Leicester's Boxing Day Premiership game at Newcastle has been called off following positive Covid tests in the Tigers squad.
Only several positive tests were returned but a large number now need to self-isolate due to contact tracing.
Premiership Rugby issued a statement to confirm that the game is now cancelled.
"Neither Premiership Rugby nor the club will be naming any of the players or staff involved and we'd ask everyone to respect their privacy," it said.
"Our priority is the health and safety of everyone involved with Leicester Tigers and Newcastle Falcons. We will give the clubs any support they need."
Premiership Rugby will make a further announcement on the allocation of points for the fixture when a panel has been convened.
But, following a rule change in November, the Premiership said that they will no longer automatically award five points to teams when the opposition is unable to field a side because of coronavirus.
Instead, a four-point win is awarded to the club able to name a side, with two points to the team forced to cancel.
This is the first Premiership cancellation since the new season began, although several games have been called off in the two European trophies.
On the final day of the regular 2019-20 Premiership season, Sale were unable to play because of positive Covid test results and their match with Worcester was eventually cancelled.
Warriors were given a 20-0 win and five points as Sale missed out on the play-offs.
Leicester were due to return to Premiership action after two rounds of European Challenge Cup action which brought wins over French clubs Brive and Bayonne.
The complete cancellation, rather than postponement, of the game maintains promoted Newcastle's unbeaten start to the new league season.