In a new study from Pusan National University Hospital, researchers found COVID-19 breakthrough infections in fully vaccinated patients tend to be milder than those of partially vaccinated or unvaccinated patients.
COVID-19 vaccines are effective and critical tools for bringing the pandemic under control. However, vaccines are not 100% effective at preventing illness.
Breakthrough infections are defined as the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA) or antigen in a respiratory specimen collected from a person 14 days or more after receiving all recommended doses of COVID-19 vaccines.
Breakthrough cases are on the rise with the highly transmissible Omicron variant.
Therefore, it is important to know how vaccination impacts not only COVID-19 disease severity but also clinical data and medical imaging results.
In the study, the team analyzed data from adult patients registered in an open data repository for COVID-19 between June and August 2021.
Hospitalized patients with baseline chest X-rays were divided into three groups, according to their vaccination status.
Of the 761 hospitalized patients with COVID-19, the mean age was 47 years, and 385 (51%) were women. Forty-seven patients (6.2%) were fully vaccinated (breakthrough infection), 127 were partially vaccinated (17%), and 587 (77%) were unvaccinated.
The team found fully vaccinated status was linked to a lower risk of requiring supplemental oxygen than unvaccinated status, as well as lower risk of intensive care unit (ICU) admission.
The results also showed associations between the risk of severe disease and clinical characteristics such as higher age, history of diabetes, lymphocytopenia, thrombocytopenia, elevated LDH (lactate dehydrogenase), and elevated CRP (C-reactive protein).
Notably, age was also found to be an important predictor of more severe disease in COVID-19 patients, even in those with a breakthrough infection.
The researchers noted that observed differences in clinical characteristics may reflect differences in vaccination priorities based on underlying comorbidities.
Despite these differences, mechanical ventilation and in-hospital death occurred only in the unvaccinated group.
Further analysis showed that fully vaccinated patients were at much lower risk of requiring supplemental oxygen and of ICU admission than unvaccinated patients.
Although additional research will be needed as different variants emerge, this study sheds light on the clinical effectiveness of COVID-19 vaccination in the context of breakthrough infections.
If you care about COVID, please read studies about new drug that could prevent COVID-19, and people with COVID-19 infections may age much faster.
For more information about health, please see recent studies about antibodies that can neutralize Omicron, and results showing this drug treatment may prevent COVID death and lung damage.
The study is published in the journal Radiology and was conducted by Yeon Joo Jeong et al.
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