icon-    folder.gif   Conference Reports for NATAP  
  Conference on Retroviruses
and Opportunistic Infections
Seattle, Washington
Feb 19-22 2023
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Paxlovid Reduced by 98% Hospitalization:
  CROI 2023 Feb 20-23
Heather Henderson
David A. Wohl, William Fischer, Luther Bartelt, David van Duin, Joseph J. Eron, Sonia Napravnik
University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
webcast: https://www.croiwebcasts.org/console/player/51741?mediaType=slideVideo&
program abstract
Given effectiveness of SARS-CoV-2 vaccines and outpatient antiviral and monoclonal antibody therapy for reducing progression to severe COVID-19, we sought to estimate the impact of these interventions on risk of hospitalization following SARS-CoV-2 infection in a large US healthcare system.
Methods: All patients ≥18 of age in the UNC Health system, with first positive SARS-CoV-2 RT-PCR test or U07.1 ICD-10-CM (diagnosis date) during 07/01/2021-05/31/2022, were included. The outcome was first hospitalization with U07.1 ICD-10-CM primary diagnosis ≤14 days after SARS-CoV-2 diagnosis date. SARS-CoV-2 vaccinations were included if received ≥14 days prior to diagnosis. Outpatient therapies were included if administered after diagnosis date and before hospital admission. Age, gender, race, ethnicity, and comorbidities associated with COVID-19 (using ICD-10-CM, if documented ≥14 days prior to diagnosis date) were also evaluated. Risk ratios for hospitalization were estimated using generalized linear models, and predictors identified using extreme gradient boosting using feature influence with Shapley additive explanations algorithm.
Results: The study population included 54,886 patients, 41% men and 27% ≥60 years of age. One-third of SARS-CoV-2 diagnoses occurred July-December 2021 and 67% December-May 2022 (predominantly Delta and Omicron variants, respectively). Overall 7.0% of patients were hospitalized for COVID-19, with median hospitalization stay of 5 days (IQR: 3-9). 32% and 12% of patients received ≥1 SARS-CoV-2 vaccine dose and outpatient therapy, respectively.
Unadjusted and age-adjusted hospitalization risk decreased with vaccination and outpatient therapy (TABLE). Comparing patients who received 3 vaccine doses versus none we observed a 66% relative reduction in risk, with stronger association for more recent vaccination.
For patients who received nirmatrelvir/ritonavir versus no therapy we observed a 99% relative reduction in risk.
In predictive models, older age was the most influential predictor of being hospitalized with COVID-19, while vaccination and outpatient therapy were the most influential factors predicting non-hospitalization.
[heart conditions, chronic kidney disease, Hispanic ethnicity, Delta variant all are associated with greater hospitalization risk.]
Conclusion: The impact of recent SARS-CoV-2 vaccination and outpatient antiviral and monoclonal antibody therapy on reducing COVID-19 hospitalization risk was striking in this large healthcare system covering Delta and Omicron variant timeframes. SARS-CoV-2 vaccinations and outpatient therapeutics are critical for preventing severe COVID-19.