Severe COVID-19 and influenza infections may leave lasting damage in the lungs that increases the risk of lung cancer months or even years later. New research from the University of Virginia (UVA) Health suggests that these serious infections can create conditions in the lungs that allow cancer to grow more easily. The study also brings encouraging news: vaccination appears to prevent many of these harmful changes and may reduce the long-term risk.
Researchers led by Jie Sun found that severe viral infections can “reprogramme” immune cells in the lungs. Instead of protecting the body, these altered cells may create an environment that supports tumour growth over time. Because of this, the research team recommends that doctors carefully monitor patients who have recovered from severe COVID-19, influenza, or pneumonia so that lung cancer can be detected early, when treatment is more effective.
Respiratory infections such as COVID-19 and the flu are common causes of lung injury, but their long-term effects have not been fully understood. To explore this, the researchers studied both laboratory mice and human patient data. They found that mice with severe lung infections were more likely to develop lung cancer and had higher death rates from the disease. Similar patterns were observed in people, where those who had been hospitalised for COVID-19 showed a higher incidence of lung cancer.
The study identified a 1.24-fold increase in lung cancer risk among patients who had experienced severe COVID-19. Importantly, this increased risk was seen regardless of smoking status or other health conditions. According to Jeffrey Sturek, these findings suggest that severe respiratory infections may need to be considered alongside traditional risk factors such as smoking. In the future, doctors may recommend regular lung screening for certain high-risk patients who have recovered from serious infections.
The researchers also uncovered possible biological explanations for this increased risk. Severe infections were found to alter key immune cells, including neutrophils and macrophages, which normally help defend the lungs. After infection, some of these cells appeared to promote inflammation and create a “pro-tumour” environment. Changes were also observed in the epithelial cells lining the lungs, which could further contribute to cancer development.
Reassuringly, vaccination seemed to prevent many of these harmful effects by reducing the severity of infection. The increased cancer risk was mainly seen in patients with severe illness, while those with mild COVID-19 did not show the same pattern. In fact, they showed a slight decrease in risk. The researchers emphasise that preventing severe infection through vaccination may also help reduce long-term complications, including those linked to cancer.
Given the large number of people worldwide who have experienced severe respiratory infections, the findings have important implications for healthcare. The researchers suggest that individuals recovering from serious lung infections—especially those with a history of smoking—may benefit from closer monitoring for lung cancer. They hope this work will help doctors identify high-risk patients earlier and lead to better strategies for prevention and treatment in the future.
More information: Wei Qian et al, Respiratory viral infections prime accelerated lung cancer growth, Cell. DOI: 10.1016/j.cell.2026.02.013
Journal information: Cell Provided by University of Virginia Health System
