Seven-time Formula One world champion Lewis Hamilton will miss this weekend's Sakhir Grand Prix after testing positive for COVID-19.
Hamilton tested positive on Monday, the day after his victory at Sunday's Bahrain Grand Prix, during a mandatory PCR test for the upcoming Sakhir Grand Prix at the same circuit this weekend.
He had tested negative three times the previous week, including on Sunday afternoon ahead of the Bahrain Grand Prix, but woke up on Monday morning with mild symptoms and subsequently tested positive. He was also informed on Monday that a contact prior to his arrival in Bahrain had also tested positive.
The 35-year-old has already secured this year's drivers' title, but will miss this weekend's Sakhir Grand Prix and could also miss the season finale in Abu Dhabi the week after if he fails to return a negative test in time.
It is not yet clear who will replace Hamilton at Mercedes, who has won 11 of this year's 15 races.
Stoffel Vandoorne is listed as the team's official reserve driver and is currently testing for Mercedes' Formula E team in Valencia. He last raced in F1 for McLaren in 2018 and will travel to Bahrain later this week to join the Mercedes F1 team.
Hamilton is currently isolating in accordance with public health authority guidelines in Bahrain and his contacts have been declared to the FIA.
"The Mercedes-AMG Petronas F1 Team regrets to announce that Lewis Hamilton has tested positive for COVID-19 and will be unable to take part in this weekend's Sakhir GP," a Mercedes statement said.
"Lewis was tested three times last week and returned a negative result each time, the last of which was on Sunday afternoon at the Bahrain International Circuit as part of the standard race weekend testing programme.
"However, he woke up on Monday morning with mild symptoms and was informed at the same time that a contact prior to arrival in Bahrain had subsequently tested positive.
"Lewis therefore took a further test and returned a positive result. This has since been confirmed by a retest.
"Lewis is now isolating in accordance with COVID-19 protocols and public health authority guidelines in Bahrain. Apart from mild symptoms, he is otherwise fit and well, and the entire team sends him its very best wishes for a swift recovery.
"We will announce our replacement driver plans for this weekend in due course."
Hamilton will be the third driver to miss a race this year due to a positive COVID-19 test in a season that has been completely rescheduled due to the pandemic.
Sergio Perez sat out of the British and 70th Anniversary Grands Prix at Silverstone earlier this year and his Racing Point teammate Lance Stroll missed the Eifel Grand Prix after feeling unwell and later testing positive for COVID-19. Nico Hulkenberg substituted for both Racing Point drivers on those occasions.
Hamilton secured this year's championship at the Turkish Grand Prix in mid-November with three races remaining on the calendar. Mercedes has dominated this year's championship, taking 13 of the 15 race victories, 14 pole positions and both drivers' and constructors' world championships.