A study has found a link between severe respiratory infections and a higher long-term risk of lung cancer. Researchers discovered that serious infections such as COVID-19, influenza, or pneumonia can leave the lungs in a long-lasting inflammatory state that may encourage tumor development.
The research showed that patients who were hospitalized for COVID-19 had about a 1.24-times higher risk of developing lung cancer later, even when smoking history and other health conditions were taken into account. Scientists believe the reason may be changes in the immune system. After severe infection, immune cells such as neutrophils and macrophages can behave abnormally and create an environment that supports tumor growth months or even years after recovery.
The study also found that vaccination may reduce this risk by preventing the severe illness that causes these long-term immune changes. Because of this, researchers suggest that people who survive serious respiratory infections—especially smokers—may benefit from closer monitoring, including routine CT scans to detect possible lung cancer early.
The findings, published in the journal Cell, suggest that severe viral pneumonia could become recognized as an additional risk factor for lung cancer, similar to smoking. Researchers say identifying patients with lasting immune changes could help doctors decide who needs more careful cancer screening.