One of the hardest parts of controlling COVID-19 is that it’s very difficult to know if you or someone you know is carrying it asymptomatically. So you might let your guard down, spend time in close proximity to someone else, and help it spread. Testing is useful to curb this issue, but the wait on a test result can still take days. So it’s difficult to say for sure, at any given moment, if you actually have COVID-19 or not.
Image: courtesy Caltech
