Vaccination and Reduced Severity of COVID-19 Pneumonia Viewed at Chest Radiography.

Editor:

We read with great interest the article by Dr. Lee and colleagues published online in Radiology on February 1, 2022 (1). In their large cohort of 716 hospitalized patients with coronavirus disease (COVID-19), vaccinated patients exhibited fewer chest computed tomography findings of COVID- 19 pneumonia than unvaccinated patients. Additionally, the need for ventilatory support and the frequency of intensive care unit admission were significantly lower in the vaccinated group than in the unvaccinated group (1).

In a similar vein, we reviewed our own data on the impact of vaccination on COVID-19 pneumonia severity in our hospital, which is in the eastern part of Lombardy, Italy. Our hospital was one of the hot spots of the COVID-19 pandemic in Italy. We selected chest X-rays (CXRs) performed in our emergency room between November 2021 and February 2022 only on COVID-19 patients with respiratory symptoms for whom information on COVID-19 vaccination status was available. We considered both hospitalized and discharged patients. Patients who had not completed their vaccination course or previously had COVID-19 were excluded. We ranked the disease severity using a dedicated CXR scoring system (Brixia score) for patients with COVID-19 (2-5). To analyze differences between the vaccinated and unvaccinated groups, baseline characteristics (patients’ age and gender) and Brixia scores were compared using Mann-Whitney U test and chi-square test.

Notification of this retrospective analysis was presented to our local ethics committee.

Of 205 patients who had CXR performed in our emergency room, there were 109 who were vaccinated, 96 who were unvaccinated. Age and gender were similar in the two groups (p=.50). The Brixia score was higher in the unvaccinated group (median, 5; interquartile range, 3-7) than in the vaccinated group (median, 1; interquartile range, 0-6) (p<0.001). The percentage of CXRs without lung abnormalities was higher in the vaccinated group (36%) than in the unvaccinated group (13%) (p<0.001).

The data presented by Lee et al. and our own preliminary data are concurrent: both highlight the crucial role of COVID-19 vaccination to overcome this new disease – providing imaging evidence of vaccine efficacy and providing hope for a gradual return to normalcy.