The Queen, who has been suffering from the symptoms of gastroenteritis, has cancelled the rest of her public engagements this week but will still be carrying out her official duties within Buckingham Palace.
She was due to visit London's Tech City on Wednesday and attend a chapel service on Thursday but other members of the Royal Family will now take her place.
The Palace said in a statement: "The Queen continues to make a good recovery following her recent illness, and today she presented the Queen's Gold Medal for Poetry and held a series of audiences.
"However, regrettably, she will no longer attend the Tech City engagement planned for tomorrow, or the Soldiers' and Airmen's Scriptures Association Service at the Guards Chapel on Thursday. The Duke of York will represent The Queen at the Tech City visit, and The Duke of Edinburgh will attend the Guards Chapel Service as planned.
"Her Majesty will, however, continue with the usual rhythm of business at Buckingham Palace, including holding a Privy Council meeting tomorrow. The Queen hopes to resume her programme of official engagements next week."
The Queen's trip to the East End where the Tech City firms are based was in doubt after she was forced to cancel an appearance at a major Commonwealth service on Monday - for the first time in 20 years.
Buckingham Palace gave some details about the Queen's health yesterday when a spokeswoman said: "This time last week she was in hospital but she's in great spirits and apart from this is in good health and will be going to the reception in the evening. It's just the tail end of the symptoms, her condition has not worsened at all."
On Monday night she made her first official public appearance in more than a week to sign the Commonwealth's new charter. The event was an important moment in the history of the family of nations so it appears the Queen may have felt the need to attend despite not being in full health.
But she looked relaxed, and smiled and chatted to the many guests at Marlborough House in central London where the ceremony was staged and did not appear to be in discomfort.
The 86-year-old was struck down by the symptoms of the stomach bug just over a week ago and spent last Sunday night at the private King Edward VII's Hospital in central London being assessed before being discharged on Monday.