A member of the Queen's Buckingham Palace staff has tested positive for Covid-19 with the case being confirmed while Her Majesty was in residence at the palace, UK media have reported.
The Queen, 93, left the palace late last week after the diagnosis, moving to Windsor Castle where she remains, reportedly in good health.
The unnamed aide fell ill earlier last week and then tested positive for the virus.
Every member of the palace's staff they came into contact with has since been placed in self-isolation, the Sun reported.
It was not known what contact, if any, the worker had with the Queen.
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"The worker tested positive before the Queen left for Windsor. But the palace has 500 members of staff so, like any workplace, it's not inconceivable it would be affected in some stage," a source told The Sun.
The staffer is understood to be recovering.
"We wouldn't comment on individual members of staff," a palace spokesman told the Sun.
"In line with the appropriate guidance and our own processes, we have taken the necessary actions to protect all employees and people involved."
The Queen is set to address the United Kingdom in a televised message designed to steady the nation's nerves as it deals with a lockdown situation and rising death toll from the virus.
In the UK, panic buying continues, but the focus is moving away from toilet paper. Prime Minister Boris Johnson has ordered the closure of all pubs and bars supermarkets and liquor stores quickly sold out of alcohol.