Impact of Severe Acute Respiratory Syndrome Coronavirus 2 Variants on Inpatient Clinical Outcome.

Background: Prior observation has shown differences in COVID-19 hospitalization risk between SARS-CoV-2 variants, but limited information describes hospitalization outcomes.
Methods: Inpatients with COVID-19 at 5 hospitals in the eastern United States were included if they had hypoxia, tachypnea, tachycardia, or fever, and SARS-CoV-2 variant data, determined from whole-genome sequencing or local surveillance inference. Analyses were stratified by history of SARS-CoV-2 vaccination or infection. The average effect of SARS-CoV-2 variant on 28-day risk of severe disease, defined by advanced respiratory support needs, or death was evaluated using models weighted on propensity scores derived from baseline clinical features.
Results: Severe disease or death within 28 days occurred for 977 (29%) of 3369 unvaccinated patients and 269 (22%) of 1230 patients with history of vaccination or prior SARS-CoV-2 infection. Among unvaccinated patients, the relative risk of severe disease or death for Delta variant compared with ancestral lineages was 1.30 (95% confidence interval [CI]: 1.11-1.49). Compared with Delta, the risk for Omicron patients was .72 (95% CI: .59-.88) and compared with ancestral lineages was .94 (.78-1.1). Among Omicron and Delta infections, patients with history of vaccination or prior SARS-CoV-2 infection had half the risk of severe disease or death (adjusted hazard ratio: .40; 95% CI: .30-.54), but no significant outcome difference by variant.
Conclusions: Although risk of severe disease or death for unvaccinated inpatients with Omicron was lower than with Delta, it was similar to ancestral lineages. Severe outcomes were less common in vaccinated inpatients, with no difference between Delta and Omicron infections.
Competing Interests: Potential conflicts of interest. The Maryland Department of Health collaborates for research with BioRad, Hologic, and DiaSorin. J. B. has equity/entitlement to future royalties in miDiagnostics. B. T. G. is a member of the Food and Drug Administration (FDA) Pulmonary-Asthma Drug Advisory Committee and a board member of the Society of Bedside Medicine and has received consulting fees from Janssen Research and Development, LLC (related to vaccine trial case adjudication); Gilead Sciences, Inc (related to COVID therapeutics); and Atea Pharmaceuticals, Inc (related to COVID therapeutics). R. B. is a consultant for Merck & Co and Hologic. R. B. also reports royalties or licenses from emocha Health, support for attending meetings and/or travel from Hologic, and participation on a Data Safety Monitoring Board or Advisory Board for Merck. H. H. M. reports the following grants or contracts unrelated to this work: National Institutes of Health (NIH) UM1AI0686, NIH UM1 AI068613-14, NIH R01 DA045556-04S1, NIH 3U54HL143541-02S2, NIH 4UH3CA211396-03, and NIH R01 CA243393 and receipt of equipment, materials, drugs, medical writing, gifts, or other services related to research contract from BioRad, DiaSorin, and Hologic. D. C. G. reports grants or contracts unrelated to this work from Illumina, Inc; IDbyNDA, Inc; and Fisher Center Discovery Program, Johns Hopkins; consulting fees from bioMerieux, Inc; and payment or honoraria for lectures, presentations, speaker’s bureaus, manuscript writing, or educational events from the American Association of Clinical Chemistry and Pan American Society of Clinical Virology. A. G. reports unrelated grants or contracts from NIH and Unitaid and the Centers for Disease Control and Prevention (CDC); participation on an NIH/NIAID Advisory Council and Indo US Science Technology Governing Board; and roles on the IMPAACT Network TB Scientific Committee and World Health Organization (WHO) MDR TB Guidelines Committee. M. L. R. reports grants or contracts unrelated to this work from Critical Path Institute/FDA, paid to their institution. S. L. Z. reports the following grants or contracts unrelated to this work: 1R01AR073208-01 (Shah) (1 April 2018–31 March 2023), NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), Autoantibodies Define Scleroderma Subgroups with Distinct Relationships to Cancer; UL1TR003098 (Ford) (1 June 2019–30 April 2024), NIH/National Center for Advancing Translational Sciences (NCATS), Johns Hopkins Institutional Clinical and Translational Science Award. S. L. Z. also reports a role as Co-Director for Data Science, JHM inHealth Precision Medicine (paid to their institution). These conflicts of interest are being managed by the Johns Hopkins University in accordance with its conflict-of-interest policies. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.
(© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)