COVID & Flu: How Viral Infections May Raise Lung Cancer Risk – & Why Vaccination Helps

Severe respiratory viral infections, like COVID-19 and influenza, can leave a lasting mark on the lungs, potentially increasing the risk of lung cancer years later, according to fresh research from UVA Health. While vaccination appears to offer significant protection against these harmful long-term effects, the findings underscore the importance of monitoring individuals who have recovered from severe cases of these illnesses.

The Link Between Viral Infection and Lung Cancer Risk

Researchers at the University of Virginia School of Medicine, led by Jie Sun, PhD, discovered that serious viral infections can “reprogram” immune cells within the lungs, creating an environment conducive to tumor growth. This reprogramming can occur months or even years after the initial infection. The study, published in the journal Cell, examined both laboratory mice and human patients, revealing a consistent association between severe viral infections and an increased risk of lung cancer.

Specifically, the research team found a 1.24-fold increase in lung cancer incidence among patients who had been hospitalized with COVID-19. This increased risk persisted even after accounting for factors like smoking history and other underlying health conditions, known as comorbidities. UVA Health Newsroom details the findings.

How Infections Alter the Lung Environment

The study pinpointed key changes within the lungs following severe viral infections. Immune cells called neutrophils and macrophages, normally responsible for protecting the lungs, were significantly altered. These changes led to the creation of an inflamed, “pro-tumor” environment, essentially paving the way for cancer cells to thrive. The researchers observed alterations in the epithelial cells lining the lungs and the air sacs crucial for breathing.

Jeffrey Sturek, MD, PhD, a UVA physician-scientist involved in the project, explained that these findings suggest a need to consider severe respiratory viral infections similarly to established risk factors like smoking. “We’ve known for a long time that things like smoking increase the risk for lung cancer,” Sturek said. “The results from this study suggest that we may need to think about severe respiratory viral infection similarly.” This could mean recommending closer monitoring, including routine CT scans, for high-risk patients after a severe respiratory illness.

Vaccination as a Protective Measure

The research offered a reassuring note: prior vaccination appeared to prevent the cancer-promoting changes observed in the lungs. Vaccines work by training the immune system to effectively combat infections, reducing the severity of illness. The UVA team found that the increased cancer risk was primarily observed in patients who experienced severe COVID-19 infections, while those with mild cases actually showed a slight decrease in risk.

This highlights the importance of vaccination not only in preventing acute illness but also in potentially mitigating long-term health consequences, including cancer risk. The UVA Health Newsroom emphasizes this preventative aspect.

Beyond COVID-19: Implications for Influenza and Other Respiratory Viruses

While the study focused on COVID-19, the findings have broader implications for other severe respiratory infections, such as influenza. The underlying mechanisms identified – the reprogramming of immune cells and the creation of a pro-tumor environment – are likely relevant to a range of viral pneumonias. This suggests that individuals recovering from severe cases of influenza or other serious respiratory illnesses may also benefit from enhanced lung cancer surveillance.

The researchers acknowledge that countless survivors of severe COVID-19 and other respiratory illnesses may face an increased chance of developing lung cancer in the years ahead. This underscores the need for continued research and proactive monitoring strategies.

Understanding the Biological Mechanisms

The UVA team believes they’ve identified the specific mechanisms driving this increased risk. Severe viral lung infections dramatically affect the function of neutrophils and macrophages, altering their ability to protect the lungs. These changes contribute to the inflamed environment where cancer can take hold. The study also revealed significant changes to the epithelial cells that line the lungs and air sacs.

This deeper understanding of the biological changes wrought by severe lung infections could pave the way for the development of targeted treatments to improve patient outcomes and potentially prevent cancer development. SciTechDaily provides further context on the study’s findings.

What’s Next: Enhanced Surveillance and Targeted Therapies

Sun and his colleagues are advocating for enhanced lung cancer surveillance for individuals recovering from severe respiratory viral infections, particularly those with a history of smoking. This could involve more frequent screenings, such as low-dose CT scans, to detect cancer at its earliest, most treatable stages.

the researchers are hopeful that their findings will stimulate the development of new therapies aimed at reversing the immune cell reprogramming and mitigating the pro-tumor environment created by severe viral infections. The ultimate goal is to identify patients at higher risk and develop targeted interventions to prevent and treat lung cancer following pneumonia.

The research was supported by multiple grants from the National Institutes of Health and other organizations, highlighting the collaborative effort driving this important work. UVA’s Beirne B. Carter Center for Immunology Research and UVA Comprehensive Cancer Center played key roles in the study, leveraging their expertise in infection, cancer, and immunology.