One in three people who catch coronavirus will suffer at least one symptom of long COVID, a new study has found, which means as many as 33,000 Australians may have struggled with the mysterious, lingering effects of the virus.

The just-released study into long COVID, a phenomenon where people who have recovered from the virus remain hit with debilitating symptoms for months afterwards, is one of the most in-depth to have been conducted, involving 270,000 people in the US.

Researchers found 37 per cent of patients suffered at least one long COVID symptom three to six months after infection.

READ MORE: How 'long COVID' leaves survivors facing strange and frightening futures

The most common symptoms were breathing problems, abdominal symptoms, fatigue, pain and anxiety or depression.

People hospitalised with coronavirus were more likely to suffer long COVID, the study found, particularly symptoms of ongoing and crushing fatigue and a condition called brain fog.

"The best way that I can describe the brain fog is just like I'm sleepwalking 24/7," Maddy Bourke told 9News earlier this month.

"It feels like I'm constantly in that dreamlike state."

The 24-year-old teaching student from Melbourne is one of many Australians, young and old, battling long COVID and the mental and emotional toll that fight can bring.

Eight months after catching COVID-19, Ms Bourke still suffers weakness, fatigue and shortness of breath.

"It's very, very draining (and) very tiring to struggle through the days."

More than 101,000 Australians have tested positive for coronavirus since the start of the pandemic, with possibly one-third experiencing long COVID according to the study's estimations.

Do you suffer from long COVID? Email follow the group on Twitter here.