The Centers for Disease Control published a scientific paper jointly authored with the NFL on Monday detailing efforts the league made to get through the pandemic-altered 2020 season.

The paper references what the league did in terms of limiting the spread of COVID-19 among its 32 teams. The study says elements can be applicable beyond the NFL to limit the spread of the virus, including “to settings such as long-term care facilities, schools, and high-density environments.”

The NFL was able to complete its regular season and the playoffs on time with only the Super Bowl remaining. The defending champion Kansas City Chiefs and the Tampa Bay Buccaneers will play for the title on Feb. 7 in Tampa, Fla. A limited crowd of about 22,000 fans will be allowed at the game.

The NFL found that transmission of the virus occurred in less than 15 minutes of cumulative interaction between individuals, the timeframe initially used in the CDC’s definition of “close contact.”

The paper showed that from Aug. 9 to Nov. 21 approximately 623,000 COVID-19 tests were performed on approximately 11,400 players and staff members and 329 tested positive (2.9%).

From Sept. 27 to Oct. 10, a total of 41 cases were identified among players and staff members. Of those, 21 were believed to have resulted from within-club transmission at a single team, requiring closure of that team’s facilities.

The league then added a more intensive protocol starting in October, including the start of high-risk interaction tracing and daily testing. On Nov. 21, a league-wide adoption of the protocol was mandated though the end of the season.

The paper noted at least three limitations:

– The metrics from wearable devices rely on people using them.

– Determination of high-risk contact status is based on interviews and “subject to recall and reporting bias.

– Household exposures are based on self-report.” And the source and date of transmission of the virus cannot be confirmed.