A new study has suggested that COVID-19 care home outbreaks in England, UK, were caused by multiple independent infections as well as within care home spreading.
The research, presented at the ESCMID Conference on Coronavirus Disease (ECCVID), also shows evidence of transmission between residents and healthcare workers, including paramedics, drawing a possible link between care home outbreaks and hospital outbreaks. However, the researchers note that the direction of transmission between individuals could not be confirmed.
The researchers said: “We present a large genomic epidemiology study of care home-associated COVID-19 infections in the UK. Care home residents had a significant burden of COVID-19 infections and high mortality. Larger viral clusters suggested within care home outbreaks, while multiple clusters per care home suggested independent acquisitions. Integrated genomic and epidemiological data collected at scale can provide valuable insights into SARS-CoV-2 transmission dynamics; in future, such analyses could be used for targeting public health responses.”
The study was led by Dr William Hamilton, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK, and colleagues.
Infection control in care homes
Older people are at increased risk of having adverse reactions to COVID-19, posing major challenges for infection control in care home settings.
For the study, the researchers collected data and COVID-19 samples from patients in the East of England between 26 February and 10 May 2020. The samples were genetically sequenced at the University of Cambridge or the Wellcome Sanger Institute, and viral clusters were identified within each care home based on integrated genomic and temporal differences between cases.
A total of 7,406 positive COVID-19 samples from 6,600 patients were identified, of which 1,167 (18%) were residents from 337 different care homes. 40% of the care home residents who tested acutely at Cambridge University Hospitals NHS Foundation Trust (CUH) died.
Genetic sequences were available for 60% of the residents from 292 care homes, and 409 distinct viral clusters were defined. The largest clusters comprised more than 10 samples from the same care home, consistent with care home COVID-19 outbreaks.
The authors stated: “Care homes with multiple clusters suggested multiple independent viral acquisitions among residents. We also identified several probable transmissions between care home residents and healthcare workers, based both in the community (carers and paramedics) and the hospital, suggesting a potential link between care home-associated and healthcare-associated COVID-19 infections.”
