Explained: The three things to know about Long Covid

Long Covid is emerging as a health crisis within a health crisis: so what are we learning about it? Science reporter Jamie Morton explains.

It affects people in more ways than we realise

Nearly two years after a UK archaeologist used a Twitter hashtag to coin "Long Covid" as the chronic, post-viral illness plighting her, scientists are still making troubling discoveries about this constellation of symptoms.

This week, a major UK study revealed some of the strongest evidence yet that Covid-19 infections may cause lasting harm to our brains – particularly in areas linked to smell and memory.

And a month earlier, a US study of 153,000 veterans found heart disease risk increased substantially in the year following an infection - even in less severe cases.

They're just two examples of the lingering impact Covid-19 can have on our bodies.

Scientists have observed how Long Covid - a legacy of perhaps between 10 and 20 per cent of cases - can affect nearly every organ system, having linked post-infection problems to respiratory, neurocognitive, metabolic, gastrointestinal, cardiovascular and mental health disorders.

Given this wide array, it's perhaps not surprising symptoms can range from fatigue, headaches, muscle weakness and a shortness of breath to a loss of smell and cognitive dysfunction.

Although the triggers of Long Covid aren't completely understood, its onset was likely due to a combination of direct effects from infection and indirect effects from the defensive immune response, University of Auckland senior lecturer Dr Anna Brooks said.

"What we do know is that it is a complex, multi-system illness largely driven by dysfunction of the immune, nervous and circulatory systems leading to a spectrum of debilitating symptoms."

A particularly common one, she said, was dysautonomia – or a disruption of "autopilot" functions of our nervous system functions like heart rate, breathing, and digestion.

Importantly, Long Covid could still follow even mild infections with the virus – and affect people of all ages, including healthy young adults and kids.

In a new round-up of evidence of around post-acute effects of Covid-19 in children, a team of researchers, including Brooks, pointed to risk of Long Covid, along with the rare but severe multisystem inflammatory syndrome unique to the virus.

Otago University epidemiologist Dr Amanda Kvalsvig said there was still a big question mark about how rare or common these impacts would be here in New Zealand.

"We can expect impacts to be less severe for children than for adults, but we can also expect that the risk will be spread unevenly in our populations."

Omicron doesn't mean good news

Given cases were only beginning to emerge in the first countries Omicron swept through three to four months ago, it was difficult to know precisely what the variant meant for Long Covid risk.

Still, the sheer size of infections Omicron caused, mattered.

Long Covid can affect people of all ages - including children. Photo / 123RF

Dr Mona Jeffreys, a Victoria University researcher co-leading a major project exploring Covid-19's impact here, put that risk into numbers.

"If, say, 10 per cent of people have Covid symptoms that persist beyond one month, we would expect about 1000 people in Aotearoa New Zealand to be in this group, based on pre-Omicron data," she said.

"Based on current numbers – over 260,000 currently - we will be looking at a huge case-load of people."

While earlier studies suggested vaccination reduced the risk for developing Long Covid, Brooks said there was no data yet to suggest the same for Omicron.

"Although vaccination, especially when recently boosted, has proven protective against hospitalisation and severe illness, we know that Omicron is able to partially evade our immune defence, which means there are much higher rates of symptomatic, or breakthrough infections," she added.

"In fact, we don't often hear the term 'breakthrough' like we did for Delta, given it is now relatively common following exposure to Omicron."

So long as Omicron was rife in our communities, with symptomatic infections common, the risk remained, she said.

"We need widespread awareness: the narrative that Omicron is 'mild' is dangerous and misleading."

She pointed out that the term "mild" inferred fewer deaths and hospitalisations from serious infections – and all largely due to high rates of vaccination.

"Vaccinations are critical but are just one layer of protection, and an imperfect one at that," she said, pointing to waning vaccine immunity and the likelihood of new variants.

"So, emphasis on infection prevention should be maintained to reduce infection transmission through vaccination, mask-wearing and adequate indoor ventilation," she said.

"Even a small per cent of widespread infection is going to lead to a significant health and economic burden."

Prevention is the best treatment

Professor Harvey White, a cardiologist who directs Auckland City Hospital's Green Lane Cardiovascular Research Unit, echoed Brooks' point.

"It is real and anybody can get it. The best way to avoid it is to not get Covid in the first place," he said.

"Don't trivialise getting it, you could have heart attacks or strokes in the future, or brain fog affecting your memory and thinking, or fatigue affecting your ability to work or take part in recreation."

For those who did get Covid-19, experts urged people not to try to power through the infection.

"If we look at the people that are affected by Long Covid, it includes those who have quite mild symptoms with the initial infection, as well as young people and those who are very high-functioning physically and cognitively – like athletes or those who hold down high-powered and stressful jobs," Otago University cardio-respiratory physiotherapist Dr Sarah Rhodes said.

"We think that, if you try to push through with an acute infection, that possibly increases your propensity to develop the persistent symptoms.

"That means resting when you have an infection – even if you're only mildly symptomatic - is a really important thing to take on board."

"We need widespread awareness: the narrative that Omicron is 'mild' is dangerous and misleading," University of Auckland researcher Dr Anna Brooks says. Photo / Supplied

For those who unfortunately did go on to develop Long Covid, there weren't yet any specific treatments.

"Obviously, there are a massive amount of symptoms – more than 200 – but a big one is fatigue," Rhodes said.

"Here, what we really encourage people to do is think about managing their energy levels: that means learning about their energy reserve and recognising how much they've got, so they're not depleting it by doing certain things.

"It also means planning out your day, pacing yourself, and not trying to do more and push through, as this is likely to tip the balance and lead to a crash."

Otago University pain management specialist Dr Bronwyn Lennox Thompson suggested people begin their days with a low level of activity, and very slowly increase it, interspersed with regular planned breaks throughout the day.

"At first you may need to rest before you think you need to, but avoiding a 'boom and bust' cycle of overdoing then having to rest is crucial."

Scientists are still learning about Long Covid - a post-viral condition associated with a constellation of more than 200 symptoms. Photo / 123RF

As well, those with Long Covid should maintain a balanced, healthy diet - and call on friends and family for help when they needed to.

"They may question your motivation because your recovery is slow, and you may question your own motivation," Lennox Thompson said.

"Be prepared to say what it's like for you, but most of all, tell people what you think they can do to help."

Because recovery could be slow and demoralising, she said some might question their mental health and feel low in mood.

"Cultivate some time for yourself, connection with at least one good friend, and consider using a form of meditation or relaxation practice," she said.

"Reach out for counselling or talk therapy if you need it."

Brooks said that, to date, there have been no official channels for support for Long Covid sufferers.

"Access to medical care has been challenging, whereby people with Long Covid regularly report a lack of understanding of the condition or knowledge to assist," she said.

"Notwithstanding, medical management guidelines are still emerging, and we hope that in due course dedicated Long Covid services will be implemented."