When two brothers fell critically ill with Covid-19 around the same time in March, their doctors were baffled. Both were young — 29 and 31 years old — and healthy. Yet within days they couldn’t breathe on their own and, tragically, one of them died. Two weeks later, when a second pair of Covid-stricken brothers, both in their 20s, also appeared in the Netherlands, geneticists were called in to investigate. What they uncovered was a path leading from severe cases, genetic variations, and gender differences to a loss of immune function that may ultimately yield a new approach to treating thousands of coronavirus patients.
The common thread in the research is the lack of a substance called interferon that helps orchestrate the body’s defense against viral pathogens and can be infused to treat conditions such as infectious hepatitis. Now, increasing evidence suggests…