Research has shown that people who have suffered from a serious respiratory viral infection such as COVID-19 or severe influenza may have an increased risk of developing lung cancer later in life. Viral infection can change the lung tissue and immune environment, creating a condition in which cancer is likely to grow months to years later.
Researchers at the University of Virginia School of Medicine recently published the results of an analysis of whether serious respiratory viral infections such as COVID-19 and the flu can have long-term effects on lung tissue (Respiratory viral infections prime accelerated lung cancer growth) in the international journal Cell.
Dr. Jie Sun, who led the study, explained, “Severe COVID-19 or flu can leave the lungs in a long-term inflammatory state, and these changes can create an environment in which cancer can grow easily over time.”
The researchers explained in the background of the study that respiratory viral infections, such as the flu or coronavirus, are common causes of lung damage, but how this damage affects long-term cancer risk is not fully known.
Increasing trends in lung cancer in both mouse and human data
The researchers analyzed data from patients who had been hospitalized due to coronavirus infection and laboratory mice.
First, in mouse experiments, individuals who suffered serious lung infections were more likely to develop lung cancer than those who did not, and the risk of dying from lung cancer also tended to increase.
Similar results were observed in human data. People who had been hospitalized for COVID-19 had a 24% higher risk of developing lung cancer. This association was maintained even after adjusting for smoking history and comorbidities.
Researchers confirmed that viral infection affects immune cells in the lungs. In particular, it was analyzed that problems occur as the functions of neutrophils and macrophages, which play a role in protecting the lungs, change. Inflammation continues as some neutrophils do not function normally, which can create an environment in which cancer can easily grow.
Structural changes were also observed in the epithelial cells surrounding the lungs and air sacs.
Vaccine, potential preventive effect
There were some positive aspects to the research results. Studies have shown that prior vaccination tends to suppress many of the changes in the lungs that can promote cancer growth. Additionally, a slightly lower risk of lung cancer was observed in people with mild COVID-19 symptoms.
Dr. Sun explained, “The vaccine not only prevents hospitalization due to infection, but also has the potential to help reduce long-term aftereffects, such as immune damage that can increase the risk of cancer.”
People experiencing severe respiratory infections raise the need for long-term follow-up
The researchers said that the results of this study provide new implications for patient management after severe respiratory viral infections.
“Until now, the best-known risk factor for lung cancer is smoking, but in the future, serious respiratory viral infections may also need to be considered as potential risk factors,” said co-researcher Dr. Jeffrey Steurek.
He added, “Just as regular lung CT scans are recommended for high-risk patients with a smoking history, future studies also need to examine follow-up strategies for patients who have experienced severe viral infections.”
Lung cancer is a major cancer in Korea as well.
Meanwhile, according to data from the Central Cancer Registry Headquarters released in 2026, lung cancer ranked second with 11% of all cancer occurrences as of 2023. It ranked 2nd among male cancers and 4th among female cancers. By age group, those in their 70s accounted for the largest portion at 33%, followed by those in their 60s (31%) and those in their 80s or older (22%).
Experts consider quitting smoking to be the most important way to prevent lung cancer. The risk increases as the amount of smoking and the duration of smoking increases, and it is known that it takes a considerable period of time for the risk of lung cancer to decrease to the level of a non-smoker even after quitting smoking.
In addition, reducing exposure to occupational and environmental hazardous substances, maintaining a balanced diet and healthy lifestyle habits are important to maintain lung health.
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Q1. Does getting COVID-19 or the flu increase the risk of lung cancer?
A. This study observed an association with an increased risk of lung cancer, especially in severe respiratory viral infections that require hospitalization. This trend was not evident in mild infections, and in some cases a trend toward reduced risk was observed.
Q2. Does this study mean that COVID-19 directly causes lung cancer?
A. Not really. The study showed a correlation with the increased incidence of lung cancer and did not confirm a direct causal relationship. Additional research is needed.
Q3. What is the most important way to prevent lung cancer?
A. Experts consider quitting smoking to be the most important way to prevent lung cancer. It is also helpful to reduce occupational exposure to hazardous substances and maintain a healthy lifestyle.
