Queen Elizabeth II tested positive for COVID-19 on Sunday and has mild, cold-like symptoms, Buckingham Palace said.
The palace said the 95-year-old British monarch will continue his light duties at Windsor Castle over the coming week.
“She will continue to receive medical attention and will follow all appropriate guidelines,” the palace said in a statement.
The Queen received three injections of the coronavirus vaccine.
Her eldest son, Prince Charles, and daughter-in-law, Camilla, Duchess of Cornwall, also recently contracted COVID-19. Charles has since returned to work.
Britain’s longest-reigning monarch, the Queen marked 70 years on the throne on February 6.