169 people who have tested positive for coronavirus in England have also tested positive for flu, meaning they have both viruses at the same time.
According to the Daily Mail, health leaders say the actual number of people who have so-called flurona - a combination of both illness - could be much higher.
They say almost a third of people who need intensive oxygen treatment because of Covid also have a second infection at the same time.
Flurona has now been found across Europe and in the USA.
Experts have predicted that flu alone could kill 60,000 people in this country in 2022, up from the usual 10,000 to 25,000.
The flurona figures from the UK Health and Security Agency only go up to October 24 - before the start of the latest wave of Covid caused by the Omicron variant.
And many people are not tested for flu as tests for the virus are not as commonly available as those for Covid.
In 2020 Public Health England said those who catch flu and Covid at the same time are twice as likely to die.
Dr Simon Clarke, a microbiologist based at Reading University, told MailOnline: "Contracting both viruses simultaneously increases the risk of being seriously ill, but risks can be mitigated by getting vaccinated and boosted against both diseases."
He added: "I would be surprised if the current number of flu and Covid co-infections was below a thousand."
