I'm intrigued by the first statement: "Recovery [...] appears exponential". If it's exponential, then there's a measurable decay rate. Or you could express it

I'm intrigued by the first statement: "Recovery [...] appears exponential". If it's exponential, then there's a measurable decay rate. Or you could express it as a half life. So what is the half life of COVID after-effects? I scanned the article for mentions of what the decay rate is, but couldn't find it. That's disappointing, maybe they used the word 'exponential' without knowing what it means.