A. Jeffery-Smith, K. Dun-Campbell, R. Janarthanan, J. Fok, E. Crawley-Boevey, A. Vusirikala, Elena Fernandez Ruiz De Olano, M. Sanchez Perez, Suzanne Tang, Thomas A. J. Rowland, E. Wynne-Evans, A. Bell, B. Patel, Z. Amin-Chowdhury, F. Aiano, K. Paranthaman, T. Ma, M. Saavedra-Campos, J. Ellis, A. Lackenby, H. Whitaker, R. Myers, K. Höschler, K. Brown, M. Ramsay, N. Shetty, J. Chow, S. Ladhani, M. Zambon
The Lancet Regional Health - Europe, 2021
Background Care homes have been disproportionately affected by the COVID-19 pandemic. We investigated the potential role of asymptomatic infection and silent transmission in London care homes that reported no cases of COVID-19 during the first wave of the pandemic. Methods Five care homes with no cases and two care homes reporting a single case of COVID-19 (non-outbreak homes) were investigated with nasal swabbing for SARS-CoV-2 RT-PCR and serology for SARS-CoV-2 antibodies five weeks later. Whole genome sequencing (WGS) was performed on RT-PCR positive samples. Serology results were compared with those of six care homes with recognised outbreaks. Findings Across seven non-outbreak homes, 718 (387 staff, 331 residents) individuals had a nasal swab and 650 (385 staff, 265 residents) had follow-up serology. Sixteen individuals (13 residents, 3 staff) in five care homes with no reported cases were RT-PCR positive (care home positivity rates, 0 to 7.6%) compared to 13 individuals (3.0 and 11.1% positivity) in two homes reporting a single case. Seropositivity across these seven homes varied between 10.7-56.5%, with four exceeding community seroprevalence in London (14.8%). Seropositivity rates for staff and residents correlated significantly (rs 0.84, [95% CI 0.51-0.95] p <0.001) across the 13 homes. WGS identified multiple introductions into some homes and silent transmission of a single lineage between staff and residents in one home. Interpretation We found high rates of asymptomatic infection and transmission even in care homes with no COVID-19 cases. The higher seropositivity rates compared to RT-PCR positivity highlights the true extent of the silent outbreak. Funding PHE
Cited by 8 publications.
Field of study: Medicine