Long Covid issues continuing to mount

The University of Oxford's Maxime Taquet talked with Sunday Morning on the burdens of long-Covid, including a study he co-authored that has been published in The Lancet with the finding that a third of those who got Covid-19 went on to be diagnosed with long-term health problems.

Increasingly, research is showing the long-Covid problem is even more serious than first thought.

Late last year Taquet joined the show to discuss the lingering impact Covid-19 was having, including the fact one in five survivors went on to be diagnosed with a mental illness within three months of testing positive - insomnia and anxiety were the most common. That number is now closer to one in three.

Taquet's latest research sheds a wider light on how widely the body and brain are both affected by Covid-19.

"We... looked at ... a range of different symptoms which affect their breathing, but also their abdominal systems,  their digestive system, their chest, their throat, their pain. We looked at how common those symptoms were a few months after a Covid-19 diagnosis."

The study gathered data on more than 270,000 patients. It found all demographics were just as likely to be affected, Taquet said, though some groups were more likely to suffer particular symptoms over others.  

"In particular people who have had a more severe Covid-19 illness. Those who experienced delirium or other mind-altering effects while sick with Covid-19 had a much higher risk of developing long-term symptoms.

"Out of all the severity factors that we've looked at, having delirium is by far the [greatest] indicator of severity which leads to the highest risk of long-Covid; it increases the risk by 68 percent."

And "Women for instance, were more likely to suffer headaches after Covid-19, but they were less likely to suffer with breathing difficulties than men were."

Many more Covid-19 patients were left with long-term symptoms than would be expected after recovering from a virus.

"We found across long-Covid symptoms - they were all more common after Covid than after influenza.  And on average they were 1.5 times more common - which on the one hand is staggering- that means there is something specific about Covid," he said.  

"On the other hand it's not ten times more common, and yet we don't talk about long-flu. Some commentators of our paper have suggested that perhaps we should start investigating whether there is such a thing as long-flu which has been overlooked simply because flu has not received as much attention as Covid has."

Taquet said of the symptoms found, anxiety and mood disorders were the most common, and at the 3-6 month point they were found in about 15 percent of people.

While it's long been known that physical illnesses can precipitate mental illnesses, the results were "staggering", and went beyond those with a history of these symptoms or predisposed to them, Taquet said.

"In another study we looked at neurological complications of Covid; one of them is blood clots reaching the brain and affecting the circulation of the blood in the brain and sometimes damaging - sometimes permanently - areas of the brain. And that has been found to affect about 1 in 50 patients after Covid-19."

In patients that had experienced delirium while sick with Covid-19 there was almost a 1 in 10 chance of later having a stroke, Taquet said.

"Other complications that we've looked at are things like brain haemorrhage - bleeding in the brain - which also affects quite a significant minority of patients after Covid-19, and those are very worrisome as well."

This and other research into the effects of Covid-19 suggest there could be an association with dementia.

Taquet said their data showed an increased risk of being diagnosed with dementia, but there are good reasons why the correlation may not be simple.

"It might be that some people had dementia before Covid-19 but that was never diagnosed. They arrived in a hospital to receive attention for the Covid-19, but along the way a clinician might raise a flag saying 'well I think this patient is not quite right from a cognitive point of view'... then later on they receive a diagnosis of dementia.

"But that dementia was there all along, it didn't occur as a result of Covid... but it certainly does show that there is an increased rate of diagnosis of dementia.

"That in itself is important to understand from a service provision point of view.  That means there is going to be more people with a diagnosis of dementia and that is going to create some burden on the healthcare services around the world, so that's important to keep in mind."

But even considering that, Taquet said there were good reasons to think Covid-19 may raise the risk and incidence of dementia.

The number of people diagnosed with dementia after having Covid-19 that didn't require hospitalisation showed a "much higher" incidence of dementia occurring than compared to those who have had flu, Taquet said.

A possible mechanism behind that could be "accelerated brain ageing", he said.

"Those are people that might have developed dementia anyway, but it might have been a few years later.

"That affects them, it affects their family, their loved ones, their carers, and that also affects the health services that need to look after them."

It's still not clear what Covid-19 specifically does to the body to cause the long-term symptoms.

"It's still a mystery, it's not even clear whether one single mechanism is causing it," he said.

"When people have Covid they are at an increased risk of creating blood clots around the body, and in particular in the brain, and those might cause a stroke in the most severe and acute instances, but they might also cause long-standing symptoms that are perhaps less clear cut and more difficult to clearly define and delineate, and those might contribute to some presentations of long-Covid.

"In particular brain fog for instance - that's just a hypothesis, but that certainly is one that is currently being investigated. There might be mechanisms to do with inflammation - we know Covid causes inflammation, we know inflammation can reach the brain, and that can lead to a wealth of symptoms. There's quite a few mechanisms by which Covid might reach the body and the brain in particular, and it's urgent that we figure that out. "

The Oxford team's research indicates that it's not just intensive care capacity in hospitals that could be overwhelmed in the immediate timeframe, but general practitioners, wellness clinics, psychologists and psychiatrists could also be stretched, not to mention the cost of social welfare.

And those who continue to be unwell often present with several symptoms in different systems in the body, requiring assistance from several specialty areas, he said.

He warned that while vaccines are very good at reducing the risk of developing serious Covid-19 or dying from it, the vaccinated can still become sick with Covid-19, and researchers are still finding long-Covid symptoms among them.

"As long as there's Covid there's going to be those consequences."