Chest CT Scans Reveal Effectiveness of Different COVID Vaccines

Chest CT Scans Reveal Effectiveness of Different COVID Vaccines

Emerging research about the ability of a chest CT scan to differentiate the efficacy of various COVID-19 vaccines could help dispel vaccine hesitancy. A new study, published in the American Journal of Roentgenology, highlights the critical knowledge gained from a retrospective view of chest CT scans of patients who developed COVID pneumonia.

The study was directed by Dr. Simone Vicini of the Sapienza University of Rome. He and his team studied the medical records of 467 patients between December 2021 and February 2022 who received chest CT scans during their hospitalization for COVID-19. The cohorts’ vaccine status included:

  • 251 – Vaccinated

167 had received the BNT162b2 mRNA vaccine (Pfizer)

84 had received the ChAdOx1-S adenovirus vector vaccine (AstraZeneca)

  • 216 – Unvaccinated

NOTE: The ChAdOx1-S vaccine is not currently approved by the United States Food and Drug Administration (FDA) but has received EUA by the World Health Organization (WHO).

Their study yielded some expected results and other unexpected results and data that may help shape future COVID vaccination development and help dispel vaccine hesitancy. Vaccine hesitancy exists not only in the United States but throughout the world. A significant reason for people’s reluctance is the belief that vaccines don’t work because vaccinated individuals may experience breakthrough infections.

Iacopo Carbone, M.D., of the Department of Radiological Sciences at Sapienza University, observed, “Vaccination status was significantly associated with pneumonia severity independent of age and sex.”

Measure Unvaccinated Pfizer Vaccine AstraZeneca Vaccine
Mean CT Severity Score 9.7 5.2 6.2
Crazy Paving on CT 11% 8% 0%
Percent with Pneumonia 85% 49% 51%
Percent with Fever 79% 43% 54%


The findings in this study provide important information in two areas.

  1. Chest CT scan results can help determine vaccine efficacy.
  2. Chest CT scan studies provide radiologists insight into how chest CT scans might vary depending on the patient’s vaccine status and manufacturer.

For example, Italian researchers found that 79% of the COVID patients who developed pneumonia experienced bilateral lung involvement. However, researchers saw statistically significant differences in the three sets of patients.

  • Unvaccinated – 86% had bilateral involvement
  • AstraZeneca ChAdOx1-S vaccine – 90% experienced bilateral involvement
  • Pfizer BNT162b2 vaccine – 57% had bilateral lung involvement

With the results of this study, radiologists can be made aware that COVID patients who received the Pfizer BNT162b2 vaccination may be more likely to have a unilateral presentation of pneumonia.

The study also discovered that patients who received the AstraZeneca vaccine were more likely to experience labored breathing than those who received the Pfizer vaccine.

Although the Italian study is limited in scope, it can be a model for future studies. It used patient data from only one facility and only evaluated the two vaccines available in Italy. However, the evidence is compelling that vaccinated individuals experience less severe disease, decreasing the risk of hospitalization and death.

Based on these facts confirmed by chest CT examinations, a well-planned outreach program may help convince the vaccine-hesitant to get vaccinated.