Saturday, May 09, 2020

Covid and Bloodclots?

wired |  As if it weren’t enough that the new coronavirus can steal away your ability to breathe and make your immune system turn against you, now we know this fearsome pathogen can also literally curdle your blood. News of the “bizarre, unsettling” complication—one that’s been killing young and middle-aged patients with Covid-19—made headlines last month. “ It crept up on us,” one doctor told The Washington Post for a story published on April 22. “We are scared,” said another.

Other outlets quickly added to the terrifying coverage. Vox cited a hematologist who called the disturbing new outcome “unprecedented … This is not like a disease we’ve seen before.” AFP described the “mysterious” clotting phenomenon as the coronavirus’s “latest lethal surprise.” The New York Times wondered if it might explain another unexpected symptom seen in patients: swollen, red and purple “Covid toes.” There was coverage of a 41-year-old Broadway star, hospitalized with the virus, who’d had to have his leg amputated due to a clot. Yet for all the seeming strangeness of these cases, it’s stranger still that so many people would be acting so bewildered. In fact, researchers have long known about the link between infectious diseases and blood clotting. There’s even data to suggest a heightened risk of fatal heart attacks—a related complication—among those who get plain old influenza.

The study of disease-induced clotting stretches back more than a century. Writing in 1903, pathologists described the same phenomenon in typhoid fever. Adam Cunningham, an immunologist at the University of Birmingham, notes that many common bacteria, such as Helicobacter pylori and Escherichia coli, have also been associated with an increased risk of blood clots. If this fact has mostly been forgotten, it may be on account of our success at treating such infections. “One of the things that probably made a big difference was the introduction of the antibiotic era, so many of the pathogens didn’t get that severe,” Cunningham says.