CDC looks at lessons learned from NFL's testing and contact tracing protocols

• The league along with the NFL Players Association identified four factors when players and staff came in contact with each other: whether masks were in use, how well the room was ventilated, how long the interaction was and the physical distance between the two parties.

By the numbers: About 623,000 COVID-19 tests were performed on approximately 11,400 players and staff members and nearly 3% tested positive between Aug. 9 and Nov. 21.

• Between Sept. 27 and Oct. 10, a total of 41 cases were identified among players and staff. Of those, 21 showed transmission within a single team, requiring closure of that team's facilities.
• When infection rates climbed in November, the league intensified protocols, mandating high-risk interaction tracing and negative daily PCR testing, among other social rules.

Reality check: The CDC says intensive testing and contact tracing helps prevent the spread of COVID-19, but the model set by the football league could be too costly for other industries to copy.

• The NFL was reportedly willing to spend $75 million on testing alone.

What to watch: Only the Super Bowl remains, where Kansas City Chiefs and the Tampa Bay Buccaneers will play on Feb. 7 in Tampa with a limited crowd of about 22,000 fans.

• The league announced Monday it will give away 7,500 tickets to vaccinated health care workers.