Tulane University scientists used a mouse model to examine tissue after infection had cleared. The work, reported in a scientific journal, compared lungs and brains to separate effects common to severe respiratory infections from those unique to SARS-CoV-2 (the virus that causes COVID-19).
In the lungs, both viruses produced similar signs of lasting injury. Researchers found immune cells that failed to fully stand down and an increased buildup of collagen, a protein linked to scarring. Those changes can stiffen lung tissue and help explain continued shortness of breath. After influenza, the lungs showed a repair response: specialized cells appeared in damaged areas and began rebuilding the airway lining. That repair response was largely missing after COVID-19.
The largest differences were in the brain. Although neither virus was detected in brain tissue, mice that had COVID-19 showed persistent brain inflammation weeks later and tiny areas of bleeding. Gene analysis showed ongoing inflammatory signaling and disruption of pathways for serotonin and dopamine, systems linked to mood, thinking and energy. These persistent brain changes were largely absent after influenza.
The findings point to vascular and immune changes that may contribute to neurological symptoms such as brain fog, fatigue and mood changes. The research aims to provide a clearer basis for monitoring patients and developing treatments to prevent lasting damage.
Difficult words
- tissue — part of the body with similar cells
- collagen — protein linked to scarring in tissues
- scarring — formation of fibrous tissue after injury
- inflammation — body's immune response causing redness or swelling
- persistent — continuing for a long time without stopping
- pathway — series of steps or signals in the bodypathways
- serotonin — chemical in brain that affects mood
- dopamine — brain chemical important for movement and reward
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How might missing the lung repair response after COVID-19 affect a person’s daily life?
- Which of the brain symptoms mentioned (brain fog, fatigue, mood changes) would worry you most, and why?
- What kinds of monitoring or treatments would you expect doctors to consider to prevent lasting damage after a serious respiratory infection?
Related articles
Africa uses AI to strengthen health systems and self-reliance
At the CPHIA conference in Durban, Africa CDC said AI and digital tools can help protect 1.4 billion people, improve surveillance and support primary health care. Data governance, infrastructure and domestic financing are key concerns.
Engineered antibodies could block cytomegalovirus
A research team created changed antibodies that stop human cytomegalovirus from disabling immune responses. Lab tests show the antibodies reduce virus spread, but researchers say more testing is needed before they can be used in people.
Emory study: 2023–24 COVID vaccine gives lasting antibodies
Emory University measured antibody responses in 24 people after the 2023–24 monovalent vaccine targeting Omicron XBB.1.5. The study found long-lasting antibodies, cross-reactive protection with the ancestral WA1 strain, and a 2.8-fold boost from immune imprinting.
