Thread by @thiagoarzua

Less than a year later, and unfortunately, it's time for a sobering update on all the ways in which COVID-19 can affect the brain - from strokes to long COVID.

As usual, refs at the end, but here it is:

COVID-19 and the brain 🧠: an updated thread 🧵

COVID did infect hundreds of millions of people, giving scientists plenty of data. At the same time, it completely changed how science is done.

A rapidly mutating virus would already be hard to study, the pandemic didn't help. That all to say: There's a lot we still don't know.

Let's start with the survivors. A study published yesterday in The Lancet showed that 33% of patients diagnosed with COVID had some neurological manifestation.

Some key conditions: stroke/bleeding, anxiety and mood disorders, Guillain-Barré syndrome, dementia, and Parkinsonism.

The incidence of stroke and bleeding brings a key point: is the virus causing this, or is it the inflammation caused by the virus? Both.

SARS-CoV-2 does affect brain cells, but a lot of the damage might also come from our own immune system's response, below a summary (Jan/2021).

This brings us to the Post-Acute Sequelae of SARS-CoV-2 infection (PASC) AKA Long COVID.

Symptoms include: fatigue, brain fog, sleep disorders, anxiety, and depression.

At this point, we just don't know enough about it, but the societal impacts of PASC are downright scary.

Speaking of scary, let's talk about a somewhat unspoken population of COVID patients, children.

Although most are spared from the severity of the disease, there's evidence for an increased risk of multisystem inflammatory syndrome (MIS), with a significant neurological impact.

This is still a rare hyperinflammatory condition, but a study showed that up to 12% of children and adolescents hospitalized because of COVID developed life-threatening neurological disorders.

If nothing else, let this be yet another reminder to be safe, no matter your age.

If there are unknowns about the effects of COVID in the brain of pediatric patients, in the pregnant population that's even more nebulous, albeit still concerning.

Although relatively rare, vertical transmission, i.e. mom to baby, of SARS-CoV-2 is possible (around 2-3%)

What remains to be studied is how that early exposure to COVID might affect brain development.

Here, much like PASC and MIS, the research will be ongoing for decades, examining not just the impact of COVID itself, but also the impact of growing up during a global pandemic.

The goal of this is not to be alarmist, but to show some of the effects of this pandemic directly on our brains - and we didn't even touch on mental health yet.

Even with the incredible vaccines we have, this is far from being over. So continue to take care and stay safe y'all.

References: docs.google.com/document/d/1o1…