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People who lose or detect a change in their normal sense of smell will now be asked to self-isolate with suspected coronavirus as the government expands the list of officially recognised symptoms.

Deputy chief medical officer Jonathan Van-Tam said the government is adding anosmia to the existing list of a new continuous cough or a fever.

Anosmia is defined as a “loss of, or a change in, your normal sense of smell”.

But the government will also explain that a loss of taste could be indicative of anosmia, he told reporters.

Van-Tam said: “In terms of public messaging we do understand that smell and taste are very closely linked in a neurological sense and that patients who experience loss of sense and smell can also experience loss of sense of taste, these two being very linked.

“Therefore from that perspective, the messaging will explain that to the public.”

People will now be asked to self isolate if they have a “new continuous cough or fever or anosmia”.

Lots of other symptoms exist, including diarrhoea and abdominal pain, but Van Tam said the government was attempting to identify specific symptoms that “make the interception of cases better”.

“We are looking for things that are not so common, [not] so non-specific that they would actually cause more confusion than clarity.”

Van Tam acknowledged that anosmia has been a suspected Covid-19 symptom for “a while now”,

But the government believes it is introducing the new official symptom “at the right time, when we think it’s going to make a difference moving forwards to how we pick up cases”. 

He stressed that working out whether anosmia is a symptom has been a “difficult piece of science”.

But the government’s new and emerging respiratory virus threats advisory group (Nervtag) has been monitoring the situation for a while and has now come to this conclusion as it gathered more data on early cases.

It is hoped that adding the symptom will help the government better monitor and control the spread of coronavirus as the infection rate and number of cases decreases, and a test and trace system is introduced.

“At a time when disease activities are going to be lower in the UK for, we hope, the foreseeable few months, it’s going to be even more important to keep it that way by picking up  all the cases we can,” Van-Tam said.

“Nervtag have arrived at a position where they feel that the addition of anosmia to the case definition actually materially improves things by a small amount.”

Van-Tam said new case pickup would grow by 3% – from picking up 91% of cases by counting just a cough or fever to picking up 94% of cases.

Anosmia can continue for days and weeks after someone recovers from Covid-19, but that is not a reason for them to stay at home as they are unlikely to be passing on the virus at this point, he said.

It differs from the guidance on self-isolating if you have a fever, which states that you should stay at home until symptoms have gone.

Van-Tam said there are “really quite variable” reports about the percentage of people who get anosmia, from the teens to more than 50%.

It is not clear whether anosmia affects certain groups of people more or less.

Van-Tam said there are signals that it is more frequent in women and girls but these are “minority reports” and the government is not in a position to be clear on that “at all”.

Editor’s note: The deputy chief medical officer originally stated that new case pickup would grow by 2% from picking up 91% of cases by counting just a cough or fever to picking up 93% of cases.

The Department for Health and Social Care has now corrected this, stating that new case pickup would grow by 3% – from picking up 91% of cases by counting just a cough or fever to picking up 94% of cases.