Covid Scotland: One in four 'Covid' hospital patients were not admitted because of the virus

In April, the figure dipped to a low of 66%. 

PHS stated: "As the population is increasingly vaccinated more of the patients in hospital will be fully or partially vaccinated.

"Therefore, it is important that we can differentiate between patients in hospital because of COVID-19 rather than with COVID-19, to inform Scotland’s public health response."

Hospital Covid patients are defined in three ways: people who tested positive for Covid on a PCR test up to 14 days prior to admission; patients who tested positive on the day of admission into hospital; or patients who test positive during their stay in hospital - some of whom will have contracted the infection as an inpatient. 

This can include young children and teenagers who are more likely to become infected due to lack of vaccination, but are much less likely to be seriously ill from Covid so may be in hospital for unrelated treatments. 

Of the 266 patients who tested positive for Covid in hospital in the week ending September 26, 28% were probably or definitely infected while in hospital

The PHS analysis uses data from six health boards who had "good quality and complete data" up to the end of July: NHS Ayrshire & Arran, NHS Dumfries & Galloway, NHS Grampian, NHS Greater Glasgow & Clyde, NHS Lothian and NHS Tayside.

This is "used as a proxy to represent the Scotland position", said PHS. 

The proportion of Covid patients in hospital "because of" the disease were identified through clinical diagnosis information held in Scottish Morbidity Records, a national database of acute inpatient and day case activity. 

A hospital admission ‘because of’ Covid-19 was defined as an admission where Covid-19 is recorded as the main diagnosis.

The data also shows that the average length of stay in hospital for patients there "because of" Covid fell from 13 days in January to fewer than six by July. 

This reduction is most likely linked to the roll out of the vaccination programme and the change in the age profile of patients being admitted, with Covid admissions for under-25s actually outnumbering over-75s in some weeks over the summer.  

Patients aged 18 to 29 with a primary diagnosis of Covid spent three days on average in hospital in July, compared to more than nine for those over 80. 

More recently, however, there is evidence that admissions among the over-80s and those aged 75 to 79 - the first age groups to be vaccinated - have started to climb.

For other age groups, admissions are still falling or level.  

In the latest week, 55% of hospital admissions were in patients aged 65-plus, and 23% were in patients aged 80 and over. 

It comes amid pressure to roll out booster jags to those more at risk from the virus and who may also now be experiencing a waning in their immunity against infection and, possibly, more serious illness. 

The shift in the demographics of patients admitted to hospital with Covid is also linked to a rise in the infection-to-hospitalisation conversion, which has doubled since the end of June. 

Although much lower than the peak of 12% at the end of January, the proportion of known Covid infections which lead to a hospital admissions within 14 days has doubled from 2% at the end of June to 4% by early October - and has been climbing steadily since August.