Question: What is the story on these new COVID-related health problems I’m reading about — frequent blood clotting issues and strokes among young people?

Answer: Friendly reminder: I’m not a doctor; while I do have public health training, I do not have medical training. With that important caveat out there, here’s the lay of the land as I currently understand it:

Now that medical professionals have had increased opportunity to treat COVID-19 patients, they are starting to see common themes in terms of illness progression. Those observations beget scientific studies. And in the last two weeks or so, we’re having increased scientific evidence highlighting just how common coagulation disorders in COVID-19 hospitalized patients are. When it comes to the blood clotting issues described in the very informative Washington Post article cited in your question, doctors and scientists are still speculating on why patients are experiencing them. There’s a lot we still don’t know about how our bodies work and our immune systems and inflammatory responses are especially mystifying. One of the hypotheses is that the viral-associated coagulation disorders are caused by the inflammatory response to viral illness, which can “lead to an imbalance of the pro- and anti-coagulant state during viral infections.” This imbalance can make blood unable to coagulate (ex: excessive bleeding as seen in Ebola; called thrombocytopenia) or can make blood too sticky (ex: excessive clotting as seen with COVID-19; called disseminated intravascular coagulopathy (DIC)). The COVID-19 disease is clearly more than just a disease of the respiratory system — it seems to be far more of systemic disease than we originally thought.

Turning our attention to strokes among young people, this is also very likely related to the blood clotting issues. Blood clots in the arteries or the brain — called arterial thrombosis — can cause stroke. And the COVID-19 coagulation disorders we’re seeing include arterial thrombosis. So, this could explain why doctors are seeing increased numbers of COVID-19 patients presenting with stroke. I haven’t read any science on the risk of stroke to SARS-CoV-2 infected young people, but since doctors are taking note, I imagine that we’ll soon see more science on the matter. There’s always something new to learn when it comes to a new, highly contagious virus.