The Queen is working on "light duties" at Windsor Castle this week despite testing positive for Covid, royal officials say.
Buckingham Palace confirmed on Sunday that the Queen, 95, was experiencing "mild cold-like symptoms".
But the Queen's medical team will likely be keeping a very close eye on her, especially as she is considerably thinner and frailer than she was last year, Daniela Relph added.
The Queen's eldest son and heir, the Prince of Wales, 73, tested positive on 10 February, two days after the pair had met each other.
A number of people have also tested positive at Windsor Castle where the Queen lives, it is understood.
The Queen had no public engagements in the diary this week, but it is likely that any scheduled video meetings are likely to have been postponed.
While on light duties it is likely the Queen will be reading documents from UK government ministers and Commonwealth representatives sent to her every day, approving and signing them where necessary.
The Queen, who will be 96 in April, had her first vaccine in January 2021 and is believed to have had all her follow-up jabs after that.