolate anyone suspected of being infected with SARS-CoV-2/COVID-19.  In this process, they developed some of the best insights into controlling the spread of infection with coronavirus.

From Sept. 27 to Oct. 10, there were a total of 41 COVID-19 cases in the NFL. Twenty-one were believed to have come from transmission within an individual team,  a finding documented by virus genomic sequencing. Those cases were crucial to understanding transmission dynamics. 

Remarkably, 12 of the cases had no close interactions of at least 15 consecutive minutes with a confirmed positive individual. Eight had no interactions of even five consecutive minutes. Seven had no interactions that cumulatively added up to 15 minutes with any confirmed positives. So, the amount of interaction required for transmission was much less than what was being touted by the CDC. 

“That was a wake-up call,” said Dr. Allen Sills, the NFL’s chief medical officer. “We had to be more precise in our definition of high-risk close contacts because clearly transmission could occur outside those basic boundaries of time and distance.” “It goes back to those four basic things we talked about in the paper with cumulative time, distance, ventilation, and masks. If you think about those four factors as being four different quadrants, if you’re failing in two or more of those, then that’s going to become a high risk for a transmission,” Sills said. “I always talked about the big three, which was: meeting, eating and greeting.”

Based on this information, the NFL moved away from the CDC’s “within six feet for more than 15 minutes” exposure rule. Anyone who was exposed regardless of duration had to spend five days testing negative in isolation in order to return. In an article outlining their success in the Wall Street Journal, Jeff Miller, the NFL’s executive vice president who oversees health and safety said, given the data the “NFL had to adapt and change our approaches.”

The league introduced strict rules for any team with even a single positive. It started testing seven days a week (instead of six) and increased its contact tracing to consider the context of interactions along with player and coach movements they were already monitoring through tracking devices. 

With this approach, for example, a masked encounter outdoors was treated differently than an unmasked shared car ride. The NFL made team meetings virtual, avoided indoor gatherings, even if they were distanced, and quit eating together. If someone had done any of these things with a person who subsequently tested positive, they had to be isolated, regardless of how brief their interaction had been. This allowed them to complete their entire season and not cancel a single game.

As you watch the Super Bowl next week, realize the NFL’s biggest accomplishment this year might not have been on the field.