Pneumonia Frequency and Severity in Patients With Symptomatic COVID-19: Impact of mRNA and Adenovirus Vector Vaccines.

Background: Additional evidence of the role of COVID-19 vaccination in reducing pneumonia frequency and severity in the setting of breakthrough infection could help combat ongoing vaccine hesitancy. Objective: To compare the frequency and severity of pneumonia on chest CT in patients with confirmed COVID-19 between unvaccinated patients and patients fully vaccinated by mRNA or adenovirus vector vaccines. Methods: This retrospective single-center study included 467 patients (250 men, 217 women; mean age, 65±17 years) who underwent chest CT between December 15, 2021, and February 18, 2022 during hospitalization for symptomatic COVID-19, confirmed by reverse transcriptase-polymerase chain reaction assay. A total of 216 patients were unvaccinated, and 167 and 84 patients were fully vaccinated (defined as receipt of the second dose at least 14 days before COVID-19 diagnosis) by the BNT162b2 mRNA vaccine or the ChAdOx1-S adenovirus vector vaccine, respectively. Semi-quantitative CT severity scores (CT-SS; 0-25 scale) were determined; CT-SS of 0 indicated absence of pneumonia. Presence of bilateral involvement was assessed in patients with pneumonia. Associations were explored between vaccination status and CT findings. Results: The frequency of an absence of pneumonia was 15% (32/216) in unvaccinated patients, 29% (24/84) in patients fully vaccinated with ChAdOx1-S vaccine, and 51% (85/167) in patients fully vaccinated with BNT162b2 vaccine (unvaccinated and ChAdOx1-S vs BNT162b2: p<.001; unvaccinated vs ChAdOx1: p=.08). Mean CT-SS was significantly higher in unvaccinated patients (9.7±6.1) than in patients fully vaccinated with BNT162b2 (5.2±6.1) or ChAdOx1-S (6.2±5.9) vaccines (both p<.001). Full vaccination was significantly associated with CT-SS independent of patient age and sex (estimate = -4.46; p<.001). Frequency of bilateral lung involvement was significantly higher in unvaccinated patients (158/184, 86%) and in patients fully vaccinated with ChAdOx1-S vaccine (54/60, 90%) than in patients fully vaccinated with BNT162b2 vaccine (47/82, 57%) (both p<.001). Conclusion: Pneumonia frequency and severity were lower in patients with full vaccination by mRNA and adenovirus vector vaccines experiencing breakthrough infections in comparison with unvaccinated patients. Clinical Impact: The visual observation by radiologic imaging of the protective effect of vaccination on lung injury in patients with breakthrough infections provides additional evidence supporting the clinical benefit of vaccination.

[1]  Clinical findings, viral load, and outcomes of COVID-19: Comparison of patients with negative and positive initial chest computed tomography , 2022, PloS one.

[2]  A. Elmokadem,et al.  Comparison of chest CT severity scoring systems for COVID-19 , 2022, European Radiology.

[3]  M. Lipsitch,et al.  SARS-CoV-2 breakthrough infections in vaccinated individuals: measurement, causes and impact , 2021, Nature Reviews Immunology.

[4]  M. Muszkat,et al.  Comparing the clinical efficacy of COVID-19 vaccines: a systematic review and network meta-analysis , 2021, Scientific Reports.

[5]  The Crazy-Paving Pattern in Chest CT Imaging of COVID-19 Patients: An Alarming Sign for Hospitalization , 2021, Iranian Journal of Radiology.

[6]  R. Kishony,et al.  Initial report of decreased SARS-CoV-2 viral load after inoculation with the BNT162b2 vaccine , 2021, Nature Medicine.

[7]  I. Bellos,et al.  Chest CT severity score and radiological patterns as predictors of disease severity, ICU admission, and viral positivity in COVID-19 patients , 2021, Respiratory Investigation.

[8]  M. Zeegers,et al.  Demographic risk factors for COVID-19 infection, severity, ICU admission and death: a meta-analysis of 59 studies , 2021, BMJ Open.

[9]  M. Hefeda.  CT chest findings in patients infected with COVID-19: review of literature , 2020, Egyptian Journal of Radiology and Nuclear Medicine.

[10]  T. Kwee,et al.  Chest CT in COVID-19: What the Radiologist Needs to Know , 2020, Radiographics : a review publication of the Radiological Society of North America, Inc.

[11]  Wei Wang,et al.  Early prediction of disease progression in COVID-19 pneumonia patients with chest CT and clinical characteristics , 2020, Nature Communications.

[12]  K. Sklinda,et al.  COVID-19 severity scoring systems in radiological imaging – a review , 2020, Polish journal of radiology.

[13]  C. Catalano,et al.  Chest CT score in COVID-19 patients: correlation with disease severity and short-term prognosis , 2020, European Radiology.

[14]  Association of “initial CT” findings with mortality in older patients with coronavirus disease 2019 (COVID-19) , 2020, European Radiology.

[15]  Derya Yakar,et al.  Chest CT Imaging Signature of Coronavirus Disease 2019 Infection , 2020, Chest.

[16]  Ran Yang,et al.  Chest CT Severity Score: An Imaging Tool for Assessing Severe COVID-19 , 2020, Radiology. Cardiothoracic imaging.

[17]  Kunwei Li,et al.  CT image visual quantitative evaluation and clinical classification of coronavirus disease (COVID-19) , 2020, European Radiology.

[18]  C. Zheng,et al.  Time Course of Lung Changes On Chest CT During Recovery From 2019 Novel Coronavirus (COVID-19) Pneumonia , 2020, Radiology.

[19]  Kevin A Hallgren,et al.  Computing Inter-Rater Reliability for Observational Data: An Overview and Tutorial. , 2012, Tutorials in quantitative methods for psychology.

[20]  J. R. Landis,et al.  A one-way components of variance model for categorical data , 1977 .