Can the Flu Cause Long-Term Lung Damage? Here’s What Science Says

When most people think of the flu, they picture a high fever, body aches, and a week spent in bed. But beneath those familiar symptoms, influenza can cause far more serious problems — especially in the lungs. Far from being “just a bad cold,” the flu directly attacks the respiratory system, triggering inflammation that can damage delicate lung tissue.

New research is uncovering why this damage happens and why it can be so dangerous. Scientists at the Hudson Institute of Medical Research recently identified a protein called Gasdermin D, which fuels runaway inflammation and cell death in the lungs, leading to severe complications. At the same time, researchers from the University of Nottingham found that another protein, Apolipoprotein D (ApoD), may explain why older adults are particularly vulnerable to deadly flu infections.

Together, these discoveries reveal that the flu’s hidden impact goes well beyond fever and fatigue. It can inflame, scar, and weaken the lungs — sometimes with long-lasting consequences. In this article, we’ll explore how the flu damages your lungs, why certain groups are at greater risk, and what new research could mean for future treatments.

How the flu affects your lungs

Unlike common cold viruses that mainly irritate the nose and throat, the flu virus has a unique ability to penetrate into the lower respiratory tract, directly infecting the delicate epithelial cells that line the lungs. This is where the real damage begins.

When the flu virus enters the lungs, it doesn’t just trigger a cough or congestion. It sets off an immune response designed to fight infection. In mild cases, the body clears the virus with minimal damage. But in more severe infections, the immune system can become overactive, flooding the lungs with inflammatory cells and chemicals. This creates swelling, tissue damage, and fluid buildup that make it harder to breathe.

For some, this damage leads to secondary complications such as pneumonia — either from the virus itself or from bacteria taking advantage of weakened lung defenses. In high-risk individuals, including older adults and those with chronic health conditions, the combination of viral attack and immune overreaction can turn a typical flu case into a life-threatening illness.

Read related article: Influenza A vs. Influenza B: What are the Differences

What new research reveals about lung damage

For years, doctors have known that severe influenza can leave patients with damaged lungs, but exactly why this happens has been less clear. Recent discoveries are now shedding light on the molecular mechanisms that drive this damage — and why some groups are hit harder than others.

Gasdermin D

Researchers at the Hudson Institute of Medical Research uncovered the role of a protein called Gasdermin D (GSDMD) in severe flu infections. Normally, the immune system’s inflammatory response is meant to protect the body, but when over-activated, it becomes harmful. GSDMD acts like a trigger for a type of cell death called pyroptosis — an explosive, inflammatory process that bursts lung cells open.

This not only kills infected cells but also releases chemical signals that summon large numbers of immune cells like neutrophils. This results in a “cytokine storm” and runaway inflammation that destroys delicate lung tissue. In animal models, blocking or removing GSDMD dramatically reduced lung injury, viral burden, and death rates, pointing to it as a promising future therapeutic target.

Apolipoprotein D

At the same time, a study from the University of Nottingham identified a different culprit that may explain why influenza is especially deadly for older adults. They focused on Apolipoprotein D (ApoD), a protein that increases in the body with age. ApoD interferes with the immune system’s ability to control inflammation effectively.

In older patients, higher ApoD levels appear to weaken the lungs’ defenses, allowing the flu to cause more severe infections and greater tissue damage. This breakthrough suggests that targeting ApoD could help develop treatments to protect elderly populations, who make up a large share of annual flu deaths.

Key takeaways from the studies

Together, these findings show that flu-related lung damage is not just about the virus itself, but about how the body reacts. Too much inflammation (via GSDMD) and poor immune regulation (via ApoD) both contribute to the severe, sometimes fatal outcomes of influenza. Understanding these mechanisms could pave the way for new therapies that go beyond antiviral drugs, focusing instead on calming damaging immune responses while still allowing the body to fight the infection.

Why lung damage from flu is dangerous

The fever and fatigue that come with influenza usually fade in a week or so — but the damage left behind in the lungs can be far more serious and, in some cases, long-lasting. When the flu inflames and injures lung tissue, it creates vulnerabilities that increase the risk of dangerous complications.

Higher risk of pneumonia

Damaged lung tissue provides the perfect environment for secondary infections, especially bacterial pneumonia. After the flu weakens the lungs, bacteria like Streptococcus pneumoniae can take hold, leading to severe illness that often requires hospitalisation.

Respiratory failure

In severe cases, the combination of swelling, fluid buildup, and cell death in the lungs can impair oxygen exchange. This can lead to acute respiratory distress syndrome (ARDS), a life-threatening condition where the lungs can no longer supply the body with enough oxygen.

Worsening of chronic illnesses

People living with asthma, COPD, or heart disease are especially vulnerable. Influenza-induced inflammation can worsen their conditions, triggering flare-ups or serious complications that extend well beyond the infection itself.

Long-term impacts

Even after recovery, some people may experience lasting damage. Scarring of the lung tissue can reduce lung capacity, making breathing more difficult and increasing susceptibility to future respiratory infections. For older adults, this loss of lung function can significantly impact independence and quality of life.

Who is at most risk?

Not everyone who catches the flu will experience severe lung damage. For many, it’s a miserable but temporary illness. But certain groups face a much higher risk of complications, partly because of how their immune systems respond to infection.

Older adults

The elderly are among the most vulnerable. Research shows that age-related changes, such as higher levels of Apolipoprotein D (ApoD), impair the immune system’s ability to control inflammation. This makes older adults more likely to suffer excessive lung damage and life-threatening complications from the flu.

