Here's how Covid-19 can creep into the brain and permanently damage it

When people first started getting sick from Covid-19, doctors thought it primarily affected the lungs. But soon after the world realized the virus had the potential to damage the heart, kidneys, brain and a host of other organs.

More concerningly, a growing population of people who survived infections of the coronavirus were found to have been left with long-lasting injuries to their lungs, heart and kidneys.

As scientists around the world scramble to understand the far-reaching implications this will have on public health, scientific peer review methods have been temporarily sidelined as researchers deem it more important to share their urgent results with the world before it can be confirmed by their peers.

Lasting symptoms

This leads to multiple theories, but little in the way of certainty over whether the long-term effects of Covid-19 are permanent, and why they occur in some people and not others. 

But there’s another concerning group that has found little in the way of answers. Former victims of Covid-19 who survived infection without any trace of physical injury, but are never the same again.

Their symptoms include fatigue, body aches, shortness of breath, difficulty focusing, being unable to exercise, headaches and sleeplessness. Some studies show that nearly 50 per cent of people who ‘recovered’ from the coronavirus are still afflicted by these symptoms three months later. 

It’s a growing dilemma, with the victims finding they’re unable to carry out their responsibilities, return to work or live normally. Dubbed “long-haulers,” their persistent symptoms in spite of the absence of Covid-19 in their bodies is most similar to effects felt by SARS, another disease caused by a coronavirus.

Brain game

Scientists first suspected that Covid-19 could somehow harm the brain early into the pandemic when people started reporting their loss of smell and taste. The virus clearly impacted their nerves.

Some scientists are closer to figuring out why. William A. Banks, a professor of medicine at the University of Washington’s School of Medicine and a researcher published a major discovery in the peer-reviewed journal Nature Neuroscience. His research found that covid-19’s spike protein, similar to the arms of the virus, could cross the blood-brain barrier in mice. 

The blood-brain barrier is crucial to humans, and allows vital nutrients to reach the brain while preventing toxins or pathogens from entering and causing infections, while also protecting the brain from the body’s own immune system.

His findings conclude that Covid-19 can enter the brain. He also warns that the coronavirus’s ‘arms’ detach from the virus and cause inflammation in the brain. As a result, the brain releases cytokines which signal a need for an immune response.

But too much can cause a “cytokine storm”, which is bad news for the infected. In a nutshell, the body’s immune system overreacts in trying to kill the virus, leaving the infected person with brain fog, fatigue, and a host of other cognitive issues.

Banks, who has done extensive work on how HIV crosses the blood-brain barrier, says it’s very similar. This opens up different doors to understanding the weird complications that arise for some after being infected, like sleeplessness.

"We know that when you have the COVID infection you have trouble breathing and that's because there's infection in your lung, but an additional explanation is that the virus enters the respiratory centers of the brain and causes problems there as well," said Banks.

For Banks, the virus should be taken very seriously.

"You do not want to mess with this virus," he warns.

"Many of the effects that the COVID virus could be accentuated or perpetuated or even caused by the virus getting in the brain and those effects could last for a very long time."

More cutting-edge research that has yet to be peer-reviewed has more bad news to share.

Deep risk

A paper published in the Alzheimer’s Association Journal says Covid-19 appears to not only cross the blood-brain barrier but can also cause seizures and psychosis as well as increasing a person’s risk for developing Alzheimer’s disease.

While brain function will return to many recovered people, many will suffer long-term disability, adds Dr. Gabriel de Erausquin, the article’s chief author and a researcher at the Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases in the University of Texas.

A lot of patients released after being hospitalized for covid-19 go off with symptoms traditionally associated with brain-injury says the article’s chief author. This includes “forgetfulness that impairs their ability to function,” giving them trouble with basic things like “organizing their tasks” and “being able to prepare a meal.”

While the rate of long-term brain disorders is low, because the number of people getting infected is so high, a large number of people will struggle with this bizarre side-effect. 

Dr. Avindra Nath of the National Institute of Neurological Disorders and Strokes, has even more concerning findings that have yet to be peer-reviewed.

In a paper published by the New England Journal of Medicine, Dr. Nath reports that after studying the brains of 13 deceased covid-19 victims not only did they discover widespread signs of inflammation and damage, but they also found that “very small blood vessels in the brain were leaking.”

This wasn’t happening evenly throughout the brain either. 

The effect was something like dozens of mini-strokes throughout the brain.

Dr. Nath says this may explain why Covid-19 is affecting blood pressure, heart rates and breathing. Some patients get dizzy when they stand up, or have urinary problems, describes Dr. Nath.

His research ends with a warning. The high levels of inflammation and leaky blood vessels are symptoms that can make you vulnerable to Alzheimer’s disease, which currently has no cure.

As scientists embark on more rigorous studies to get to the bottom of Covid-19’s impact on our brains, it remains to be seen whether we’ll remember this pandemic for its forgetful, impaired victims who’ll continue to live in our memory, even as they’re deprived of theirs.