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. 2022 Aug 25;9(9):ofac438.
doi: 10.1093/ofid/ofac438. eCollection 2022 Sep.

Description of Hospitalizations due to the Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Based on Vaccination Status

Matthew A Moffa  1 , Nathan R Shively  1 , Dustin R Carr  2 , Derek N Bremmer  2 , Carley Buchanan  2 , Tamara L Trienski  2 , Max W Jacobs  3 , Vikram Saini  1 , Thomas L Walsh  1
Affiliations

Description of Hospitalizations due to the Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Based on Vaccination Status

Matthew A Moffa et al. Open Forum Infect Dis. .

Abstract

Background: Limited descriptive data exist regarding the clinical characteristics of hospitalizations due to the severe acute respiratory syndrome coronavirus 2 Omicron variant based on vaccination status.

Methods: This was a retrospective cohort study of all patients hospitalized with a diagnosis of coronavirus disease 2019 (COVID-19) between 15 January 2022 and 15 February 2022 across 9 hospitals in a large health network. Data were extracted by manual records review.

Results: A total of 351 of 452 (77.7%) unvaccinated, 209 of 331 (63.1%) fully vaccinated, and 107 of 163 (65.6%) boosted patients hospitalized with a COVID-19 diagnosis were determined to be admitted specifically due to COVID-19 (P < .001). Most (85%) boosted patients admitted due to COVID-19 were at least 65 years old and/or had severe immunosuppression, compared to 72.2% of fully vaccinated and 60.7% of unvaccinated patients (P < .001). Significantly more unvaccinated patients (34.2%) required >6 L/minute of supplemental oxygen compared to fully vaccinated (24.4%) and boosted (25.2%) patients (P = .027). The age-adjusted vaccine effectiveness (VE) against hospitalization due to COVID-19 was estimated to be 81.1% and 94.1% for full vaccination and boosted status, respectively, whereas VE against mortality related to COVID-19 was estimated to be 84.7% and 94.8%, respectively.

Conclusions: During the Omicron BA.1 sublineage wave, unvaccinated patients hospitalized with a COVID-19 diagnosis were more likely than vaccinated patients to be admitted specifically due to COVID-19. Despite being younger with fewer comorbidities, unvaccinated patients required higher levels of care. Vaccination with a booster provides the greatest protection against hospitalization and death from COVID-19.

Keywords: COVID-19; Omicron; SARS-CoV-2; hospitalization; vaccination.

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Figures

Figure 1.
Figure 1.
Patient screening. Abbreviations: COVID-19, coronavirus disease 2019; OSH, outside hospital; US, United States.
See this image and copyright information in PMC

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