A surge in Covid-19 cases driven by the Omicron variant is causing disruption to sporting events around the world.
Here's an overview of all the events affected this month:
- FOOTBALL: Crystal Palace manager Patrick Vieira tests positive for Covid hours before their away match at Tottenham.
- FOOTBALL: Hull City v Blackburn on 26 December becomes the latest EFL game to be postponed, while West Brom v Preston on 30 December was also called off.
- FOOTBALL: Aston Villa v Leeds on 28 December is postponed.
- FOOTBALL: Arsenal v Wolves on 28 December called off.
- RUGBY UNION: Newcastle's Premiership match against Sale on 26 December has been cancelled because of an outbreak of Covid cases among the Sharks squad.
- RUGBY UNION: Positive Covid cases in the Cardiff squad has caused the postponement of their United Rugby Championship game against Scarlets on 26 December.
- FOOTBALL: Championship game between Luton and Bristol City, scheduled for 26 December, called off on Christmas Day because of Covid cases in the Hatters' squad.
- FOOTBALL: Carlisle's League Two game with Rochdale at Brunton Park has been called off because of a Covid-19 outbreak in the home side's squad.
- FOOTBALL: Premier League game between Burnley and Everton on 26 December is called off because of Covid cases and injuries in the Toffees squad.
- FOOTBALL: Swansea City's Championship match against Luton, which was due to be on 29 December, has been called off because of Covid-19 cases in the Swans squad.
- RUGBY UNION: The United Rugby Championship match between Ulster and Connacht on 26 December has been postponed because of a number of positive Covid-19 cases within the Ulster squad.
- FOOTBALL: The Premier League announces it has postponed Liverpool's game against Leeds United and the match between Wolves and Watford. More EFL matches are also off.
- FOOTBALL: The Scottish Premiership winter break is brought forward from 4 January and will begin after fixtures on 26 December.
- ALL SPORT: Outdoor events in Scotland limited to 500 people, meaning most festive sport will be "effectively spectator-free".
- FOOTBALL: Three Championship games on 26 December and eight more in the EFL are called off.
- RUGBY UNION: The United Rugby Championship game between Munster and Leinster on 26 December is postponed because of Leinster's Covid cases.
- ALL SPORT: Festive sport in Wales, including horse racing's Welsh Grand National, to be held behind closed doors.
- FOOTBALL: Cardiff's home game against Coventry and Stoke's trip to Barnsley are both postponed in the Championship plus five scheduled matches in League Two are called off.
- FOOTBALL: The Premier League and EFL chose to fulfil festive fixtures rather than introduce a 'circuit breaker' despite ongoing disruption caused by Covid-19 cases.
- FOOTBALL: Premier League says there were a record 90 new positive Covid cases from tests on players and staff between 13 and 19 December.
- RUGBY UNION: The United Rugby Championship match between Ospreys and Dragons scheduled for 26 December is called off because of Covid-19 cases.
- TENNIS: Rafael Nadal tests positive for Covid-19 after returning home from the Mubadala World Tennis Championship in Abu Dhabi.
- BASKETBALL: The NBA postpones five games due to take place between 19 and 21 December, including two matches involving Brooklyn Nets.
- FOOTBALL: Aston Villa's Premier League game against Burnley, due to be played on 18 December, is postponed.
- FOOTBALL: Arsenal's Women's Super League game against Brighton, due to be played on 19 December, is postponed.
- RUGBY UNION: Sale's match with Saracens in the Premier 15s, due to be played on 19 December, is called off after the visitors reported a number of Covid-19 cases.
- AMERICAN FOOTBALL: The NFL postpones Cleveland Browns-Las Vegas Raiders, Seattle Seahawks-Los Angeles Rams and Washington Football Team-Philadelphia Eagles.
- FOOTBALL: Manchester City's WSL game against Reading and Chelsea's match against West Ham, both due to be played on 19 December, are postponed.
- FOOTBALL: 19 fixtures across the three divisions of the English Football League due to be played on 18 December are postponed.
- RUGBY UNION: Seven European matches due to be played between French and British teams this weekend are postponed because of France's new travel rules.
- TENNIS: The Battle of the Brits - an exhibition organised by Jamie Murray and featuring Andy Murray scheduled for 21 and 22 December - is postponed.
- CRICKET: Australia Test captain Pat Cummins is ruled out of the second Ashes Test against England after being deemed a close contact to a positive case.
- CRICKET: Three-match one-day series between Pakistan and West Indies, due to begin on 18 December, postponed until June 2022.
- FOOTBALL: Leicester's home Premier League match against Tottenham is postponed.
- FOOTBALL: Manchester United's home match with Brighton on Saturday is postponed.
- FOOTBALL: Wales captain Gareth Bale is among a group of Real Madrid players to test positive.
- FOOTBALL: Games postponed across all three divisions of the EFL, which announces tighter protocols and more regular testing.
- FOOTBALL: Four more Premier League games are postponed, meaning half of the weekend's fixtures are off.
- FOOTBALL: Chelsea boss Emma Hayes says the "worry and anxiety" of Covid-19 cases in her squad "played a major part" in their Women's Champions League defeat by Wolfsburg.
- RUGBY: Montpellier awarded 28-0 win for Friday's scheduled Champions Cup game because of Leinster's Covid cases.
- FORMULA 1: Ferrari driver Charles Leclerc tests positive for a second time.
- BASKETBALL: The National Basketball Association is to introduce stricter coronavirus protocols over the Christmas and New Year period as teams are left depleted by rising cases in North America.
- FOOTBALL: Burnley's Premier League match with Watford is called off three hours before kick-off after an outbreak in the Hornets squad.
- FOOTBALL: Leicester City's home game against Manchester City in the Women's Continental League Cup is postponed.
- FOOTBALL: Saturday's Championship matches between Reading v Luton and Millwall v Preston are postponed.
- RUGBY UNION: Saracens call off Saturday's European Challenge Cup game against Pau, with all players, coaches and support staff going into isolation.
- ALL SPORT: 'Covid passes' are introduced in England for any event with more than 10,000 people.
- FOOTBALL: Premier League reports 42 positive tests - the most recorded in the league over a seven-day period.
- FOOTBALL: Manchester United postpone Premier League match against Brentford.
- FOOTBALL: Manchester United shut down their Carrington training ground after a Covid-19 outbreak.
- TENNIS: Britain's Emma Raducanu tests positive and withdraws from the Mubadala World Tennis Championships.
- FOOTBALL: Sheffield United's Championship game with Queens Park Rangers is postponed because of an outbreak at QPR.
- RUGBY UNION: Three Leinster players and a member of staff test positive before the side's Heineken Champions Cup win over Bath.