Long COVID may cause lasting lung and brain damage, study shows

Long COVID is a condition where symptoms of COVID-19 persist for weeks or months after the initial infection has cleared.

People with Long COVID often experience fatigue, shortness of breath, and “brain fog,” even if their initial illness was mild.

New research in mice sheds light on why coronavirus infections can have longer-lasting effects than influenza.

In the study published by European Medical Journala, researchers compared the long-term impact of coronavirus with influenza A on the lungs and brain.

Both viruses caused lung inflammation, but coronavirus led to ongoing tissue damage, including scarring, abnormal repair, and persistent activation of inflammatory and clotting pathways.

Influenza, by contrast, triggered a strong early immune response followed by effective lung repair, helping explain why breathing difficulties are more common after coronavirus infection.

The study also found that coronavirus affected the brain, even though the virus itself was not present there. Mice infected with coronavirus showed early microbleeds and sustained brain inflammation.

Changes in gene activity suggested blood vessel problems, immune system overactivity, and disrupted signaling in areas controlling hormones and sensory processing.

These changes mirror neurological symptoms reported by people with long COVID, such as fatigue and cognitive difficulties. Influenza did not produce these brain effects.

The findings suggest that long COVID is not just about lingering virus, but rather ongoing immune activation, blood vessel damage, and impaired tissue repair.

The research also points to lasting effects on how organs communicate, including the lung-brain connection.

While mouse studies cannot fully replicate human disease, these insights could help scientists develop targeted treatments to reduce inflammation, prevent lung scarring, and protect the brain.

Further clinical studies are needed to confirm these mechanisms in people, but this work helps explain why coronavirus can leave a longer-lasting mark on the body than influenza.