I wouldn't just say possible, I'd say it's highly likely. We have a lot of diseases, infections, and illnesses that most likely have long term side effects but they're also likely small and poorly observed. I've had other illnesses during my life that I'm confident I never fully recovered from (it's not that the condition is horrible, just that I can tell the difference). I think we give human regenerative ability a bit too much credit. Regeneration is amazing in the big scheme of things but we often don't understand relative regenerative ability compared to baseline production and small variance in functional outcomes.
When star athletes have an injury that's more macroscopic we do expect it to heal but often the athlete can't or doesn't want to return because its higher risk for future damage and it's likely they won't be able to perform at their prior state. With less 'physical' injuries we expect a difference for some reason. Maybe the law of large numbers comes into play and we assume all the diseases and their damage is fully removed and replaced at cellular levels when we often have no idea if that's really occurring at full scale.
Overall, I think this is fine. Medicine doesn't promise full, better than new, recovery so to speak always (at least not from good practitioners). What it does often promise instead is a hope and empirical data of improvement and documented side effects with a lot of probabilities for risk and uncertainty quantification. What I think isn't fine is this notion that recovery is always 'complete.' Its likely, as you point out, we're only observing these sorts of smaller effects with COVID due to the widespread infliction it caused over the population and amount of resources humanity has thrown at it to study it in great detail. I suspect there are many other diseases with negligible fractions of resources for study that have similar unknown consequences.
When star athletes have an injury that's more macroscopic we do expect it to heal but often the athlete can't or doesn't want to return because its higher risk for future damage and it's likely they won't be able to perform at their prior state. With less 'physical' injuries we expect a difference for some reason. Maybe the law of large numbers comes into play and we assume all the diseases and their damage is fully removed and replaced at cellular levels when we often have no idea if that's really occurring at full scale.
Overall, I think this is fine. Medicine doesn't promise full, better than new, recovery so to speak always (at least not from good practitioners). What it does often promise instead is a hope and empirical data of improvement and documented side effects with a lot of probabilities for risk and uncertainty quantification. What I think isn't fine is this notion that recovery is always 'complete.' Its likely, as you point out, we're only observing these sorts of smaller effects with COVID due to the widespread infliction it caused over the population and amount of resources humanity has thrown at it to study it in great detail. I suspect there are many other diseases with negligible fractions of resources for study that have similar unknown consequences.