Shruti Mehta, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health. “Looking at people who report they are not able to function in life, we’ve seen about 3 to 5 percent, which is still a large number.[..]My bottom line is, with a potential cost of $2.6 trillion, that’s so big that there’s nothing, no preventive action, that wouldn’t be worth doing to reduce the burden of long-Covid,” Cutler said.”

So I think one in ten being quite seriously affected is about in the right ballpark, if not too conservative.

https://observer.com/2022/05/long-covid-will-have-a-massive-...