American Study Finds That Airway and Vascular Structural Abnormalities Persist in Individuals 3-4 Years After COVID-19 Infection
Nikhil Prasad Fact checked by:Thailand Medical News Team Jul 03, 2026 1 hour, 15 minutes ago
Medical News: For many people, recovering from COVID-19 does not necessarily mean their lungs have completely healed. A new American study has found that structural changes affecting the airways and blood vessels of the lungs can still be detected three to four years after the initial infection. Even more concerning, these lingering abnormalities were linked to persistent symptoms such as fatigue, brain fog, cough, shortness of breath, and a poorer quality of life despite many patients having nearly normal results on standard breathing tests.
Advanced CT scans reveal that hidden airway and blood vessel abnormalities can remain for up to four years
after COVID-19 infection, even when routine lung tests appear normal
American researchers from the University of Iowa, including experts from IIHR-Hydroscience & Engineering, the Department of Mechanical Engineering, the Department of Internal Medicine, the Department of Radiology, and the Roy J. Carver Department of Biomedical Engineering, collaborated with scientists from the Department of Computer Science and Engineering at Texas A&M University to investigate the long-term impact of COVID-19 on the lungs.
Advanced CT Imaging Reveals Hidden Lung Damage
The study followed 80 individuals who had recovered from COVID-19, with approximately 81 percent having been infected with the original pre-Alpha strain. Participants underwent detailed quantitative CT scans and pulmonary function tests approximately five months after infection and again about 39 months later. Their results were compared with those of 78 healthy volunteers who had never been infected.
Although conventional lung function tests showed that most participants had lung capacity within the normal range, researchers consistently found reduced gas exchange capacity, indicating that oxygen was not moving from the lungs into the bloodstream as efficiently as in healthy individuals. This finding suggests that routine breathing tests alone may fail to detect ongoing lung damage.
Airway and Blood Vessel Remodeling Continues Years Later
One of the study's most striking discoveries was that while early inflammatory changes seen shortly after infection had largely resolved, important structural abnormalities remained years later.
The researchers found persistent narrowing of the airways together with thickening of the airway walls. At the same time, the lung's blood vessels underwent significant remodeling, with a reduction in smaller blood vessels and enlargement of larger vessels. Quantitative CT imaging also showed that bronchovascular tissue patterns remained elevated long after infection, indicating ongoing remodeling involving both the airways and surrounding blood vessels.
The investigators also observed increased ventilation heterogeneity, meaning that air was no longer being distributed evenly throughout the lungs. This uneven airflow may help explain why many patients continue experiencing symptoms despite appearing normal during standard lung function testing.
Persistent Symptoms Closely Match the Structural Change
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Medical News report highlights one of the most important aspects of the study: the abnormalities detected on advanced CT scans closely corresponded with the symptoms patients continued to experience years after recovering from COVID-19.
More than half of the participants reported ongoing fatigue, brain fog or gastrointestinal problems. Over 30 percent continued experiencing cough, heart palpitations and high blood pressure. Around 80 percent reported at least some degree of breathlessness.
Detailed analysis showed that airway remodeling was strongly associated with persistent cough and loss of taste or smell. Vascular remodeling was linked to fatigue, shortness of breath, blood clots, heart palpitations, high blood pressure and pulmonary embolism. Symptoms including brain fog, headaches and chest pain were associated with abnormalities affecting both the airways and blood vessels simultaneously. The researchers also found that individuals who required hospitalization during their original COVID-19 illness generally showed more pronounced structural remodeling years later.
Quality of Life Remains Significantly Affected
Participants also completed several validated health questionnaires evaluating respiratory symptoms, fatigue, cough and daily functioning. Despite mostly normal spirometry results, they consistently reported poorer respiratory health and reduced quality of life compared to healthy individuals.
The researchers found that patients with the highest levels of airway and vascular remodeling also tended to report the greatest limitations in everyday physical activity. Importantly, these persistent structural abnormalities were not significantly influenced by asthma, chronic obstructive pulmonary disease (COPD), vaccination status or repeat COVID-19 infections, suggesting that the long-term lung changes were primarily driven by long COVID itself.
Conclusion
The study provides compelling evidence that COVID-19 can leave behind long-lasting structural damage that remains hidden from conventional lung function testing. Even after three to four years, many survivors continue to experience airway narrowing, blood vessel remodeling and impaired oxygen transfer that contribute to persistent fatigue, brain fog, breathing difficulties and reduced quality of life. These findings suggest that advanced quantitative CT imaging could become an important tool for identifying long COVID patients who continue to suffer from hidden lung abnormalities, allowing physicians to better monitor recovery, assess future health risks and develop targeted therapies aimed at preventing permanent cardiopulmonary damage.
The study findings were published in the peer reviewed journal: Respiratory Research.
https://link.springer.com/article/10.1186/s12931-026-03784-2
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Read Also:
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/articles/long-covid
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