Outcomes of SARS-CoV-2 Omicron infection in residents of Long-Term Care

Background Recently there has been a rapid, global increase in SARS-CoV-2 infections associated with the Omicron variant (B.1.1.529). Although severity of Omicron cases may be reduced, the scale of infection suggests hospital admissions and deaths may be substantial. Definitive conclusions about disease severity require evidence from populations with the greatest risk of severe outcomes, such as residents of Long-Term Care Facilities (LTCFs). Methods We used a cohort study to compare the risk of hospital admission or death in LTCF residents in England who had tested positive for SARS-CoV-2 in the period shortly before Omicron emerged (Delta dominant) and the Omicron-dominant period, adjusting for age, sex, vaccine type, and booster vaccination. Variants were confirmed by sequencing or spike-gene status in a subset. Results Risk of hospital admission was markedly lower in 1241 residents infected in the Omicron-period (4.01% hospitalised, 95% CI: 2.87-5.59) compared to 398 residents infected in the pre-Omicron period (10.8% hospitalised, 95% CI: 8.13-14.29, adjusted Hazard Ratio 0.50, 95% CI: 0.29-0.87, p=0.014); findings were similar in residents with confirmed variant. No residents with previous infection were hospitalised in either period. Mortality was lower in the Omicron versus the pre-Omicron period, (p<0.0001). Conclusions Risk of severe outcomes in LTCF residents with the SARS-CoV-2 Omicron variant was substantially lower than that seen for previous variants. This suggests the current wave of Omicron infections is unlikely to lead to a major surge in severe disease in LTCF populations with high levels of vaccine coverage and/or natural immunity. Trial Registration Number ISRCTN 14447421 ### Competing Interest Statement LS and TP report grants from the Department of Health and Social Care during the conduct of the study and LS is a member of the Social Care Working Group, which reports to the Scientific Advisory Group for Emergencies. AIS and VB are employed by the Department of Health and Social Care who funded the study. AH reports funding from the Covid Core Studies Programme and is a member of the New and Emerging Respiratory Virus Threats Advisory Group at the Department of Health and Environmental Modelling Group of the Scientific Advisory Group for Emergencies. All other authors declare no competing interests. ### Clinical Protocols ### Funding Statement This work is independent research funded by the Department of Health and Social Care (COVID-19 surveillance studies). MK is funded by a Wellcome Trust Clinical PhD Fellowship (222907/Z/21/Z). LS is funded by a National Institute for Health Research Clinician Scientist Award (CS-2016-007). AH is supported by Health Data Research UK (LOND1), which is funded by the UK Medical Research Council, Engineering and Physical Sciences Research Council, Economic and Social Research Council, Department of Health and Social Care (England), Chief Scientist Office of the Scottish Government Health and Social Care Directorates, Health and Social Care Research and Development Division (Welsh Government), Public Health Agency (Northern Ireland), British Heart Foundation, and Wellcome Trust. COG-UK is supported by funding from the Medical Research Council (MRC) part of UK Research & Innovation (UKRI), the National Institute of Health Research (NIHR) [grant code: MC\_PC\_19027], and Genome Research Limited, operating as the Wellcome Sanger Institute. The views expressed in this publication are those of the authors and not necessarily those of the NHS, Public Health England, or the Department of Health and Social Care. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Research ethical approval for the study was granted by the South Central Hampshire B NHS REC ref: 20/SC/0238 I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes De-identified test results and limited meta-data will be made available for use by researchers in future studies, subject to appropriate research ethical approvals, once the VIVALDI study cohort has been finalised De-identified test results and limited meta-data will be made available for use by researchers in future studies, subject to appropriate research ethical approvals, once the VIVALDI study cohort has been finalised