Impact of prior vaccination on clinical outcomes of patients with COVID-19

Abstract

Fully vaccinated people remain at risk of Coronavirus Disease 2019 (COVID-19). We examined association between prior vaccination and clinical outcomes in patients with COVID-19. Overall, 387 patients with mild-to-severe COVID-19 were enrolled. Patients were considered fully vaccinated at least 14, 7, and 14 days after receiving the second dose of ChAdOx1 nCoV-19 or mRNA-1273, second dose of BNT162b2, or single dose of Ad26.COV2.S, respectively. The primary outcomes (risk of pneumonia, requirement of supplemental oxygen, and progression to respiratory failure) were compared between vaccinated and unvaccinated patients. Logistic regression analysis was performed to identify factors associated with the outcomes. There were 204 and 183 patients in the vaccinated and unvaccinated groups, respectively. The vaccinated group was significantly older and had more comorbidities than the unvaccinated group. Patients in the unvaccinated group were significantly more likely to develop pneumonia (65.6% vs. 36.8%) or require supplemental oxygen (29.0 vs. 15.7%) than the vaccinated group. The vaccinated group had a significantly shorter time from symptom onset to hospital discharge than the unvaccinated group (10 vs. 11 days; p <0.001). The proportion of patients who progressed to respiratory failure did not differ significantly between groups. In multivariable analyses, vaccination was associated with an approximately 70% and 82% lower likelihood of pneumonia and supplemental oxygen requirement, respectively. Being vaccinated was associated with a significantly lower risk of pneumonia and severe disease when breakthrough infection developed. Our findings support continuous efforts to increase vaccine coverage in populations.

The COVID-19 Vaccination Coverage in ICU Patients with Severe COVID-19 Infection in a Country with Low Vaccination Coverage—A National Retrospective Analysis

“…The vaccinated patients with severe COVID-19 infection admitted to ICU presented a higher rate of ischemic heart disease, chronic kidney disease, chronic dialysis, and a higher cumulated number of associated medical conditions. These results are similar to other studies that report a notably higher incidence of comorbidities in vaccinated patients requiring ICU admission [22,[30][31][32][33][34][35] and a weaker association between vaccination and reduced risk of hospitalization for patients with impaired immune status [22]. The high rate of comorbidities might be explained by the exacerbation of coexisting diseases requiring ICU hospitalization or by lower vaccine effectiveness in this population [32,33].…”

The surveillance of patients hospitalised with COVID-19 in Norway: a comparison of two register-based systems

“…At the same time, the proportion of patients 0 -17 years admitted due to COVID-19 who were registered with a URI code increased. This is in line with findings among paediatric patients from elsewhere during a period of increasing Omicron dominance [32]. Our results highlight the challenge of using ICD-10 codes for the surveillance of patients hospitalised due to COVID-19, not least the importance of age-and timespecific definitions, and ongoing validation of these to consider temporal changes in patient cohorts and virus characteristics.…”

“…Based on their respective definitions, both Norway and Denmark have previously reported differences in the proportion of patients admitted due to COVID-19 over time and by patient characteristics, such as age and vaccination status [10,28]. This is in line with studies reporting temporal changes in patient cohorts and the clinical presentation of hospitalised patients over time [31][32][33][34]. While certain ICD-10 code combinations closely followed the overall trend in new patients admitted with COVID-19 as main cause, the distribution of ICD-10 codes by main cause and sensitivity and specificity of selected code combinations for representing COVID-19 as main cause varied by age and time.…”

Clinical and Epidemiological Risk Factors Associated with Hospitalization and Mortality Rate of COVID-19 Patients in Banja Luka County: Retrospective Observational Cohort Study on 40,000 patients

“…A systematic review of 41 worldwide studies showed that most vaccines prevented people from getting infected, as well as reduced the number of people with severe disease [42]. Results from the study in Korea showed better outcomes of vaccinated patients with mild to severe clinical course [43].…”