How can they isolate cases if people may only have mild conditions

I don't know how they are going to fight this virus without a vaccine and people need to keep their social distancing and self-isolation. I guess this virus was notified to WHO on December 31, 2019. Happy New Year. This reads like a book. Crazy. 

Day 27 drawing in self-isolation. Found on the internet I'm going to have to pay attention to the website to give the person proper credit.