New research has shown long COVID-19 is causing brain fog and memory loss in patients for more than a year.
The study found about 20 per cent of those suffering from long COVID-19 can experience brain impairment for at least 12 months without improvement.
Long COVID-19 is categorised as people suffering from symptoms like brain fog, fatigue, and shortness of breath a month after contracting the virus.
Professor Bruce Brew from Sydney's St Vincent's Hospital said researchers have analysed 128 patients over 12 months and found the impacts of long COVID-19 on the brain don't go away after a year.
"We're hopeful it will take another year or less to see some improvement in their condition but we just don't know," he said.
"The study has also identified a marker of cognitive impairment – a nerve toxin in a particular pathway in the brain, which opens up the possibility of repurposing existing drugs to modulate this toxin, which could potentially give us a treatment."
Brew added those suffering from long COVID-19 didn't necessarily become really sick with the virus when they had it.
"There's a common misconception that if you're not severely ill with COVID then you won't experience brain fog, but in our study nine out of ten of those suffering long COVID were not hospitalised," he said.
Professor Steven Faux helps run the long COVID clinic at St Vincent's Hospital and said he is seeing eight to 10 new patients a week with the disease, primarily young people.
"What we're finding is it's actually affecting younger people, and they're finding it really difficult to be able to continue working," he said.
Researchers added long COVID-19 has debilitating effects on sufferers and the symptoms have been likened to a traumatic brain injury.
"The impact of long COVID on some is significant. I had one patient, a businessman who had to sell his business because he could no longer focus on contracts and negotiations during meetings," Brew said.
"We're seeing people with slow thought processes and confusion which is very similar to a Traumatic Brain Injury," Faux added.