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From Schwartz Media, I’m Ruby Jones, this is 7am.

Scientists researching COVID-19 have discovered that the physical impacts of the virus on the body go far beyond what we might have originally thought.

A new study by Oxford University - involving more than 230,000 people - has linked the virus to neurological disorders, such as stroke and dementia.

The results could have profound impacts for how we respond to and treat COVID-19.

Today, senior reporter for The Saturday Paper Rick Morton, on our growing knowledge of how the virus changes our bodies, and our brains.

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RUBY:

Rick, you've been investigating the possible impacts of COVID-19 on the brain - as if there wasn't already enough to worry about with COVID, but tell me why scientists think that there could be a link between contracting COVID-19 and having long term neurological effects?

RICK:

Well, it really goes back to the Spanish flu, back in 1918, which was one of the deadliest pandemics in human history.

Archival Tape -- Unidentified Reporter #1:

“There was the catastrophe of 1918 when an influenza epidemic swept through our own nation as well as the entire world.”

RICK:

It's estimated to have killed between 20 and 50 million people around the world.

Archival Tape -- Unidentified Reporter #1:

“The battles against disease throughout the centuries have often found a man in the unfortunate position of having to come back to his family only after an infiltrated his community and in much of the population.”

RICK:

You have to remember back then we didn't know almost anything about viruses or pathogens or infections. And we were stunned because as well as causing death and respiratory problems, as the influenza virus can do, doctors also noticed a much stranger condition occurring at the same time called encephalitis lethargica or the sleeping sickness.

Archival Tape -- Unidentified Reporter #2:

“This condition described as ‘the rigidity of insanity’ had previously only been found in schizophrenics and other deeply disturbed mental patients…”

RICK:

And this was a disease that attacked the brain and left patients speechless and unable to move, almost rendering them catatonic.

Archival Tape -- Unidentified Reporter #2:

“...and it seemed to support the view that these patients neither conveyed nor felt the feeling of life; they had become as passive as zombies.”

RICK:

It's estimated over a million people contracted this disease and perhaps half a million died. But even the survivors weren't off the hook.

Archival Tape -- Unidentified Reporter #2:

“Many survivors seemed to recover almost completely and return to their former lives, only to develop the symptoms of a premature Parkinson’s disease some years later.”

RICK:

You know, many of them developed other long term neurological conditions. One of the most common being Parkinson's. So at the time, scientists couldn't find a conclusive link between the influenza pandemic, and these cases of sleeping sickness and Parkinson's. But the fact they basically overlapped suggested that there was some relationship, whether the virus itself was having a neurological impact, or perhaps it had weakened the body's nervous system and made it more susceptible to other diseases.

But since then, there's been this unresolved question of whether viruses that impact the respiratory system could also impact the brain. And when COVID-19 hit, it's something scientists wanted to get to the bottom of.

RUBY:

Okay, so what do we know about that, Rick? Does COVID-19 have any kind of impact on our neurology?

RICK:

Yes, that seems right. But exactly what kind of impact is complicated.

Archival Tape -- Rick Morton:

“Hello Paul how are you?”

Archival Tape -- Paul Harrison:

“Alright thanks, good morning, or good evening”

Archival Tape -- Rick Morton:

“We’ll go with morning, for you I think…”

RICK:

Now, I spoke to Oxford University professor of psychiatry, Paul Harrison, and he said that there was no doubt that COVID-19 is detectable in the human brain.

Archival Tape -- Paul Harrison:

“There is no doubt that the virus is detectable in the brain. It probably spreads primarily through olfactory nerves. It gets up your nose, travels along a nerve and gets into your brain.”

RICK:

Now, Professor Harrison is one of the authors of a groundbreaking new study that examined over 230,000 people who had confirmed COVID-19 infections, to try and understand exactly what the neurological impact is.

RUBY:

And what is the impact, Rick?

RICK:

Well at the headline level, this research makes for astounding reading, and it shows 34% of people in the sample with COVID-19 also developed a neurological or psychiatric disorder within six months of the infection.

