Well, there are two aspects of that, Bob. A great question. For those people who really get seriously ill, namely they are in an ICU, intubated, on ventilation, even if it isn't COVID-19, anyone that goes through that is not going to feel perfectly normal for a considerable period of time.
But there's something else that's going on with COVID-19, and those are individuals who don't necessarily have had advanced disease. They could have been in the hospital, they could have been home in bed for a few weeks, but they had symptomatic disease. What we are finding is that a certain percentage of them -- and we don't know what that is yet because we're doing a larger cohort study, so we are going to be studying this -- anywhere from 25, maybe 30 percent, we think, have what's called a post- COVID syndrome, namely they no longer have virus in them, they can't infect anybody, but it takes them anywhere from weeks to months, and maybe even beyond, to feel perfectly normal. And they have a constellation of symptoms and signs that seem to be consistent when you talk to different people. It's extreme fatigue. It's shortness of breath, even among people who were athletes and were really very well-conditioned, have trouble going up a flight of stairs. They have temperature control problems. They feel chilly. They feel warm. They have sleep disturbances, and some of them describe what's called "brain fog," which is not a particularly appropriate term. But what they really mean by that is that they have difficulty focusing or concentrating.
So, there are these effects that we are concerned about. We are also going to be doing imaging studies to make sure there's not residual inflammation in places like in the heart or in the central nervous system or things like that.
So, we're learning that once you get rid of the virus, in a certain proportion of people, they still cannot necessarily feel normal for variable periods of time, and we're going to be investigating that.