This episode was filmed on June 30th, 2020.

If we have more recent updates on the COVID-19 pandemic, we will include them in our playlist. [♪ INTRO]. The COVID-19 pandemic is, well, it's new.

We're less than a year in. So it might seem a bit early to talk about the long-term effects of SARS-CoV-2 infection. But we're already starting to see the ways in which this disease may stick with people, from lasting damage to the lungs to potentially triggering diseases like diabetes and Alzheimer's.

So researchers are calling for vigilance — and more research into this virus's enduring effects. Let's start with the most obvious thing: this virus is a respiratory virus, after all, which causes pneumonia —and that can leave some patients with weakened lungs. In fact, one study, published in March in the journal Radiology, looked at 70 COVID-19 patients and found that nearly all of them still had lung abnormalities when they were discharged from the hospital.

This isn't totally surprising, because other coronavirus diseases like SARS and MERS, as well as respiratory infections like the flu, can have lingering effects in our lungs. But studies are also finding similar damage in patients that had mild or no COVID symptoms. So, a lack of symptoms doesn't guarantee a person won't have lung damage from the virus.

And here's the real worry: this kind of lung damage can sometimes progress to pulmonary fibrosis, or scarring of the lungs. Scars in your lungs aren't quite like scars on your skin. Generally, scars on your skin just give you something cool to talk about at parties.

Lung scarring is a problem because scar tissue doesn't do what lung tissue does. It can't exchange oxygen and carbon dioxide efficiently. Plus, it's not flexible, which your lungs need to be in order to whoosh air in and out of you.

So fibrosis gets in the way of breathing, which can make normal activities really difficult. And, scars being scars, this can take a long time to heal. We don't know exactly how long yet because many people are still in the thick of it.

But that suggests complete healing could take weeks, months, or longer. And, given, what we know from SARS and MERS, that makes sense. Like, one follow-up study of 36 MERS patients found evidence of fibrosis in 12 of them months after the initial infection.

And a study of 78 SARS patients found that some of them had lung lesions when they were infected in 2003 that cleared up by the next year. But a few of them had lung damage show up in chest scans… in 2018. So it seems likely that some COVID patients, especially older ones, will face a lengthy recovery.

And lung damage is just one of the reasons for that. Some doctors are also sounding the alarm about diabetes. Now, it might seem like diabetes and a lung infection have nothing in common.

One is a dysregulation of how the body processes sugars—the other, is a viral infection. But doctors keep seeing diabetes-like symptoms in people infected with the virus, both in patients with and without history of diabetes. Like, one case study, published in June, described a healthy patient in their 30s with no history of diabetes who presented at the hospital with diabetic ketoacidosis, a condition caused by a lack of insulin.

The patient tested positive for SARS-CoV-2 — and doctors blamed the episode on the virus. In another report, doctors noted that they found higher levels of glucose and triglycerides in the blood of patients with more severe cases of COVID-19. This marker, called TyG for short, doesn't for sure mean someone has diabetes, but it is tied to a greater risk.

Researchers don't know exactly why this virus would affect sugar metabolism, but cells in the pancreas do have ACE2 receptors on them—the molecule that the SARS-CoV-2 virus uses to get inside cells. So, it's been speculated that the virus could be damaging cells in the pancreas and interfering with insulin production. The big question, though, is whether these patients will have diabetes for the rest of their lives, or if symptoms will clear up once the virus is gone.

And that's an area of ongoing research. Similarly, doctors are seeing neurological symptoms like headaches, confusion, and sensory disturbances popping up days or even weeks after the initial COVID-19 symptoms, and it's not clear if they're short or long term, either. These may be occurring in one third to one half of hospitalized.

COVID patients, though, which is a lot. Some of these symptoms are almost definitely side-effects from the inflammation the body uses to attack the virus— and that could mean that, once the virus is ousted and the immune system calms down, everything will go back to normal. But neuroscientists say it's also possible that inflammation reaching the brain will trigger or exacerbate the kind of neuronal breakdown that occurs in neurodegenerative disorders.

So, people at risk of diseases like Alzheimer's or already in early stages might end up with more sudden and severe cognitive declines. Even more troubling is that there seems to be increasing evidence that this virus can cross the blood-brain barrier to infect and damage the brain directly. We know that some other coronaviruses can access our brains through the olfactory nerve.

And the loss of taste and smell some patients experience with COVID-19 may be evidence of this virus doing the same. And, if it can get into our brains that way, then it might be able to hide out there for months, years, or even decades, only to flare up again. Though we definitely don't know yet if that will end up being the case.

At this point, we should emphasize that many people with COVID-19 have mild symptoms, or none at all. And most will likely make complete recoveries. But unfortunately, for some, this won't be the sort of thing that's over in a of couple weeks.

And it's good to be aware of the potential for long-term effects, because some people will need care for a long time to come—and we, as individuals and as a society, need to prepare for that. Thanks for watching this episode of SciShow. If you want to support what we do around here, you can become a member of our channel.

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