A drug commonly used to treat opioid dependency may also prove life changing for long COVID-19 sufferers.
Queensland scientists have discovered Naltrexone can be used on a low dose to alleviate long COVID's debilitating symptoms, describing it as a "world first finding".
Griffith University researchers say trials to date have been successful using the drug on patients with Chronic Fatigue Syndrome, an illness that has similar symptoms.
They are now confident they can achieve similar results with long COVID sufferers.
"The idea of identifying a drug that is readily on the market with good safety data and repurposing it for another disease is a potential way forward to help people restore their lives and have some normality," Professor Sonya Marshall-Gradisnik told AAP.
Griffith University researchers have identified a way to use the drug to restore a faulty function of immune cells.
When COVID-19 infects the body it can cause a fault in ion channels, which work as a lock and key system for immune cells.
The fault ensures the cells are unable to unlock to receive the appropriate amount of calcium, causing long COVID symptoms like fatigue, brain fog and muscle exhaustion.
"Imagine a fist and a hand covering that fist. The Naltrexone acts on the hand covering the fist and releases it away so it lets the faulty lock and key work properly and restores it," Ms Marshall-Gradisnik said.
Between five to 10 per cent of COVID-19 cases will have lasting symptoms, according to the Australian Institute of Health and Welfare.
Griffith University's National Centre for Neuroimmunology and Emerging Diseases will run a clinical trial in Queensland, NSW, Victoria and Western Australia to test low doses of Naltrexone on long COVID patients aged 18 to 65.
Another will be held for the first time on patients with Chronic Fatigue Syndrome.
Scientists hope to get a better understanding of long COVID and Chronic Fatigue Syndrome, paving the way for potential therapies.
"We have to be very measured in how we progress," Ms Marshall-Gradisnik said.
"The first part is do the clinical trial, look at the data and make an informed decision about where to go from there."
The research has been published in the Frontiers in Immunology.
