Scientists identify the ‘biomarkers’ of long COVID

The pandemic has introduced us to a host of new words and terms – COVID, coronavirus, Delta, Omicron and long COVID.

As the name suggests, long COVID refers to those who continue to experience symptoms long after they contracted COVID. There’s no strict definition of the term ‘long COVID’, but an article published in the online medical journal The Lancet, states, “the general consensus is that long COVID is the failure to return to normal, pre-COVID levels of health”.

This is a very broad definition, and the “failure to return to normal levels of health” covers a wide spectrum of conditions. For some, the ongoing symptoms may be mild, similar to other post-viral ones such as a persistent cough or general aches and pains.

Read: Latest ‘must-have’ device in the fight against COVID

For others, though, the symptoms may be far more debilitating, far worse than those associated with chronic fatigue syndrome. On an ABC Science Friction podcast, three doctors who had contracted COVID a year earlier spoke about the symptoms they were still experiencing and had not foreseen.

One described having a level of “brain fog” so severe that he had given up trying to read as he “couldn’t get past the first sentence”. Another said she was so severely handicapped by long COVID that she needed crutches to walk for any length of time.

Typical symptoms include breathlessness, fatigue and difficulty concentrating and an Australian study undertaken by the Kirby Institute found symptoms could last at least eight months after infection.

Unvaccinated people who contracted the virus were more likely to suffer long COVID.

You’ve had a mild case of COVID. Are you safe from long COVID?

Against the expectations of many, it seems that long COVID can become an issue for anyone who has contracted the virus, even those who experienced the mildest of symptoms, or indeed none at all.

Read: Signs you may have had COVID and not known it

Dr Chansavath Phetsouphanh, a senior research associate at the University of NSW’s Kirby Institute, said: “One of the most surprising aspects of our analysis is that people don’t need to have had severe COVID to experience these ongoing immunological changes; this occurred in people with mild and moderate disease.”

Professor Gail Matthews, Dr Phetsouphanh’s colleague and co-author in a new study published in the journal Nature Immunology, said the study had identified certain biomarkers that were found in long COVID sufferers, indicating a switched-on immune system.

These markers generally do not remain active for long after a viral infection, “The fact we see an abnormal immune signal at this time point really lends validity to the idea of long Covid”, said Prof. Matthews.

Read: I’ve tested positive to COVID. What should I do now?

This has been a relief of sorts to some sufferers who have been met with strong scepticism when discussing the concept of long COVID.

Now that these biomarkers of long COVID, which affects more women than men, have been identified, doctors hope it might be possible to modulate the immune response by targeting interferons – the proteins in cells that fight viral infection – with drugs to treat the debilitating condition.

In the hunt for products to assist long-COVID sufferers, ASX-listed company Bod Australia says it has secured clinical trial authorisation from the Medicines and Healthcare Products Regulatory Agency in the UK, which would be “an important opportunity to build on the growing body of evidence for the use of MediCabilis”.

Have you had ongoing symptoms after contracting COVID? Why not share your experience in the comments section below?

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Written by Andrew Gigacz