1. What are the persistent ailments?

Surveys and preliminary research indicate the most commonly reported include fatigue, breathlessness, headache, insomnia, chest pain, joint pain, coughing, loss of taste and smell, intermittent fevers and skin rashes. Less frequently, hearing problems, “brain fog,” mental-health problems and hair loss have been reported, though these have yet to be confirmed by studies. Besides these general symptoms, specific organ dysfunction has been reported, involving primarily the heart, lungs, and brain — even among those whose acute infection led to no discernible symptoms. But the science is still evolving and there’s no consensus yet on a clinical definition for long, or post-acute, Covid.

It probably increases with the severity of the initial bout of Covid-19. For instance, two-thirds of patients who had mild-to-moderate Covid-19 reported at least one persistent symptom 60 days after falling ill, according to a French study that followed 150 non-critical patients from