Facing a spike in positive tests for the coronavirus among players this week, the N.F.L. said in a memo that it would mandate booster shots among team staff who work most closely with players.
Even with a vaccination rate among players that is over 94 percent, more coronavirus cases have been reported this season in the N.F.L. compared to last year, according to a review of league data by The New York Times. The sense of urgency escalated Monday, when 37 players tested positive, the highest single-day total since the start of the pandemic.
The N.F.L. said the players’ positive tests are being driven by community spread, though the number of coronavirus cases across United States, while rising, is still below 2020 numbers.