RUBY:

So that's a third of people in this study who had COVID-19, who went on to develop some sort of neurological disease?

RICK:

Correct. And this is the largest study of its kind in the world. So this is, as other scientists have said, and certainly Paul himself, this is the evidence that there is a burden of disease beyond COVID-19 itself.

Archival Tape -- Paul Harrison:

“What was new in this paper is that I think these are the first real reliable estimates of how common the neurological syndromes like dementia and stroke, which again, people have reported appeared to be common, but we didn't have any good numbers on it.”

RUBY:

Right. So there seems to be a link, then, between some neurological illness and COVID-19. But what about those neurological syndromes that emerged during the Spanish flu - things like sleeping disease and Parkinson’s? Was there any evidence linking COVID-19 to those illnesses?

RICK:

This is the good news part of this story. So Professor Harrison told me that they didn't find there were any more, you know, it wasn't more common for Parkinson's disease to occur after having COVID. And it was similar for another neurological condition, called Guillain-Barre Syndrome, which is an autoimmune condition that presents with muscle weakness beginning at the extremities.

And we know this because they actually had cohorts of people to test their results against, including those who had an influenza diagnosis and also people who had other respiratory illnesses that were not COVID-19. So when he says that Parkinson's is not more common after COVID-19, that's how we know that.

Archival Tape -- Paul Harrison:

“And in terms of, kind of, things we didn't find that we might have done, we didn't really find there was more Parkinson's after COVID. And that's something, and that condition called Guillian-Barre Syndrome. So there were two neurological syndromes people had worried about, which we really didn't find good evidence for being commoner after COVID than after the other conditions we looked at.”

RICK:

And this was a really robust study, as I just mentioned, he compared the incidence against influenza and other respiratory illnesses.

Now, when you're talking about cohorts that run into the hundreds of thousands, they're going to be people who are diagnosed with conditions like Parkinson's and Guillain-Barre, and that did happen, but in really small numbers, and they were not significantly higher amongst the COVID-19 cohort, but that's kind of the limit of the good news in this study.

And the bad news is that when it comes to other neurological conditions, not only does it look like contracting COVID-19 increases your risk of developing those conditions, but the more severe your response to the virus, the higher the likelihood you will develop a serious neurological condition.

RUBY:

We'll be back in a moment.

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RUBY:

Rick, we're talking about the potential neurological consequences of COVID-19, but I want to get specific, what neurological conditions does COVID appear to increase the risk of?

RICK:

So there are a number of pretty severe and debilitating neurological ailments that did become more frequent with the seriousness of the virus, which tells researchers the virus itself is somehow triggering these secondary diagnoses. Of the 236,000 people in the main study who had contracted COVID-19, more than two percent had an ischemic stroke - which is where a blood clot blocks circulation of blood in the brain and cutting off kind of function in the brain - about half a percent had brain bleed, so they would call that a kind of intracranial haemorrhage - so that's where, you know, a vessel bursts; this is caused by COVID-19. But for patients with the most severe expression of the virus, the incidence for both these conditions rose to almost 10%, and 3.6% respectively, for the ischemic stroke and intracranial haemorrhage.

Nerve disorders were the highest of the total neurological group, with almost 3% of all COVID-19 patients developing these conditions after contracting COVID-19, but the rate was 4.7%, for those who had the most severe cases.
And so a nerve disorder, particularly what they call plexus disorders, is where nerve fibres from the spinal cord branch out into the rest of the body. That's a plexus. And so these nerve disorders, there's something about the virus that either directly attacks these nerve cells or inflames our immune response so much that our own immune cells attack the nerve fibres.

But there's another condition called myoneurologic junction disorder, which is where the motor neuron speaks to a muscle in the body - so that's the neuron that tells your body to move - and this virus attacks that as well. And so there is some link between how we tell our body to move or how we process these signals that are getting screwed up by this virus.

RUBY:

And so do we know, can we definitively say, that COVID-19 is causing these conditions or is it possible that the link isn’t causal - that the virus is making it more likely that people might develop these conditions for other reasons?

