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Nosocomial transmission of COVID-19: two new reports look at the impact of healthcare-acquired infection

Published: 13 May 2022

Two new reports from Public Health Wales have looked at the impact of nosocomial (hospital-acquired) transmission of Coronavirus during the pandemic.  They show that the proportion of deaths where Coronavirus was acquired in healthcare settings was consistent with the level in community-acquired infections.   

The first report, ‘Mortality in Nosocomial COVID-19 Cases in Wales’, looked at data from 9000 patients with nosocomial COVID-19. It found that the rate of mortality from all causes approximately one month after diagnosis (known as all-cause mortality or ACM) for those patients who caught COVID in hospital, was consistent with the rate in those patients in hospital who had caught COVID in the community – once other factors had been accounted for.   

Clearly, those patients who needed an extended period in hospital – more than a week – are more likely to have serious comorbidities, such as diabetes or other chronic conditions.  We know that the chance of dying with COVID is higher with these comorbidities.  Likewise, patients already in hospital are generally older and therefore more likely to have these comorbidities. The report uses data that takes these factors into account to give a clear picture of the impact of nosocomial transmission on ACM. 

The report shows that once these confounding factors are taken into account, there is no significant difference between the rate of mortality of those who acquired Coronavirus in hospital compared to those who caught the infection in the community and subsequently admitted to hospital. 

The second report, ‘Nosocomial COVID-19 in Wales: Lessons Learned from Hospital Outbreaks, September 2020 - April 2021’, looks at the second wave of the pandemic, and reviews the implementation of lessons learned in the first wave during the second.  It demonstrates the importance of rapid review and learning to support ongoing safe and effective care. 

The second wave was significantly more challenging for healthcare settings than the first, largely due to continuing with more comprehensive routine care in the second wave, including elective services, whereas in the first wave this was all but cancelled.  In addition, vaccinations were not widely available until later in this second wave, and there was a high level of asymptomatic transmission of Coronavirus among staff, leading to ongoing staff absences which increased pressure in an already stretched service. 

During the second wave, some patients were moved unnecessarily, which could have been linked to outbreaks.  In addition, the infrastructure of hospitals is an ongoing challenge in terms of effective infection prevention and control.  Finally, the report identifies a need to utilise data from community settings more effectively, as this can act as an ‘early warning system’ to enable hospital staff to act proactively faster, rather than responding reactively when COVID-19 cases occur. 

The report however makes clear that some lessons from the first wave were implemented as we faced the second wave.  These included an increased awareness of asymptomatic transmission of COVID, and also those who presented with atypical symptoms – both of these influenced testing protocols in hospitals on both a local and national level.   

In addition, staff were encouraged not to move between COVID and non-COVID areas, and daily symptom checks, and the arrival of Lateral Flow Devices later on in the period, allowed staff who were asymptomatic or with atypical symptoms to be identified before exposure to patients. 

The report concludes that these actions mitigated the spread of COVID in healthcare settings and this knowledge will be important in the management of future seasonal waves of COVID, or challenges presented by new variants. 

Dr Eleri Davies, Deputy Medical Director and Head of the HARP Programme for Public Health Wales, said:

“Clearly the pandemic has been an enormous challenge to staff across all health settings, and they have dealt with the many difficulties extremely well.  Nosocomial transmission of Coronavirus has unfortunately been a significant part of the overall infection picture in all countries of the UK, and these reports look at it in detail. 

“Every death from Coronavirus is a tragedy for the family, and our sympathies go to all families who have been through this awful situation.   

“The report finds that deaths where Coronavirus has been acquired in healthcare settings is consistent with those who have acquired it in community settings, once confounding factors are taken into account. 

“It is also clear that the intense pressures of the second wave made it difficult to implement all the lessons learned from the first wave.  However, it is important to note that rapid review and learning from the first wave did result in implementation of some measures that mitigated against nosocomial spread of COVID, which will have had a positive impact on our management of the second wave.”