Young children

Children under five, especially infants, have developing immune systems and smaller airways. This makes them more prone to severe respiratory infections and hospitalisation.

People with chronic health conditions

Those living with asthma, COPD, heart disease, or diabetes are at greater risk because the flu can worsen their underlying condition, creating a dangerous cycle of inflammation and respiratory stress.

Immunocompromised individuals

People with weakened immune systems — whether due to cancer treatments, organ transplants, or autoimmune conditions — often cannot mount an effective defense against the flu. This allows the virus to spread more aggressively in the lungs.

Pregnant women

Pregnancy alters the immune system and puts extra strain on the lungs and heart, increasing the likelihood of flu-related complications.

Can the lungs recover from flu damage?

The good news is that for most healthy people, the lungs have a remarkable ability to repair themselves after a bout of influenza. Once the virus is cleared and inflammation subsides, lung tissue gradually heals, and breathing returns to normal within weeks.

But recovery isn’t always straightforward. The extent of healing depends on how severe the infection was, as well as the person’s age and overall health.

Mild to moderate cases

• Infections limited to the upper airways or mild inflammation in the lungs usually resolve without lasting effects.
  

• Symptoms such as cough and fatigue may linger for a few weeks, but lung function typically returns to normal.

Read related article: RSV vs. COVID-19 vs. Influenza: All You Need to Know

Severe infections

• In cases where the flu triggers pneumonia, ARDS, or cytokine-driven lung injury, recovery is longer and more complicated.
  

• Tissue damage may leave behind scarring (fibrosis), which reduces lung elasticity and capacity.
  

• People who survive severe flu may continue to experience breathlessness, fatigue, or reduced exercise tolerance for months.

Long-term consequences

• Repeated or severe flu infections can gradually weaken lung health over time.
  

• This is particularly concerning for older adults or people with existing respiratory diseases like asthma or COPD.
  

• Some studies suggest that severe influenza may even increase the risk of chronic lung conditions later in life.

How to protect your lungs from flu complications

While you can’t completely avoid the flu, there are steps you can take to reduce the risk of serious lung damage and support faster recovery if you do get sick. Prevention and proactive lung care are the best defences.

1. Get vaccinated

The annual flu vaccine remains the most effective way to protect against severe influenza. Even if you catch the flu, vaccination can reduce the severity of symptoms and lower the risk of complications like pneumonia or hospitalisation. To stay up to date, check current recommendations and eligibility for free vaccines through the Australian Government Department of Health.

2. Support your immune system

A balanced diet, good sleep, hydration, and regular physical activity all help your immune system fight infections more effectively. Managing stress also plays a role, as chronic stress can weaken immunity.

If your diet needs an extra boost, supplements such as vitamin C, vitamin D, or zinc may provide added support during flu season — particularly for people who are deficient.

3. Avoid smoking and pollutants

Cigarette smoke and environmental pollutants damage the lungs and make them more vulnerable to infections. Avoiding these irritants gives your lungs the best chance to recover after illness.

Read related article: Tips and Techniques to Strengthen Your Lungs After Smoking

4. Manage underlying conditions

If you have asthma, COPD, diabetes, or heart disease, following your treatment plan and staying in close contact with your healthcare provider is essential. The flu can easily worsen these conditions if they aren’t well managed.

5. Strengthen and maintain lung health

Improving your baseline lung function makes it easier to cope with respiratory infections:

• Breathing exercises can expand lung capacity and improve oxygen exchange.
  

• Devices like AirPhysio, an oscillating positive expiratory pressure (OPEP) device, help keep the airways clear by loosening and mobilising mucus. This not only supports lung hygiene during flu recovery but also improves overall lung capacity when used regularly.
  

• Such tools are especially valuable for people with asthma, COPD, or anyone who wants to strengthen their lungs against future infections.

Shop AirPhysio devices at Aussie Pharma Direct.

6. Prevention is better than cure

Avoiding exposure to the flu virus in the first place is one of the most effective ways to protect your lungs. Along with good hand hygiene and avoiding close contact with people who are unwell, wearing a high-quality mask in crowded or high-risk settings adds another layer of protection. Options like P2 or N95 respirators are designed to filter out fine airborne particles while still being breathable, making them especially useful during flu season or in healthcare environments. By reducing your chances of catching the flu in the first place, you also reduce the risk of developing lung complications.

7. Seek medical care early

Don’t ignore warning signs like shortness of breath, chest pain, high fever, or fatigue that worsens instead of improving. Early treatment — including antiviral medications where appropriate — can make a critical difference in preventing lung complications.

Conclusion: The future of flu research

For decades, flu treatment has focused mainly on antivirals and supportive care. But new discoveries are shifting attention toward how the body reacts to infection, rather than the virus alone.

The breakthroughs by researches done by the Hudson Institute of Medical Research and the University of Nottingham point toward a future where host-directed therapies work alongside vaccines and antivirals to not only fight the virus but also prevent the lung damage caused by runaway inflammation.

Until then, the best protection remains prevention and proactive lung care: staying up to date with vaccinations, supporting your immune system, managing existing conditions, and strengthening lung health with tools like breathing exercises and airway-clearance devices.

By combining what we know now with the promise of future therapies, we can move closer to a time when the flu is no longer a hidden threat to our lungs — but a challenge we can meet with knowledge, prevention, and resilience.