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expert reaction to first results from the Vivaldi study looking at COVID-19 infections care homes

The Vivaldi study, from the Office of National Statistics (ONS), has looked at COVID-19 infections care homes and released the first results. 


Prof Sheila Bird, former Programme Leader, MRC Biostatistics Unit, University of Cambridge, said:

“Only a brief report was issued today by Department of Health and Social Care about this swab-test surveillance in care homes for the 0ver 65s – in effect, a census but delivered over 28 days.

“The report differentiates residents from non-residents and individuals who were symptomatic versus asymptomatic.

“A key omission from the report is definition of what is meant by an individual being symptomatic. One possibility is that the symptomatic-label was applied if at least one of three key symptoms (new cough; fever; loss of taste or smell) was present. This definition may be appropriate for working age non-residents but does not include, for example, sudden-onset anorexia, which may alert to the possibility of COVID-disease in elderly care home residents.

“My table reveals that asymptomatic residents (however defined by this surveillance) account for 81% of positives amongst All Residents (5 455/6 747). Asymptomatic non-residents (ie staff) constitute the second largest concentration of swab-positives (2 567). 

“Oddly, a higher proportion of non-residents was apparently symptomatic than of elderly residents. The explanation may lie in the survey’s definition of “symptomatic”. Definitions matter always.

“Another quizzical note: “results for symptomatic staff are not available as they were not tested within the home”. If not staff, then who are the 14 551 symptomatic non-residents?

“Swab-testing is uncomfortable for elderly Residents. Hence, the current plan is for weekly testing of care home staff (the second largest contingent of swab-positives), but asymptomatic Residents will be tested only once in 4-weeks.

This plan would change dramatically if saliva testing is shown to be as or more clinically effective than nasopharyneal swabs for elderly Residents of care home.”


Total tests

Total positive


Percent Symptomatic

All who were tested

397 197

9 674




All Residents

172 066

6 747




Symptomatic Residents

8 121

1 292




163 945

5 455




All non-Residents

225 131

2 927




Symptomatic non-Residents

14 511



Asymptomatic non-Residents

(ie staff)

210 620

2 567





Professor Sarah Harper, Clore Professor of Gerontology, University of Oxford, said:

“The survey has some limitations (acknowledged by the authors) in particular it is based on care home managers recalling information on behalf of their residents and staff, and recalling events in the past. (The reference period for the study was “since 1 March 2020” and the survey took place between 26 May and 20 June 2020.) However, if anything this is likely to reduce estimates.

“The response rate was good (56%) for the voluntary sector in comparison with similar surveys, and the respondents were representative of all sizes of care homes in the sample.

“The testing part of the study found that ‘80.9% of residents who tested positive were asymptomatic (5,455 out of 6,747)’. This is an important message that given our understanding of the Covid-19 disease, we need to be careful about the general assertions around the impact of certain population characteristics – such as age for example.  Our early conclusions that younger people were generally asymptomatic, but older adults were less likely to be, has now been questioned. This survey further emphasizes that the disease is complex and its progress and impact still unclear.  There has been a general assumption in some media reports that CV19 was a death sentence for all older people – this study emphasizes that many older adults as well as younger people can have the disease mildly.

“It has long been suspected that current hospital to care homes discharge guidelines and the structure and operation of care homes, including the role of care workers,  were leading to a spread of infections in care homes and subsequently high number of fatalities. There are several pathways of hospital discharge, and we know that during this time older people were being discharged to a care home without being tested for COVID-19 at hospital prior to dispatch. Once in the care home, the infection can then be transmitted through the social care system, especially in the early days when there was a  lack of guidance to care workers and care managers and a shortage of PPE for these workers. Many of the care workers either work through agencies or have multiple roles, and  they can visit several care homes and homes in the community all on the same day, which can further spread the infection between the most vulnerable groups of the population.

“This again raises the question of the state of the social care system – which has been in desperate need of reform for years. It is underfunded and the care workers are underpaid. The study also reveals that care homes in which staff receive sick pay are less likely to have cases of COVID-19 in residents compared to those care homes where staff do not receive sick pay. If we look at other countries where care home deaths were not as high  we can see a very different system of trained respected carers, properly rewarded for their difficult work, and not reliant on multiple agency jobs to earn a living.”


Prof Keith Neal, Emeritus Professor of the Epidemiology of Infectious Diseases, University of Nottingham, said:

“Care homes have been badly affected by COVID-19 across Europe.  I am more surprised that 44% of care homes have managed to report no COVID-19 cases amongst staff or residents.

“80% of residents with COVID-19 positive tests were asymptomatic is unexpected given age being the dominant risk factor for severity.

“Keeping COVID-19 out of all care homes, and preventing spread, was always going to be a nigh on impossible task.  Infection control is not as easy as the words suggest.  It is far more than masks, gloves/hand washing and other PPE is required. 

“Even if all care staff were tested daily, a 24 hour delay in getting results would mean they had worked for one day whilst infectious. 

“Even wearing of masks continually would not guarantee safety as masks are not 100% effective.

“Testing all patients before discharge to a care home from hospital certainly helps stop spread.  But to be totally safe requires a test with 100% sensitivity and PCR is probably quite a bit lower.  Hence, infectious patients would have been discharged to care home with a negative test and be sources of spread.

“Add to that the majority of residents with infection were also asymptomatic then they would spread infection through the care home.  It is totally impractical for residents to also wear masks especially those with dementia.  Confining all residents to their rooms throughout the pandemic with no social interaction would have serious mental health impacts and impossible for residents with dementia.

“The role of staff working in multiple homes was a lesson we should have learnt from the spread of MRSA decades ago.

“Deaths in care homes are best monitored by the weekly ONS data as they get place of death and death certificate given cause for all deaths,


Dr Michael Head, Senior Research Fellow in Global Health, University of Southampton, said:

“The Vivaldi study shows clearly the devastating impact of the pandemic within care homes. Residents are always extremely vulnerable to infectious disease outbreaks, whether it be norovirus, scabies or here with COVID-19. They are often a neglected and forgotten population and deserve so much better than the lack of preparation and focus received before and during this pandemic. Infection control is much more difficult in these environments in part because these are people’s homes rather than, for example, a hospital ward.

“It is interesting to see an indication of reduced infection where there is a lower use of bank staff and where care home staff receive sick pay. These members of staff are often receiving relatively low pay, yet they are working in an incredibly difficult environment and sometimes without appropriate levels of PPE. There does need to be a conversation about how best to manage residential and nursing care during a public health emergency and that conversation needs to consider the needs of the staff.”


All our previous output on this subject can be seen at this weblink:


Declared interests

Prof Sheila Bird: SMB chairs a panel of the RSS COVID-19 Taskforce which interacts with DHSC’s statisticians on testing statistics.

None others received

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