The Impact of SARS-CoV-2 Primary Vaccination in a Cohort of Patients Hospitalized for Acute COVID-19 during Delta Variant Predominance.

Daša Stupica,Mirijam Nahtigal Klevišar,Stefan Collinet-Adler,Mario Poljak,Zala Jagodic,Nataša Kejžar

doi:10.3390/jcm11051191

Abstract

Vaccine breakthrough SARS-CoV-2 infections necessitating hospitalization have emerged as a relevant problem with longer time interval since vaccination and the predominance of the Delta variant. The aim of this study was to evaluate the association between primary vaccination with four SARS-CoV-2 vaccines authorized for use in the European Union—BNT162b2, ChAdOx-1S, mRNA-1273 or Ad.26.COV2.S—and progression to critically severe disease (mechanical ventilation or death) and duration of hospitalization among adult patients with PCR-confirmed acute COVID-19 hospitalized during the Delta variant predominance (October–November 2021) in Slovenia. Among the 529 enrolled patients hospitalized with COVID-19 (median age, 65 years; 58.2% men), 175 (33.1%) were fully vaccinated at the time of symptom onset. Compared with 345 unvaccinated patients, fully vaccinated patients with breakthrough infections were older, more often immunocompromised, and had higher Charlson comorbidity index scores. After adjusting for sex, age, and comorbidities, fully vaccinated patients had lower odds for progressing to critically severe disease and were discharged from the hospital earlier than unvaccinated patients. Vaccination against SARS-CoV-2 remains an extremely effective intervention to alleviate morbidity and mortality in COVID-19 patients.

Highlights

Prior infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)generates humoral and cellular correlates of immunity [1–4] and some protection of uncertain duration from re-infection [5–7]
SARS-CoV-2 infections necessitating hospitalization have emerged as a relevant problem with predominance of the Delta variant followed by the Omicron variant and longer time interval since vaccination [13–15]
In this study of adult patients hospitalized due to COVID-19 in a single university medical center in central Europe, fully vaccinated patients with breakthrough SARS-CoV-2 infections progressed less often to critically severe disease and had shorter duration of hospital stay than unvaccinated patients during a period with Delta variant predominance

Summary

Introduction

Prior infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)generates humoral and cellular correlates of immunity [1–4] and some protection of uncertain duration from re-infection [5–7]. Prior infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The permissive accumulation of infections in populations is a poor strategy for controlling the pandemic given the considerable morbidity and mortality of coronavirus disease 2019 (COVID-19). To face this public health challenge, many different types of vaccines against SARS-CoV-2 have been explored using various vaccine platforms, including non-replicating adenoviral vector-based and mRNA strategies [8]. The development, licensing, and distribution of several highly safe and effective vaccines against SARS-CoV-2 have transformed the trajectory of the pandemic by providing significant protection from COVID-19 [9–12]. SARS-CoV-2 infections necessitating hospitalization have emerged as a relevant problem 4.0/).

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