Palace sources say the diagnosis she initially received in November has not changed and she needs time to rest and recover fully, which is more challenging with the back-to-back nature of engagements on a state visit.
The engagements changed for the state visit would have involved the Queen spending a considerable amount of time outside or standing and greeting people.
The Queen contracted the illness a month ago after a trip with the King to Australia and Samoa, which included a stopover in India on the way back.
Announcing the infection in early November, Buckingham Palace said: “Her Majesty The Queen is currently unwell with a chest infection, for which her doctors have advised a short period of rest.”
She pulled out of a number of scheduled engagements at the start of November – such as Remembrance Sunday, because of the chest infection and doctors had advised she spend a short period of rest at home.
The Palace said she would return to public duties later that month but with some changes to her schedule.
She appeared at an event at the University of London in November, where she was presented with an honorary doctorate of literature by Princess Anne.
The Queen did not attend the Royal Variety Performance with the King on 22 November after the Palace announced she would not be joining him following “lingering post-viral” symptoms from the chest infection.
