I suspect that the majority of people could lose 10% or so of their lung capacity, heart strength, memory, analytical ability, fitness recovery, immune system, etc. without ever noticing. People don't use their bodies to the fullest and they have no idea what they are capable of, so if their maximums dropped a bit, it would be practically asymptomatic.
I thought I was fine after my infection until I tried running some high-intensity intervals (max heart rate), I quickly discovered I was not fine. But non-athletes don't push themselves that hard, and even athletes avoid it.
There's also the fact that the body can compensate for injury in subconscious ways, and it is impossible to separate the impact from the Covid-19 infection from everything else that has changed in the past few years, including the constant impact of aging.
I thought I was fine after my infection until I tried running some high-intensity intervals (max heart rate), I quickly discovered I was not fine. But non-athletes don't push themselves that hard, and even athletes avoid it.
There's also the fact that the body can compensate for injury in subconscious ways, and it is impossible to separate the impact from the Covid-19 infection from everything else that has changed in the past few years, including the constant impact of aging.