On Friday, British Prime Minister Boris Johnson became the first major world leader to test positive for coronavirus. Johnson was last in the presence of the 93-year-old Queen Elizabeth II on March 11, the palace told USA TODAY in a statement.
Also on Friday, Buckingham Palace announced that the annual Trooping the Colour parade, the popular celebration of the queen's official birthday, will not go ahead "in its traditional form" in June.
"A number of other options are being considered, in line with relevant guidance," the palace statement said. The queen turns 94 in April, but her birthday is celebrated in June when the weather is usually better.
The celebration features ranks of marching troops and mounted guards in colorful uniforms, huge crowds on The Mall and an all-royal family spread on the palace balcony as an air force flyby concludes the festivities.
The queen’s son, Prince Charles, also tested positive for the coronavirus earlier this week and last came into contact with the queen on March 12.
"The Queen remains in good health. The Queen last saw the (prime minister) on the 11th March and is following all the appropriate advice with regards to her welfare," Buckingham Palace said in a statement Friday. The palace declined to comment on whether the queen, 93, and Prince Philip, 98, have been tested for coronavirus.
The 71-year-old Prince of Wales, the heir to the British throne, tested positive for the virus after "displaying mild symptoms," Clarence House, his official royal residence, said in a statement Wednesday.
On Friday, Clarence House confirmed the last time Charles was in the presence of Johnson was March 9.
"To confirm the last time The Prince of Wales saw the Prime Minister was at the Westminster Abbey Commonwealth service on March 9th," the statement read.
The statement from Clarence House announcing Prince Charles' positive test results noted: “It is not possible to ascertain from whom the Prince caught the virus owing to the high number of engagements he carried out in his public role during recent weeks.”
The Prince of Wales is self-isolating at Birkhall, the prince's home on the royal Balmoral estate in Scotland. His wife, Duchess Camilla of Cornwall, 72, has tested negative for the virus and is also self-isolated apart from Charles at Birkhall.
USA TODAY has reached out to Clarence House for comment.
The news of Charles and Johnson's positive coronavirus tests come a week after the queen relocated to Windsor Castle amid the pandemic.
The queen canceled a number of events "as a sensible precaution" due to the outbreak but as late as last week she was still holding "audiences" with visiting dignitaries.
On Wednesday she held her weekly audience with the prime minister by phone, according to the picture released by the palace that showed her speaking on an old-fashioned landline phone.
On March 19, Queen Elizabeth sent a message via her press office broadly addressing the coronavirus pandemic: "As Philip and I arrive at Windsor today, we know that many individuals and families across the United Kingdom, and around the world, are entering a period of great concern and uncertainty.
"We are all being advised to change our normal routines and regular patterns of life for the greater good of the communities we live in and, in particular, to protect the most vulnerable within them."
Contributing: Sara M Moniuszko, Kim Hjelmgaard, Leora Arnowitz, Maria Puente; The Associated Press