Last year, 28-year-old Morgan Cherry worked long hours, went to the gym six days a week and played sports.
But everything was put on hold when he was diagnosed with COVID-19 on Christmas day.
At first Mr Cherry, who is double vaccinated, only had mild symptoms, and it seemed as though the young lawyer wouldn't have much trouble with the virus.
"I felt progressively better as Christmas Day wore on," he said.
"I woke up on Boxing Day feeling better again and then by the following day, I was more or less back to normal."
After three days, the only symptom Mr Cherry felt was fatigue.
But nearly four weeks later, that fatigue has stuck around. And it means he can't yet get his old life back.
"I'm still at a stage where there are more days [where I'm] fatigued than there are days where I feel normal," he said.
He's cancelled his sport commitments, cut down on the gym and is often in bed by 8pm.
"You hear and read all about this long COVID," he said.
"The longer this fatigue and lethargy drags on, the more you start thinking, 'Oh, am I going to be one of the unlucky ones that gets long COVID?'"
With more than a million Australians infected since the Omicron variant wave began, there are a lot of people like Mr Cherry.
Professor Kristine Macartney said people in Morgan's situation shouldn't be too worried.
"Generally speaking, people should be aware that if they've still got symptoms, say two or three weeks after having been infected, the trend is for those symptoms to resolve over time," Professor Macartney said.
But she said anyone with lingering symptoms should take extra care and check in with a healthcare provider.
"Obviously, we've seen a lot of COVID infections in the community right now," she said.
"And most people just need to [ensure] that they're doing all the things that are healthy for them: eating well, sleeping well, getting some gradual return to exercise."
Will Omicron leave a legacy?
Long COVID has been defined by the United States' Centers for Disease Control and Prevention (CDC) as symptoms lasting at least four weeks after being infected with the virus that causes COVID-19.
Estimates vary, but research that has been done on earlier variants — prior to the arrival of Omicron — suggests between 10 and 30 per cent of people who get COVID-19 may have symptoms that persist beyond four weeks.
If that holds true with the Omicron variant, Australia could see hundreds of thousands of people experiencing persistent symptoms and long COVID.
But Professor Macartney said she hoped it wouldn't be that bad.
Vaccinations reduce the severity of COVID-19, meaning Australia's population — which had a double-dose vaccination rate of 78 per cent this week — could be somewhat protected from long COVID, according to Professor Macartney.
And the Omicron variant's tendency to produce less severe disease should also help, she said.
"We hope to see fewer cases of long COVID and particularly the really significant long COVID, where there are substantial symptoms lasting many, many months."
Many infections mean many long COVID cases
David Putrino is an Australian neuroscientist who leads several long COVID rehabilitation clinics at Mount Sinai Health System in New York.
He's a lot less optimistic about what Australia faces as the Omicron wave subsides.
His clinics have treated hundreds of patients with mild COVID-19 who later developed long COVID.
"What we've seen over and over again is that the severity of the disease in the acute phase does not predict who's going to go on to get quite severe long COVID," he said.
And even if vaccination and a less severe variant do reduce the proportion of people who get long COVID, the sheer number of infections Australia is facing now will mean a lot of people will get long COVID, Professor Putrino added.
University of Melbourne public health expert Nancy Baxter agreed.
"Hopefully, with a milder disease, less people will have long COVID," Professor Baxter said.
"But we know with previous variants that even if you had mild disease, there was still some risk of developing it.
"[And] if you're infecting 10 times or 100 times more people, that may mean we see a lot more long COVID than we did with other variants."
'It's been a struggle'
Professor Putrino said people should not try to push through their illness and instead they should rest when they need it.
"There are emerging studies saying that if you get COVID and you don't take adequate rest, you try to push through, that is also predictive of people going on to get long COVID," he said.
He said clinics like his were starting to find ways of helping people with long COVID. The treatments involve retraining brain networks, working on breathing and techniques to deal with extreme fatigue.
Professor Putrino said rehabilitation could be a lot of work.
Morgan Cherry is hopeful he's on the road to recovery, and his fatigue won't become a bad case of long COVID.
"I was probably back to 90 per cent within two or three days of testing positive," he said.
"So it's really been a struggle to get back that lost 10 per cent of normality that I'm still trying to get back."
