The Queen opted to wear long white gloves as she carried out an investiture at Buckingham Palace.
The palace declined to confirm whether the 93-year-old monarch was taking the precaution because of the coronavirus outbreak.
But the number of people diagnosed with Covid-19 in the UK has risen to 51, and the head of the World Health Organisation has advised people over the age of 60 to avoid crowded areas.
A palace spokesman said: “It is not unusual for the Queen to wear gloves on a public engagement.”
It is believed it could be the first time the monarch has done so at a palace investiture. She has not been pictured wearing gloves at a ballroom investiture in the last decade.
She wore gloves for the investiture of the Prince of Wales in 1969, but that was a high-profile, televised, open-air ceremony for her eldest son at Caernarfon Castle.
Joe Little, managing editor of Majesty magazine, said: “The Queen doesn’t wear gloves at investitures, but it’s a sensible precaution.
“She’s six or so weeks away from her 94th birthday and she’s at an age when she’s susceptible to such a virus.
“The other alternative would have been to have cancelled the investiture but the Queen is a ‘business-as-usual-monarch’.”
The death rate for people infected with coronavirus is “significantly ramped up” among people over the age of 80, England’s chief medical officer Professor Chris Whitty has said.
Meanwhile, the Prince of Wales shook hands, without gloves, as he gave out honours at the Royal College of Music’s annual awards ceremony in London, and the Duke and Duchess of Cambridge went bare-handed as they arrived for an official tour of Ireland.
A royal source said the Queen would be following any advice from the Government.
The head of state usually hands out the honours without gloves, as she carries out the fiddly task of fastening the awards to a hook on the recipients’ lapels.
The oversized gloves, which stretched past the Queen’s wrist, appeared much longer than the ones she usually wears when out and about meeting the public on official engagements.
The Queen is a fan of black or white gloves, but the end of the accessory is usually tucked into the sleeve of her coat or jacket.
Each investiture, held in the palace ballroom, is attended by more than 60 people, receiving a range of accolades, from MBEs to knighthoods and damehoods, plus their guests.
The Queen greets each recipient in turn on the low red dais and shakes their hand.
Around the world, people are rejecting handshakes and refusing kisses in an attempt to reduce the spread of the disease.
And a video has been widely shared showing people in China tapping their feet against one another – dubbed the “Wuhan Shake” – as a hands-free greeting.
Prime Minister Boris Johnson has said he will continue to shake hands with people despite the outbreak of coronavirus.
PMs usually have an audience with the Queen each Wednesday, where they typically shake the monarch’s hand.
It is not yet known whether the coronavirus will end up impacting upon key events in the royal calendar, such as sporting gatherings like Royal Ascot or the Queen’s garden parties.
More than 8,000 guests at a time mingle on the lawns of Buckingham Palace in London or at the Palace of Holyroodhouse in Edinburgh.
The monarch welcomes over 30,000 people to garden parties every year.
Although the event is outdoors, guests queue in tea tents and take their seats in nearby chairs, with around 27,000 cups of tea, 20,000 sandwiches and 20,000 slices of cake consumed at each party.
According to protocol, the Queen and fellow royals are introduced to selected guests as they make their way down the divided lanes of people, among the crowds.
Buckingham Palace declined to comment on the prospect of the summer garden parties being cancelled.