A group of 25 doctors have written to the Health Secretary, Matt Hancock, because they are concerned about the UK's current advice on self-isolation for coronavirus.
The guidance says people should stay at home and avoid contact with others for seven days if they develop symptoms.
After that, self-isolation can end - if they feel well and do not have a fever.
But World Health Organization advice says people should self-isolate for 14 days after symptoms have cleared.
And now, Newcastle University public health expert Prof Allyson Pollock and 24 similarly concerned colleagues are asking to see evidence in support of the UK's stance.
The Department of Health and Social Care says the recommendations are based on science and expert advice suggesting:
- most people will develop symptoms within five days of having contact with the virus
- after seven days, the virus is highly unlikely to be passed on to anyone else
The UK guidance says a cough may persist for several weeks despite the coronavirus infection having cleared and does not mean self-isolation should be prolonged.
Although, if symptoms worsen and especially if a person develops shortness of breath or a new fever, they should contact NHS 111.
The WHO recommendations provide a framework countries then adapt to suit their national circumstances, it adds.
An official said: "The government's response to this virus and all clinical guidance is led by science and a world renowned team of clinicians, public health experts and scientists - including epidemiologists - working round the clock to keep us safe."
But Prof Pollock and her colleagues say there have been reports of a risk of infection beyond seven days - ranging from 10 to 24 days after symptoms begin.
"We are also concerned about the narrow spectrum of symptoms the UK is using as an indication for self-isolation," they write in their letter to Mr Hancock.
The UK says cough and fever are the key ones but other common ones may include:
- sore throat
- shortness of breath
- muscle aches
"We are aware that other countries are using a broader range of symptoms for self-isolation," they add.