With the pandemic showing no signs of slowing down — and with 37 players landing on the COVID reserve list on Monday — the NFL is taking more steps aimed at slowing the spread of the virus.

In a memo sent Monday to all teams, a copy of which PFT has obtained, the NFL explained that all Tier 1 and Tier 2 employees must receive a booster shot by December 27.

Specifically, a booster is needed for anyone who is six months removed from the second Pfizer/Moderna vaccination and two months from the Johnson and Johnson vaccinate.