ArticleInfluenza and other respiratory viruses2023
Comparative hospitalization risk for SARS-CoV-2 Omicron and Delta variant infections, by variant predominance periods and patient-level sequencing results, New York City, August 2021-January 2022.
Article in Influenza and other respiratory viruses, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers, 2 of them syntheses that pooled it.
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Who cites it
17 citing papers in PubMed, 2 syntheses or guidelines pooled it, 27 citations in OpenAlex.
- Neutralising antibodies and protection from progression to severe COVID-19: A meta-analysis.PLoS medicine · 2026Pooled it
- Clinical outcomes of the severe acute respiratory syndrome coronavirus 2 Omicron and Delta variant: systematic review and meta-analysis of 33 studies covering 6 037 144 coronavirus disease 2019-positive patients.Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases · 2023Pooled it
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- Longitudinal analysis of Covid-19 infection trends and in-hospital mortality across six pandemic waves in Tunisia.Archives of public health = Archives belges de sante publique · 2025Article
- From Entry to Outbreak in a High School Setting: Clinical and Wastewater Surveillance of a Rare SARS-CoV-2 Variant.Viruses · 2025Article
- Applying prospective tree-temporal scan statistics to genomic surveillance data to detect emerging SARS-CoV-2 variants and salmonellosis clusters in New York City.International journal of epidemiology · 2025Article
- The Clinical Anatomy of SARS-CoV-2 Variants of Concern in Central Greece During October 2020-July 2022.Microorganisms · 2024Article
- Bacterial and Viral Co-Infections in COVID-19 Patients: Etiology and Clinical Impact.Biomedicines · 2024Article
- Evaluation of the New York City COVID-19 case investigation and contact tracing program: a cascade of care analysis.BMC public health · 2024Article
- What Is the Economic Benefit of Annual COVID-19 Vaccination From the Adult Individual Perspective?The Journal of infectious diseases · 2024Article
- Development and characterization of monoclonal antibodies recognizing nucleocapsid protein of multiple SARS-CoV-2 variants.Heliyon · 2024Article
- Clinical characteristics and risk factors associated with diverse manifestations of COVID-19 in patients aged 85 years and older.Frontiers in public health · 2024Article
- Assessment of clinical characteristics and viral load in individuals infected by Delta and Omicron variants of SARS-CoV-2.Heliyon · 2023Article
- Comparative hospitalization risk for SARS-CoV-2 Omicron and Delta variant infections, by variant predominance periods and patient-level sequencing results, New York City, August 2021-January 2022.Influenza and other respiratory viruses · 2023Article
- A chronological review of COVID-19 case fatality rate and its secular trend and investigation of all-cause mortality and hospitalization during the Delta and Omicron waves in the United States: a retrospective cohort study.Frontiers in public health · 2023Article
- Elder and booster vaccination associates with decreased risk of serious clinical outcomes in comparison of Omicron and Delta variant: A meta-analysis of SARS-CoV-2 infection.Frontiers in microbiology · 2023Article
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Authors and funding
8 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundComparing disease severity between SARS-CoV-2 variants among populations with varied vaccination and infection histories can help characterize emerging variants and support healthcare system preparedness.
methodsWe compared COVID-19 hospitalization risk among New York City residents with positive laboratory-based SARS-CoV-2 tests when ≥98% of sequencing results were Delta (August-November 2021) or Omicron (BA.1 and sublineages, January 2022). A secondary analysis defined variant exposure using patient-level sequencing results during July 2021-January 2022, comprising 1-18% of weekly confirmed cases.
resultsHospitalization risk was lower among patients testing positive when Omicron (16,025/488,053, 3.3%) than when Delta predominated (8268/158,799, 5.2%). In multivariable analysis adjusting for demographic characteristics and prior diagnosis and vaccination status, patients testing positive when Omicron predominated, compared with Delta, had 0.72 (95% CI: 0.63, 0.82) times the hospitalization risk. In a secondary analysis of patients with sequencing results, hospitalization risk was similar among patients infected with Omicron (2042/29,866, 6.8%), compared with Delta (1780/25,272, 7.0%), and higher among the subset who received two mRNA vaccine doses (adjusted relative risk 1.64; 95% CI: 1.44, 1.87).
conclusionsHospitalization risk was lower among patients testing positive when Omicron predominated, compared with Delta. This finding persisted after adjusting for prior diagnosis and vaccination status, suggesting intrinsic virologic properties, not population-based immunity, explained the lower severity. Secondary analyses demonstrated collider bias from the sequencing sampling frame changing over time in ways associated with disease severity. Representative data collection is necessary to avoid bias when comparing disease severity between previously dominant and newly emerging variants.
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