Relation of severe COVID-19 in Scotland to transmission-related factors and risk conditions eligible for shielding support: REACT-SCOT case-control study

McKeigue, P. M. et al. (2021) Relation of severe COVID-19 in Scotland to transmission-related factors and risk conditions eligible for shielding support: REACT-SCOT case-control study. BMC Medicine, 19, 149. (doi: 10.1186/s12916-021-02021-5) (PMID:34158021) (PMCID:PMC8219469)

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Abstract

Background: Clinically vulnerable individuals have been advised to shield themselves during the COVID-19 epidemic. The objectives of this study were to investigate (1) the rate ratio of severe COVID-19 associated with eligibility for the shielding programme in Scotland across the first and second waves of the epidemic and (2) the relation of severe COVID-19 to transmission-related factors in those in shielding and the general population. Methods: In a matched case-control design, all 178,578 diagnosed cases of COVID-19 in Scotland from 1 March 2020 to 18 February 2021 were matched for age, sex and primary care practice to 1,744,283 controls from the general population. This dataset (REACT-SCOT) was linked to the list of 212,702 individuals identified as eligible for shielding. Severe COVID-19 was defined as cases that entered critical care or were fatal. Rate ratios were estimated by conditional logistic regression. Results: With those without risk conditions as reference category, the univariate rate ratio for severe COVID-19 was 3.21 (95% CI 3.01 to 3.41) in those with moderate risk conditions and 6.3 (95% CI 5.8 to 6.8) in those eligible for shielding. The highest rate was in solid organ transplant recipients: rate ratio 13.4 (95% CI 9.6 to 18.8). Risk of severe COVID-19 increased with the number of adults but decreased with the number of school-age children in the household. Severe COVID-19 was strongly associated with recent exposure to hospital (defined as 5 to 14 days before presentation date): rate ratio 12.3 (95% CI 11.5 to 13.2) overall. The population attributable risk fraction for recent exposure to hospital peaked at 50% in May 2020 and again at 65% in December 2020. Conclusions: The effectiveness of shielding vulnerable individuals was limited by the inability to control transmission in hospital and from other adults in the household. Mitigating the impact of the epidemic requires control of nosocomial transmission.

Item Type:Articles
Keywords:COVID-19/prevention and control, transplant recipient, nosocomial infection, matched case control studies.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McMenamin, Dr James and Goldberg, Prof David and McAllister, Professor David
Authors: McKeigue, P. M., McAllister, D. A., Caldwell, D., Gribben, C., Bishop, J., McGurnaghan, S., Armstrong, M., Delvaux, J., Colville, S., Hutchinson, S., Robertson, C., Lone, N., McMenamin, J., Goldberg, D., and Colhoun, H. M.
College/School:College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Public Health
Journal Name:BMC Medicine
Publisher:BioMed Central
ISSN:1741-7015
ISSN (Online):1741-7015
Copyright Holders:Copyright © 2021 The Authors
First Published:First published in BMC Medicine 19: 149
Publisher Policy:Reproduced under a Creative Commons License

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