The 95-year-old is continuing with “light duties”, four days after her positive Covid test was announced.
The Queen has postponed engagements for the second time in a week following her positive Covid test.
Buckingham Palace said the monarch, who tested positive for the virus on Sunday, would continue with “light duties”.
Thursday’s virtual audiences will now take place on later date, it added.
The Queen, 95, also cancelled virtual engagements on Tuesday, but she did have her telephone audience with the prime minister on Wednesday.
A Buckingham Palace spokesman said: “The two virtual audiences that had previously been scheduled to take place today will now be rescheduled for a later date.
“Her Majesty is continuing with light duties. No other engagements are scheduled for this week.”
In a statement announcing the positive test, the Palace said the monarch was experiencing “mild cold-like symptoms”.
It is understood a number of people tested positive at Windsor Castle, where the Queen resides.
The Queen, who will be 96 in April, had her first vaccine in January 2021 and is believed to be triple-vaccinated.