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A study at the University of Virginia has suggested that severe cases of Covid-19 or flu may create conditions in the lungs that could increase the likelihood of tumour development
Researchers found that when patients experience serious cases of Covid-19 or influenza, the infection can leave the lungs in a prolonged state of inflammation, which can make it easier for cancer cells to grow.
Six years after the Covid-19 pandemic began, many who were infected during the Delta and Omicron waves still remember how the virus left some with long-haul symptoms, hospitalisations, and serious breathing problems. But could these infections also raise the risk of lung cancer years later?
A recent study by researchers at the University of Virginia has drawn global attention after suggesting that severe cases of Covid-19 or flu may create conditions in the lungs that could increase the likelihood of tumour development in the future. The research points to the possibility that the long-term effects of viral infections may extend beyond short-term lung damage.
While the findings do not prove that infections directly cause cancer, they highlight how major illnesses may leave lasting changes in the body that could influence disease risk later in life.
What The New Study Actually Found
The study examined how severe respiratory infections affect the lungs at a cellular level. Researchers found that when patients experience serious cases of COVID-19 or influenza, the infection can leave the lungs in a prolonged state of inflammation.
This inflammation can alter the lung’s biological environment in ways that may make it easier for cancer cells to grow. In laboratory models, scientists observed that severe infections could “prime” lung tissue for tumour development by changing immune responses and tissue repair processes.
Another notable finding was related to vaccination. The researchers observed that vaccinated subjects were less likely to develop the harmful inflammatory changes that appeared to trigger tumour growth in the lungs. This suggests that vaccines against Covid and influenza may play a protective role beyond simply preventing infection.
However, experts stress that the research is still in early stages and further human studies are needed before drawing firm conclusions.
How Respiratory Infections Could Trigger Cancer
The link between infections and cancer is not entirely new. Certain viruses are already known to increase cancer risk. For example, the human papillomavirus (HPV) is associated with cervical cancer, while hepatitis viruses are linked to liver cancer.
In the case of respiratory infections, scientists believe the mechanism may involve chronic inflammation and immune system changes.
“Severe infections like Influenza or Covid-19 have triggered strong immune responses in the lungs. During infection, immune cells release inflammatory chemicals to fight viruses. If inflammation has persisted for a long period, the lung tissue undergoes repeated cycles of damage and repair. During this repair process, cells divide rapidly to replace injured cells. Every time cells divide, small DNA errors have the potential to occur. In rare situations, these errors accumulate, and abnormal cells are allowed to grow, which is one pathway through which cancer could develop,” said Dr Nidhi Patni, Director, Radiation Oncology, Narayana Hospital, Jaipur.
So, can frequent cold cause lung cancer? Dr Patni said It has not been proven directly yet. Though the symptoms of a long-lasting cough from infection may resemble lung cancer symptoms, the underlying causes are usually different, she added.
Researchers also believe that infections could activate dormant cancer cells that already exist in the body but remain inactive. Some studies suggest that inflammatory responses caused by infections may “wake up” these dormant cells, allowing them to multiply and form tumours.
Another possible factor is the way the body repairs damaged lung tissue after infection. During healing, cells divide rapidly to replace damaged areas. In rare cases, errors in this repair process may lead to abnormal cell growth.
For How Long Can Covid Symptoms Impact The Lungs?
One of the key findings of the research is that the potential cancer risk appears to be associated mainly with severe infections rather than mild cases.
Patients who require hospitalisation for Covid-19 or influenza often experience significant lung inflammation and tissue damage. In contrast, people with mild infections usually recover without lasting changes in lung structure.
“Covid-19 can affect the lungs even after the infection has resolved. While most people recover within a few weeks, some patients, especially those who had moderate or severe illness, may experience breathlessness, fatigue, or a persistent cough for several months. This happens due to inflammation in lung tissues, which may temporarily reduce lung capacity. With time, medications, breathing exercises, and pulmonary rehabilitation, lung function usually improves,” said Dr Rakesh Godara, Additional Director, Pulmonology, CK Birla Hospitals, Jaipur.
Doctors, therefore, stress that the results should not alarm people who have experienced mild infections. The study specifically highlights severe respiratory disease as the primary area of concern.
Can Covid-19 Vaccines Prevent Lung Damage?
If severe respiratory infections do increase the likelihood of lung cancer in some cases, preventing these infections becomes even more critical. Vaccination campaigns against influenza and Covid-19 could potentially reduce long-term complications beyond immediate illness.
The research may also influence how doctors monitor patients who have recovered from severe respiratory disease. In the future, people who experience serious lung infections may require closer follow-up to detect possible long-term complications.
“Vaccination against Covid-19 has been one of the most effective tools to reduce severe lung disease. When vaccines have been administered, the immune system has already been trained to recognize the virus. This preparation has helped the body respond quickly when exposure has occurred. As a result, the chances of severe pneumonia, hospitalization, and extensive lung inflammation have been significantly reduced… Vaccines may not eliminate infection, but the severity of illness has been markedly lowered,” said Dr Shubham Sharma, Senior Consultant, Pulmonology, Narayana Hospital, Jaipur.
Health experts say the study also reinforces the importance of early treatment for respiratory infections. Timely medical care can reduce inflammation and prevent complications that might otherwise lead to lasting lung damage.
Why The Findings Should Be Interpreted Cautiously?
Despite the attention the study has received, scientists caution that the findings should be interpreted carefully.
The research does not prove that COVID-19 or influenza directly causes lung cancer. Instead, it suggests a possible biological pathway through which severe infections could increase susceptibility.
“Many studies show associations rather than direct cause-and-effect relationships. Factors like smoking, pollution exposure, and underlying lung disease can influence results. Therefore, findings from early studies need larger and long-term research before drawing strong conclusions,” stressed Dr Godara.
Another limitation is that much of the research was conducted using laboratory models. Long-term studies involving human populations will be necessary to determine whether the same effect occurs in real-world settings.
“Cancer development has taken many years. A recent infection may have revealed or accelerated a pre-existing abnormality rather than creating a completely new cancer. More long-term human studies are still required,” Dr Patni added.
Researchers therefore stress that infections are likely only one piece of a much larger puzzle when it comes to cancer risk.
Can Age Help Prevent Lung Cancer Risk? What Precautions To Take
“Age alone has not prevented lung cancer. In fact, cancer risk has generally increased as people grow older because genetic mutations have accumulated over time. However, lifestyle choices across all ages have strongly influenced lung health. The most powerful preventive step has been avoiding tobacco exposure. Cigarette smoke has introduced thousands of carcinogenic chemicals into the lungs. Reducing air pollution exposure, using protective equipment in hazardous workplaces, and maintaining regular health check-ups have also helped reduce risk,” said Dr Sharma.
Vaccination against respiratory infections, regular exercise, and maintaining good lung hygiene have supported stronger respiratory immunity. Early screening for high-risk individuals, especially long-term smokers, has allowed suspicious lung nodules to be detected and treated earlier, he added.
Public health experts say the findings underline the need for stronger vaccination coverage, better air quality control and improved healthcare access to reduce the burden of respiratory disease.
The possibility that viral infections may contribute to cancer risk illustrates how interconnected different aspects of health can be.
While more research is needed to confirm the findings, the study serves as a reminder that preventing severe illness remains one of the most effective ways to protect long-term health.
March 13, 2026, 08:35 IST
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