Post-viral brain fog is causing forgetfulness, fuzziness, and frustration for New Zealanders trying to return to work after Covid-19.
But the Royal College of GPs says most symptoms resolve within four to six weeks.
"There doesn't seem to be any specific treatment apart from just resting, taking it easy, plenty of fluids, eating well and just building your exercise tolerance over time," the college's medical director Dr Bryan Betty said.
"In the majority of cases, these types of symptoms do actually go."
Long Covid is diagnosed when symptoms last more than 12 weeks.
University of Otago emeritus professor Warren Tate said he was constantly hearing from people worried their lingering Covid-19 symptoms would become long Covid.
"I'm now getting, every day, several emails and phone calls from people you know, desperately asking me, what can they do."
But with such a new virus and evolving variants, he can't give definitive answers.
"It's very scary and very hard to predict. And all I can say is just, [recommend] being sensible, not trying to push yourself back into a normal life again ... and trying to keep the stress levels down."
When Hama McNeill (Tapuika, Ngāti Moko) caught Covid-19, his blocked nose and sore throat went away quickly, but not the mental fatigue.
When he tried to go back to work, he needed to nap multiple times a day.
"My ability to recall short-term, mid-term was just pretty shot. I was forgetting people's names - colleagues I'd been working with for some months. I couldn't come up with any detail. It really knocked my confidence."
The brain fog persisted for a month.
"I seriously thought at one point, 'this is it, this is the next five years of my life. Could this be the new me?'"
The 38-year-old father went to see his GP, and looking back, he thinks his concentration was so poor he should not have been on the road.
He crashed his motorcycle just 30 metres from the clinic on his way home.
"It could have been a lot worse, probably because I was foggy I was going slower, so maybe that was a bit of a help."
Aucklander Anna Thomas, 27, tested positive two and a half weeks ago and has returned to work.
She told RNZ she was finding computer work - writing emails - much harder than before.
"And even when I'm speaking, I speak to large groups. I often can't form sentences properly and I sort of have to stop myself and think about what I'm saying again."
Te Herenga Waka senior research fellow Dr Mona Jeffreys is worried Covid-infected people feel too much financial and social pressure to return to work, before their brain function is restored.
"We know the isolation period has been defined according to when you stop being infectious. But that in no way reflects necessarily impacts on your body and your abilities to get back to normal life.
"Physical work, but also, for a lot of people, the mental energy expenditure, can be the thing that tips you over from being able to fully recover from Covid into the longer-term long Covid, extending many, many months beyond the initial infection.
"But we understand that there are huge pressures on people to pay rent, to pay bills, to pay for food."
Jeffreys is in a team of researchers surveying people infected in 2020 and 2021 about their long-term recoveries. They are still seeking participants for the study, who can find out more details here.