INCREASED RISK OF SARS-CoV-2 INFECTION IN STAFF WORKING ACROSS DIFFERENT CARE HOMES ENCHANCED CoVID-19 OUTBREAK INVESTIGATIONS IN LONDON CARE HOMES

Ladhani, Shamez N; Chow, J. Yimmy; Janarthanan, Roshni; Fok, Jonathan; Crawley-Boevey, Emma; Vusirikala, Amoolya; Fernandez, Elena; Perez, Marina Sanchez; Tang, Suzanne; Dun-Campbell, Kate; Evans, Edward Wynne-; Bell, Anita; Patel, Bharat; Amin-Chowdhury, Zahin; Aiano, Felicity; Paranthaman, Karthik; Ma, Thomas; Saavedra-Campos, Maria; Myers, Richard; Ellis, Joanna; Lackenby, Angie; Gopal, Robin; Patel, Monika; Chand, Meera; Brown, Kevin; Hopkins, Susan; Shetty, Nandini; Zambon, Maria; Ramsay, Mary E

BACKGROUND: Care homes have been disproportionately affected by the COVID-19 pandemic and continue to suffer large outbreaks even when community infection rates are declining, thus representing important pockets of transmission. We assessed occupational risk factors for SARS-CoV-2 infection among staff in six care homes experiencing a COVID-19 outbreak during the peak of the pandemic in London, England. METHODS: Care home staff were tested for SARS-COV-2 infection by RT-PCR and asked to report any symptoms, their contact with residents and if they worked in different care homes. Whole genome sequencing (WGS) was performed on RT-PCR positive samples. RESULTS: In total, 51 (20%) of 250 staff were SARS-CoV-2 positive but only 11/51 (22%) were symptomatic. Among staff working in a single care home, SARS-CoV-2 positivity was 15% (2/13), 16% (7/45) and 17% (28/165) in those reporting no, occasional and regular contact with residents. In contrast, staff working across different care homes (14/27, 52%) had a 4.2-fold (95% CI, 2.1-8.4; P<0.001) higher risk of SARS-CoV-2 positivity than staff working in single care homes (37/223, 17%). WGS identified SARS-CoV-2 clusters involving staff only, including some that included staff working across different care homes. CONCLUSIONS: SARS-CoV-2 positivity was significantly higher among staff working across different care homes than those who were working in the same care home. We found local clusters of SARS-CoV-2 infection between staff only, including those with minimal resident contact. Infection control should be extended for all contact, including those between staff, whilst on care home premises.