Health experts have been told to exclude Covid-positive patients from daily case figures if they are not in hospital because of the viral infection.

Patients with appendicitis, for example, or an injury, but who happen to test positive for Covid-19, should be excluded from hospitalisation data, according to a Government letter sent to the National Public Health Emergency Team (Nphet).

Tánaiste Leo Varadkar, the minister in charge of enterprise, trade and employment, wants more accurate figures from Nphet on Covid-19 hospitalisations as the highly-infectious Delta variant is monitored.

He says people admitted with other complaints, illnesses and conditions, but who test positive for Covid-19 – often without symptoms – are being categorised as Covid-19 cases.

“There are essentially three categories and we should be able to quantify them,” he said.

“The first are those admitted with Covid and being treated for it; the second category are those admitted with something else but who got Covid in hospital and are now being treated for it, and the third are those admitted for something else, who were swabbed and found positive, but who are not being treated for it.”

Martin Fraser, secretary general at the Department of the Taoiseach, has written to Nphet seeking more detailed breakdowns to guide Government policy and to give a clearer picture of the Delta variant’s spread.

The letter suggests the daily data should only reflect people who go to hospital because of Covid-19.

Ministers privately believe at least 10pc of Covid-19 patients are unaffected by serious symptoms, with a senior Government source telling the Irish Independent: “We don’t know the actual level. It could be higher than that.”

Another said: “What the Cabinet is seeking from the HSE is better data on the number of people who are actually in hospital being treated for Covid.”

Data from other countries suggest that as many as one in seven hospital patients are Covid-19 positive, with the news coming as a shock to many as they are or were asymptomatic.

A total of 1,126 new cases of Covid-19 were reported yesterday, with 123 patients with the virus in hospital, 22 of whom are in intensive care units.

Mr Varadkar said some people were in hospital “because their appendix burst or they broke a leg, or they’re in for a knee op. It’s not that they’re being treated for Covid.

“So it is essential that we need to find out better data in terms of hospitalisations as to who is actually in hospital because they’re being treated for Covid, as opposed to who is in hospital and Covid positive, which of course is not quite the same thing.”

Elimination of non-specific Covid cases from figures has been adopted in many cases, with the World Health Organisation offering no opposition to the non-categorisation of such patients.

A senior source said: “It’s a bit of a grey area, and there could be some queries from Nphet, but essentially it’s about trying to get a sense of where we are at with acute cases.

“If we can get the figures sharpened up a bit will be all to the good so that we better know what we are dealing with as the situation continues and as hospitality opens up.”