The number of people in hospital with Covid has continued to rise as new figures show that five cases of the highly-mutated 'Pirola' strain have now been detected in Scotland.

The latest statistics from Public Health Scotland show that there were 420 patients in hospital in Scotland as of September 10 who had tested positive for the infection.

This has risen steadily from 66 on July 1, and 210 on August 10.

It compares to 627 at the same point last year, but changes in how Covid patients are defined mean year-on-year comparisons are no longer reliable.

READ MORE: Vaccine rollout accelerated as new Covid variant found in Scotland 

Since May 8 this year, patients have been counted statistically as having Covid if they had tested positive during the prior 10 days. The previous cut-off was 28 days.

Similarly, since September 2022 only patients displaying possible Covid symptoms are tested.

Previously all patients were tested on admission and routinely during their stay, regardless of symptoms.

The Herald: Number of 'Covid positive' patients in hospital (NB: dotted vertical line shows change in definition to 10 days from May 8)Number of 'Covid positive' patients in hospital (NB: dotted vertical line shows change in definition to 10 days from May 8) (Image: PHS)

However, in line with standard infection control measures, any patients who do test positive have to be isolated - even if they are only mildly unwell or in hospital for other reasons.

This can cause disruption for elective care as it means fewer beds than expected will be available.

Data obtained by the Herald previously revealed that 237 wards had been closed to new admissions in the first seven months of this year - typically for around seven to 10 days - in order to contain Covid outbreaks.

This compared to 93 ward closures for all other infection control incident combined, including flu, RSV, and gastroenteritis.

READ MORE: Hundreds of hospital wards closed due to Covid outbreaks

The number of people in hospital with Covid in Scotland is now the highest since the new 10-day definition came into effect. On May 9, it was 236.

PHS also reports that a total of five cases of the BA.2.86 variant have now been identified in Scotland through genomic sequencing.

The strain - an offshoot from the Omicron BA.2 lineage - has attracted attention because it appears to have more than 30 new mutations on its spike protein.

The Herald: PHS said there was no clear dominant variant, but the detailed breakdown only goes up to August 13PHS said there was no clear dominant variant, but the detailed breakdown only goes up to August 13 (Image: PHS)

The "high number of mutations and the unknown effects this may have on transmissibility and severity" mean it is being closely monitored, and winter Covid vaccinations are now being accelerated for the most vulnerable groups such as over-75s and elderly care home residents.

The BA.2.86 strain - dubbed Pirola - has been detected in several countries around the world, with the first known case in Scotland picked up on August 26.

All five cases detected via PCR testing were found in the same health board, according to PHS - although it did not identify which health board this is.

Additional samples of BA.2.86 have been found in two other health board regions through wastewater testing.

READ MORE: 'Vaccine injured' groups invited to give evidence at UK Covid inquiry

PHS said that Covid levels in wastewater "have generally increased in recent weeks", although this surveillance only goes up to August 25.

The PHS report added that the number of confirmed Covid cases detected by PCR and lateral flow tests was 1,516 in the week ending September 10 and that this has "increased each week from a low level since the beginning of July".

Detailed sequencing data is only available up to the week beginning August 7. However, of the 266 PCR tests analysed, PHS said there was "no one dominant variant".

At that point, EG.5.1 - dubbed "Eris" - accounted for around 15% of sequenced cases, but 57% were either XBB or XBB.1.16 - also forms of Omicron.