The 95-year-old monarch felt well enough to speak to foreign diplomats on Tuesday, after postponing a number of similar engagements last week.
She tested positive for coronavirus on Sunday, February 20. Buckingham Palace said at the time she was experiencing “mild cold like symptoms”.
On Tuesday, Queen Elizabeth received His Excellency Mr Carles Jordana Madero, who presented the Letters of Recall of his predecessor and his own Letters of Credence as ambassador from the Principality of Andorra to the Court of St James’s.
She also received His Excellency Mr Kedella Younous Hamidi, who presented his Letters of Credence as ambassador from the Republic of Chad to the Court of St James’s.
Her Majesty had previously cancelled similar engagements while suffering “mild” Covid symptoms.
But despite this, she carried out some light duties at Windsor Castle, including her weekly telephone audience with the Prime Minister.
She has more engagements coming up this month.
The Queen is set to host the Diplomatic Reception on March 2, where she will meet hundreds of members of the Diplomatic Corps at Windsor.
The event has already been scaled back from tiara and white tie to lounge suit and cocktail dress.
She is also due to be at the Commonwealth Service at Westminster Abbey on March 14, and then the Duke of Edinburgh’s memorial service, also at the Abbey, on March 29.
The nation’s longest reigning monarch, who is thought to have been triple vaccinated, recently spent more than three months resting, on doctors’ orders.
In the autumn, she pulled out of attending the Cop26 climate change summit, the Festival of Remembrance and then the Remembrance Sunday Cenotaph service due to a sprained back. She also missed the Church of England’s General Synod.
The Queen now regularly uses a walking stick and has been pictured looking frailer recently.
She recently remarked during a Windsor Castle audience: “Well, as you can see, I can’t move.”
Her lights duties as head of state include working from her red boxes, sent to her every day and containing policy papers, Foreign Office telegrams, letters and other State papers which have to be read and, where necessary, approved and signed.
She also sent a congratulatory message to the Team GB women’s curling team after they won gold at the Beijing Winter Olympics.
The Queen has spent much of the pandemic at Windsor Castle.
Celebrations for her Platinum Jubilee, marking 70 years on the throne – a milestone that was reached on 6 February – will take place in June.