Many coronavirus patients seem to get better at first, then rapidly decline and are overtaken by an overwhelming immune response that causes the body to turn on itself.
This “cytokine storm” was once an arcane phenomenon familiar mainly to rheumatologists who study when and how the immune system’s safeguards fail.
But it has become increasingly clear in the past few months that, at least in a subset of people who have the virus, calming the storm is the key to survival.
At least a dozen candidate drugs to treat the coronavirus rely on this premise. A few devices that purify the blood, as dialysis machines do, are also being tested. One promising drug made by Roche is in several clinical trials, including a late-stage trial in combination with the antiviral drug remdesivir…