Scientists find what causes long COVID symptoms

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In a new study from UNSW, researchers found unvaccinated people with long COVID – even those whose initial infection was mild or moderate – have a sustained inflammatory response for at least eight months following their infection.

They found that there is a strong and sustained inflammation that indicates prolonged activation of the immune system response detectable for at least eight months following initial infection.

This suggests that long COVID is very different from other infections.

In the study, the team examined blood samples from 62 people with and without long COVID for a variety of ‘immune biomarkers’.

They compared these to people who had not had COVID-19 and they found persistently elevated levels of Type I and Type III interferons – types of protein cells make in response to the presence of a virus.

These interferons generally disappear after the infection clears, but in patients with long COVID they found they were present for an extended period.

Approximately 30% of unvaccinated people who contracted COVID and were followed in the study experienced some long COVID symptoms.

The researchers say that understanding the immune profile for long COVID will help the development of treatment and management of long COVID.

This study provides the strongest evidence to date for a clear biological basis for the clinically apparent syndrome of long COVID.

The team says the next steps are to apply this new understanding to other COVID-19 variants, and to further research to inform the treatment and management of long COVID.

If you care about COVID, please read studies about why some people get ‘long COVID’ while others don’t, and how Long COVID could harm your immune system.

For more information about health, please see recent studies about supplement that could keep dementia at bay, and results showing this drug combo can cut risk of stroke and heart attack by half.

The study is published in Nature Immunology. One author of the study is Dr. Chansavath Phetsouphanh.

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