There's a confusion that I'm seeing repeatedly, which is important to get right: Asymptomatic != Presymptomatic. If someone is asymptomatic at the moment you t

There's a confusion that I'm seeing repeatedly, which is important to get right: Asymptomatic != Presymptomatic. If someone is asymptomatic at the moment you test them, that could be either because they will never develop symptoms, or it could mean that you tested them during the disease's incubation period. When talking about a patient at a particular moment in time when you tested them, both of these are referred to as being asymptomatic. When talking about the overall disease course, the former case is called asymptomatic and the latter is called presymptomatic. As tests get better and less scarce, and contact tracing gets better, a larger fraction of cases will be tested when they are presymptomatic. When researchers do studies that screen a bunch of people, especially in populations where the obviously-symptomatic people have mostly already been moved elsewhere, they will find that most of their positives are asymptomatic (at the time of test), and unless they're doing follow-ups, they don't know whether they'll develop symptoms later.