Luton's trip to Reading this weekend has been postponed due to a Covid-19 outbreak in the Royals squad.
A statement on the official Reading website said: "We are very disappointed to announce that this weekend’s Sky Bet Championship fixture between Reading Football Club and Luton Town has been suspended.
"The club informed the EFL this morning that, following the return of a significant number of positive PCR tests within our first team and Under-23 squads, we are unable to field a team capable of fulfilling the fixture on Saturday.
"In light of the increased rate of transmissions from the Omicron variant of COVID-19, the EFL will review the circumstances surrounding the postponement and work with affected clubs to assist them throughout this challenging period.
"A rearranged date for the fixture will be announced in due course.
"We apologise unreservedly for the inconvenience and disappointment this causes to both home and away supporters, who were understandably looking forward to attending this fixture.
"However, the health, safety and welfare of our players, coaching team and club staff remains of paramount importance and our primary concern now is to ensure the swift and full recovery of those affected.
"We aim to reschedule our 150th birthday celebration event to a home fixture against Coventry City in February, marking the anniversary of our first competitive fixture in 1872.
"We will update supporters with further information on a rescheduled date for the Luton (h) fixture as soon as it is possible."
The Hatters also had an official statement which said: "Away tickets for Saturday's game will become invalid for any rearranged match.
"The Ticket Office will action a full refund for your ticket price on Friday 17th December.
"Please allow a minimum of five working days for this refund to be received.
"We would like to wish those affected at Reading a full and speedy recovery."