1928. A Population-Based Propensity Score-Matched Study of COVID-19 Vaccination on Clinical Outcomes in Hospitalized Adult Patients with COVID-19
Authors: Niu Jianli , Sareli Candice , Mayer Daniel , Visbal Alvaro , Sareli Aharon E 
Published: December 2022

Abstract

Background
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause significant morbidity and mortality in hospitalized patients. We aimed to evaluate the impact of 2-dose COVID-19 vaccination on ICU admissions and in-hospital deaths in adult patients with COVID-19.

Methods
Laboratory-confirmed COVID-19 adult patients hospitalized at Memorial Healthcare System, Hollywood, Florida, between June 01, 2021 and September 20, 2021, were retrospectively reviewed. We used 1:1 propensity score matching for demographic characteristics and underlying diseases to construct an unvaccinated cohort similar to the vaccinated cohort. “Fully vaccinated” was defined as a patient who received 2-dose vaccines. Risk of in-hospital mortality or ICU admission was estimated using logistic regression models adjusting for age, gender, race/ethnicity, body mass index, and comorbidities.

Results
3067 unvaccinated and 284 fully vaccinated patients were included. The propensity score–matched cohort included 262 unvaccinated and 262 fully vaccinated patients. The median age was 71.0 (IQR, 60-81) years, 51.3% were men, and 36.2% were white participants. The most common comorbidities were hypertension (452; 86.3%), diabetes (236; 45.0%), and chronic kidney disease (163; 31.1%). At the study closeout of Oct 18, 2021, 70 (13.4%) patients required ICU admission, and 81 (15.5%) patients died. In multivariable-adjusted models, fully vaccinated patients had lower risks of ICU admission and in-hospital mortality compared to unvaccinated patients (Figure 1). Patients who received the Pfizer BioNTech vaccines had comparable risks of ICU admission (adjusted odds ratio [aOR], 0.80; 95% CI, 0.23—2.79; p=0.731) and in-hospital mortality (aOR, 2.99; 95% CI, 0.59—15.3; p=0.187) compared to those received the Moderna vaccines (Figure 2). No difference in hospital length of stay or in ICU length of stay were noted between fully vaccinated and unvaccinated patients. Figure 1.Vaccination reduces the risk of disease severity in propensity score–matched COVID-19 patients admitted to the MHS from June 01 to Sep 20, 2021. Forest plot showing adjusted odds ratio (aOR, diamond) estimates with 95% confidence interval (CI, indicated by the horizontal line) of association between vaccination and risk of disease severity. aORs comparing the vaccinated group with the unvaccinated group were obtained from the multivariable logistic regression models for binary dependent variables. The models were adjusted for age, gender, race/ethnicity, body mass index, and comorbidities (chronic lung disease, chronic kidney disease, chronic heart disease, hypertension, diabetes). ICU, intensive care unit.Figure 2.Comparison of vaccine type on risk of disease severity of COVID-19 among fully vaccinated patients. Forest plot showing adjusted odds ratio (aOR, diamond) estimates with 95% confidence interval (CI, indicated by the horizontal line) of association between vaccine type and risk of disease severity. aORs comparing the Pfizer BioNTech group with the Moderna group were obtained from the multivariable logistic regression models for binary dependent variables. The models were adjusted for age, gender, race/ethnicity, body mass index, and comorbidities (chronic lung disease, chronic kidney disease, chronic heart disease, hypertension, diabetes). ICU, intensive care unit.

Conclusion
Fully vaccinated patients hospitalized with COVID-19 have lower risks of ICU admission and in-hospital mortality than unvaccinated patients. No significant differences were noted in ICU admission and in-hospital mortality between patients who received Moderna vaccines and those received Pfizer BioNTech vaccines.

Disclosures
All Authors: No reported disclosures.