Severe respiratory infections, caused by COVID-19 or even certain flu strains, could leave lasting damage in the lungs, increasing the long-term risk of cancer. This observation comes from research conducted by scientists at the University of Virginia.
The research team, led by Jie Sun, analyzed the effects of severe respiratory viral infections on mice and human patients. They found that people hospitalized for COVID-19 had an increased risk of being diagnosed with lung cancer, independent of factors such as smoking. Similarly, mice that had suffered severe lung infections were more likely to develop cancer and die from it.
These findings indicate that prolonged inflammation after infection creates a favorable environment for tumor formation.
Illustrative image from Pixabay
Experiments on mice helped understand why this risk increases. Severe infections cause significant changes in immune cells, including neutrophils and macrophages, which normally protect lung tissue.
After infection, some neutrophils adopt abnormal behavior, contributing to a persistent inflammatory environment that promotes tumor growth. Furthermore, significant alterations were observed in epithelial cells, which line the lungs and respiratory alveoli, reinforcing this trend.
Vaccination appears to offer protection against these harmful effects. By reducing the severity of infections, vaccines prevent the biological alterations that could lead to cancer. People who had mild cases of COVID-19 show a decreased risk, unlike those who experienced severe forms.
This shows that preventing severe infections through vaccination can indirectly help reduce the risk of lung cancer.
Based on these discoveries, the researchers recommend increased medical monitoring for patients who have survived severe respiratory infections, such as pneumonia. Early detection of lung cancer could improve the chances of effective treatment, similar to approaches used for high-risk smokers.
This study, published in the journal
Cell, paves the way for a better understanding of the links between infectious diseases and cancer.