Evidence that discharges from hospital were the main cause of virus outbreaks in care homes is ‘weak’, according to the UK government’s key scientific advisory group.

Instead there are ‘multiple’ routes of entry into care homes, spread across visitors, staff, hospital discharges and admission from community.

Notably a Scientific Advisory Group for Emergencies (SAGE) report suggest visitors are not the main risk but warns introduction of the virus into homes can be ‘devastating’.

The findings were echoed by doctors and public health experts, with Dr Lewis Morrison of BMA Scotland saying outbreaks in care homes were “complex and multi-factorial” and likely to be different for each care facility.

He said: “The most recent outbreaks emphasise the ongoing need for caution as covid-19 cases rise again, and that all relevant guidance must be followed for new admissions to care homes and existing residents.”

The SAGE document, from the 23^rd September, notes there are still ‘key outstanding questions’ about how the virus gets into care homes but claims:

‘The weight of evidence is stronger in some areas than others, however. Evidence of staff to staff transmission has emerged in the genomic analysis (high confidence).

‘Weak evidence on hospital discharge and modelling the impact of visitors…does not suggest a dominant causal link to outbreaks from these sources.’

Hugh Pennington, emeritus professor of bacteriology at the University of Aberdeen, warned that asymptomatic individuals were a key transmission route and failing to test people without symptoms was a ‘bad idea’.

Professor Pennington, who has chaired inquiries into E. coli outbreaks in Scotland and Wales, said more research was needed to fully understand why care homes were hit hard by the virus.

“More information about how the virus got (and continues to get) into care homes is needed to draw firm conclusions,” he said.

“Looking at two papers used by SAGE analysing results from big studies on infections in English care homes, important conclusions are the strong evidence of multiple routes of ingress of virus to many of them, and the importance of transmission by asymptomatic individuals.

He added: “Restricting testing to those with symptoms is a bad idea.”

Care homes accounted for nearly half of all covid-19 deaths in Scotland during the first spike of the virus.

A ‘significant’ outbreak at a West Lothian care home led to seven deaths earlier this week.

The Scottish government faced criticism after it was revealed that hospital patients had been discharged to care homes after testing positive for covid-19.

Nearly 40 patients were transferred in this way in five health boards, though the true figure is likely to be much higher as not all boards responded to a request for information.

Restrictions on relatives visiting care home residents have been eased after campaigning by family members.

However the paper considered by SAGE on 23^rd September suggests visiting only has a ‘marginal’ increase in covid cases in care homes.

It also states there is no ‘robust process’ to understand how isolation affects people in care homes.

SAGE is made up of UK experts who produce advice and recommendations for the UK and devolved governments.

Another paper published by the group on 17^th September says assessing different interventions says prohibiting visitors to care homes and hospitals has a “low” impact on transmission as ‘most introduction [in] care homes is probably via staff’.

Scottish Care said: “Even that this stage of the pandemic, seven months in, we are still learning and developing our knowledge of the virus. This work also underlines the importance of treating each situation as a unique context.  

“We note that that research indicates that the risk of allowing visiting to care homes has a marginal impact, and  we would be keen for further work to be undertaken on this as well as the role of asymptomatic presentation amongst staff. 

“As we move into this next phase of the pandemic, we would particularly welcome additional work to understand the impact of isolation on individuals.”