A loss or changed sense of smell or taste are to be added to the official list of symptoms for coronavirus infection, the government will announce today - weeks after concerns were raised that cases were being missed because these symptoms were being dismissed.
Deputy chief medical officer professor Jonathan Van Tam said the addition would mean identifying up to 2 per cent more cases of the virus in the community.
The formal definition of symptoms will now include whether a person has a continuous cough, fever or anosmia – the loss of smell which can also mean loss of taste. Anyone with this symptom should isolate for seven days while other household members should isolate for 14 days.
Adding anosmia to the list of symptoms could be a crucial move as the government looks to set up a test, track and isolate system to control the virus after lockdown restrictions are lifted.
But officials have faced criticism that the addition of loss of smell has come too late.
Professor Tim Spector, head of the department of genetic epidemiology and leader of the Covid symptom study app at King's College London, told the BBC Radio 4's Today programme that 17 other countries including the US had altered their list of symptoms beyond a cough and fever.
While the KCL app uses self-reported symptoms that are not verified, Prof Spector said using its data he estimated between 50,000 to 70,000 people in the UK with Covid-19 were not being told to self-isolate because their symptoms did not match the official definition.
He said: “We list about 14 symptoms which we know are related to having a positive swab test, and these are not being picked up by the NHS."
The loss of smell and taste has been repeatedly reported as a symptom of Covid-19. Health minister Nadine Dorries reported losing 100 per cent of her taste and smell when she contracted the virus in March.
Last week, the British Rhinological Society and ENT UK criticised the government for being slow to act. In a joint statement, the two bodies said they had warned eight weeks ago that anosmia was linked to Covid-19, adding that there was now “overwhelming evidence” it was a main symptom and accused the NHS and health officials of “clinical negligence” for not adding anosmia to the official list of symptoms.
Briefing journalists this morning, deputy chief medical officer Jonathan Van Tam said the government’s scientific advisers on its new and emerging respiratory virus threats advisory group, or NERVTAG, had carried out a “granular” assessment of Public Health England’s database of the first few hundred Covid-19 cases.
He said: “The reason for making the change now is that there has been a signal around possibly the importance of the anosmia as a symptom of Covid-19 for a while now. It's been important to continue to look at that. And be sure that we consider it, and introduce it at the right time, when we think it's going to make a difference moving forward, to how we pick up cases.
"We do know of some cases where it appears early, but in many cases, it does not appear early."
He added: "The question for NERVTAG has always been at what point can we be sure that by adding anosmia, or anything else, such fatigue, diarrhea, loss of appetite, definitely improve and help us to pick up cases. That work has now been completed and that's why we've got to the position we have now. It's not just about whether or not anosmia exists. It's about what role it plays in identifying cases, and that's taken time to work through those data."
He said while anosmia could last for many weeks, no one would need to isolate longer than the official advice of seven days.