What are effects of COVID-19 (Corona Virus) on our health?

Well, it’s the week...who even knows of quarantine, and you’ve probably already read every article and could find about the coronavirus. Most of those have focused on what coronavirus is doing to our society, our economy, and our lungs. But as a neuroscientist sitting here in at home, what I’m most curious about is:

What is it doing to our brains?

By now we’ve all got the symptoms of COVID19 memorized: dry cough, fatigue, and a fever. You might even know about some of the more obscure symptoms, like a sore throat, diarrhoea, and aches and pains. We’re learning more every day about this virus, and working out new ways to combat it in our communities. Most of what we hear about the effects of COVID19 is about what it can do to our respiratory system. The SARS-CoV-2 virus, which is the official name of the virus itself, seems to enter the body via the nose or mouth, binding onto cells using the cell surface receptor called angiotensin-converting enzyme 2, or ACE2. The virus injects its genetic material, called RNA, into the cells and hijacks their machinery to make more copies of itself, which go on to attack more cells. Eventually, the virus can make its way down the throat to the lungs, where it takes up residence and wreaks even more havoc. In the tiny air sacs where oxygen gets absorbed into the bloodstream, called the alveoli, the fight between your immune system and the virus can cause inflammation, cell death, syndrome, or ARDS when their lungs are so clogged up that their bodies aren’t able to absorb enough oxygen and they really struggle to breathe. This is usually when a person ends up requiring ventilation to support their breathing – and even that doesn’t always work. But the danger isn’t only to your lungs - it's to your whole body, including your brain. 

 

As the number of COVID19 cases climbs, doctors and scientists have noted more and more symptoms linked to the central nervous systems – severe headaches, for one, and loss of sense of taste and smell for another. more reports include seizures and strokes, and a recent case report even identified a COVID19 a patient suffering from acute necrotizing hemorrhagic encephalopathy, where the Inflammation in her brain led to memory loss and disorientation. So what’s going on here? Well, again, since SARS-CoV-2 is a new virus, we’re not entirely sure. A lot of this hinges on whether or not the virus can cross the blood-brain barrier. Because the brain is so fragile and easily damaged, it’s evolved a special set of blood vessels that are extra-effective at keeping most things, like foreign pathogens, out of the brain. It’s called the blood-brain barrier and you can watch a whole video we made on that by clicking in the corner or check out the description.

 So the blood-brain barrier is great for preventing infection, but also bad for getting drugs into the system to treat any infections that make it through. Case studies on patients have found conflicting evidence as to whether or not SARS-CoV-2 can cross the blood-brain barrier, but some preliminary research in China seems to indicate that it can. And like anything that causes inflammation in the brain, that’s bad news bears. Inflammation in the brain can cause a whole host of problems, most notably swelling, or encephalitis. That swelling puts pressure on the brain, causing everything from mild, flu-like symptoms and headaches on up to seizures, hallucinations, paralysis, and loss of consciousness. Viruses like the flu or other coronaviruses can also kill brain cells called oligodendrocytes, which wrap around neurons and act as insulation to help them send signals. When oligodendrocytes die, this results in demyelination of neurons, which can lead to muscle weakness, vision problems, pain, and changes in sensation, among other things. Viral infections can also activate the brain’s immune cells, called microglia, and make them attack the brain’s healthy tissue when they shouldn’t be. So can SARS-CoV-2 do all of that? Well...we don’t know. We’re still trying to get a handle on what, exactly, this virus does to the body, and to the brain. So far, it doesn’t seem like neurological issues are /primary/ warning signs of a SARS-CoV-2 infection, but some case reports indicate that these symptoms, especially headaches, can show up days before the dry cough or fever, meaning they might be good indicators for when a patient should be isolated and tested for the virus. But, even if SARS-CoV-2 doesn’t primarily attack the brain, that doesn’t mean we won’t see a wave of psychiatric and neurological issues following this pandemic.

 

Researchers at UC San Diego published a paper in April of 2020, just a couple of months after the pandemic began, to warn the scientific and medical community that patients who have been exposed to or recovered from COVID19 should be carefully monitored for neurological issues going forward. Based on past influenza pandemics, like the one in 1918, they say that we should be on the lookout for possible increases in cases of insomnia, anxiety, and depression, in addition to the risks we’ve already mentioned. And all of this doesn’t even touch on the ways in which physical isolation, the anxiety of living in a pandemic, worrying about our loved ones and our health, and the stress of financial uncertainty can all independently cause serious mental strain. We’re still learning what the long term effects of this virus will be - and not just on our brains, but on...everything. But this isn’t all doom and gloom! Thanks to technology, we’re better connected with each other than we ever have been in the past; we’re able to FaceTime with our grandmas, play video games with our friends, and swap favourite sourdough recipes with our internet communities.

There have been some incredible acts of generosity and kindness, and sharing our vulnerabilities and fears can help get them out in the open, giving our support system a chance to prop us up when we need it most. If you’re having a hard time with social distancing, Micah made a video not that long ago about how to better deal with it. Please, please take this virus seriously. It’s a very scary and stressful time, and it’s understandable that we’re all feeling impatient for things to go back to normal. I’m sad that I don’t get to spend time on the beach, or visit with my friends, or go camping or hiking. But I know that this virus is very real and very dangerous, and I’ll stay at home to protect myself and those around me. I hope you will, too. How are you doing, Brainiacs? What have you been spending your time on? If you’re one of the cool people still watching, drop a comment with your favourite sourdough recipe...or any bread recipe I suppose! Just comment something about bread. That’ll really confuse everybody else. Thanks for watching this episode! Until our text transmission.

 Regards

Tahir Mehmood