RICK:

It's a good question. And, you know, Harrison and the team at Oxford University, the rest of the researchers tried very hard, as he said, to match the COVID-19 group, not only against those control cohorts I mentioned with influenza or other respiratory tract infections, but also for the severity in those control groups. And as he said to me, there is something about the makeup of the virus itself with its spiky crown of thorns and ability to induce this chaotic nervous system response that attacks the human body, which marks it as a particularly efficient wrecking ball in the human body.

Archival Tape -- Paul Harrison:

“Why is it that some people are getting, for example, dementia or psychosis after COVID? Is it the virus? Is it immune? Is it autoimmune?”

RICK:

And, you know, research is still underway as to precisely what parts of the immune system it triggers the most and why some of them might be misdirected.

Archival Tape -- Paul Harrison:

“Until we understand the mechanisms, we really don't know what to do. We're just going to treat people symptomatically, assuming it's like these conditions are in other situations.”

RICK:

We do know, as he said, that it gets into the brain. And there was some study being done at the end of last year, and at the start of this year, about whether the secondary effects of the COVID-19 virus getting into the brain is actually causing parts of our respiratory distress. So the trouble we have breathing is not just that there's an infection, but that it's actually atrophying parts of the brain that control the autonomous breathing system, so that tell you to breathe. That’s why we can breathe when we're asleep. And so these things are really interesting, study questions that are being posed at the moment.

RUBY:

They're also terrifying.

RICK:

Yeah, they are. They are. And, you know, I don't want to lose too much sleep about it, but it is something it's worth knowing, if only because, you know, this is not just about worrying whether you're going to die from COVID-19. It's about worrying whether you're going to get these other things if you get infected.

RUBY:

So is there anything that we can do about this, Rick? What does it mean for the way that we should be responding to the pandemic?

RICK:

Look, you know, knowledge is everything, and at the very least, I mean, we were caught more unawares with Covid-19 than we should have been. You know, Professor Paul Harrison said to me epidemiologists were warning us for years that there was going to be another great zoonotic virus that makes the jump into the human species. And it was only a matter of time. And I keep coming back to this point when I talk about, you know, this whole last year and a half really is that sharing resources and the knowledge of the scientific community, the amount that we've learnt in the last year and a half with a global effort, like a massive, never seen before global effort, is phenomenal. And we're going to need it. And we’re going to need to remember this stuff because there will be another zoonotic pathogen that crosses because we are living closer, as he says, to some species of animal that we should never have really been in contact with in the first place. And it just becomes more likely the more people there are and the more the climate changes, all of these things that, you know, are theoretically within our control, but which are such a runaway freight train at the moment that it's going to happen again.

And so we don't even know if the next pathogen is going to be a Coronavirus. It's likely that it might be, but it could be something new altogether. And so understanding the ways in which viruses generally infect the body and cause these immune responses is a useful first step. You know, developing MRNA vaccines as a platform, an amazing development which has allowed us to, you know, with light speed, kind of get these vaccines to market. So these things are all important. I mean, we should also be developing in vaccination programmes, not just for our own country, but, you know, the Pacific as well. Because, again, we make the point over and over again, this is not just about vaccinating your own. We need global herd immunity and you need to vaccinate everyone in the world - or as many people as you can - to make sure that, you know, it's as safe as possible to get back out there.

RUBY:

Rick, thanks so much for coming in today.

RICK:

Thank you, Ruby.

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RUBY:

Also in the news today:

The jury in the trial of former police officer Derek Chauvin has gone into deliberations after closing arguments were made by the prosecution and defence. Chauvin is accused of murdering George Floyd, who died in Minneapolis last year after Chauvin knelt on his neck and back for nine minutes and 29 seconds.

And, New Zealand's Health Ministry has confirmed an Auckland airport border worker has tested positive for coronavirus.

It comes one day after the trans-Tasman travel bubble began, but both New Zealand and Australian officials have said they do not expect it to shut down quarantine-free travel across the Tasman.

I’m Ruby Jones, this is 7am, see ya tomorrow.

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