At least 10% of all COVID-19 infections in England during a 6 week period were among patient-facing healthcare workers and resident-facing social care workers, experts revealed today.
They estimated that a further 1% of infections between 26th April and 7th June were acquired by inpatients in hospital, with additional infections among care home residents thought to account for at least 6% of all infections.
The figures came from a rapid assessment of available evidence carried out by Data Evaluation and Learning for Viral Epidemics (DELVE), a multi-disciplinary group convened by The Royal Society.
The focus of the report, COVID-19 acquisition and its control in healthcare settings, was aimed at preparing health and care settings to open up for routine work ahead of the winter, and for possible future waves of COVID-19.
However, the researchers said data was limited, meaning much was still unknown about how the SARS-CoV-2 virus spread in the NHS and in care homes.
"We conclude that there are still gaps in our understanding, and particularly we haven't got granular data on the impact on black, Asian, and minority ethnic healthcare staff," said Prof Dame Anne Johnson from University College London, a member of the DELVE committee.
The report identified substantial obstacles for healthcare settings trying to re-establish normal working patterns during the pandemic. It said one recent modelling study estimated that 20% of inpatient infections, and up to 89% of healthcare worker infections, had been hospital-acquired.
Asymptomatic or mildly symptomatic healthcare workers posed an unrecognised transmission risk to others in the hospital and in the community, and may have contributed to the number of cases in these settings.
Inadequate personal protective equipment (PPE), a lack of testing capacity, not separating patients with the disease and those without, and staff not always observing social distancing, may have partly been responsible for the spread of the disease, the experts suggested.
According to DELVE, systematic data collection on COVID-19 has been insufficient to identify sources and risks for hospital-acquired transmission, and to allow effective targeted outbreak response and infection control.
Despite a paucity of data, healthcare worker COVID-19 prevalence was estimated to be nearly six times higher than in the general population in England based on PCR testing, the report noted.
It pointed to limited exploration of the extent to which infections acquired within hospitals boosted spread in the community, including to and from care homes.
Dr Nigel Field, chair of the DELVE working group, told a briefing convened by the Science Media Centre, that "insufficient surveillance system[s] will mean that you cannot identify new infections rapidly, conduct thorough investigations on outbreaks to identify where the sources of infection are, and change things".
The DELVE report makes a number of recommendations. These included:
Rapid identification of COVID-19 cases within hospitals
Centralised surveillance and monitoring of Covid-19 infections acquired within hospitals
Connected COVID-19 data systems across community, care institutions, and hospitals
Standardised, tiered infection prevention and control guidelines
Regional or local outbreak investigations for COVID-19
Data obtained from surveillance, monitoring, and outbreak investigations should feed into epidemiological and modelling research and evaluation
Prof Johnson, who is vice-president of the Academy of Medical Sciences, said once it was possible to get on top of the epidemic, "it will help put out the fires, or put out the spark, so we don't get the fires going forward".
She said: "We've got a window of opportunity now to get everything in place, and to try also to be ready for winter."