It can be difficult trying to explain this worldwide pandemic to children in a child-friendly way. While it may be tempting to "just not talk about it," children are perceptive and know when something is going on that adults aren't telling them. It is best to share with them the facts in kid-friendly terms in order to start an on-going conversation about the virus, as well as to alleviate any fears they may have that you aren't telling them something. When kids know the facts, it can decrease their anxiety. This cartoon from NPR is an excellent resource for talking to your children and pre-teens about the Coronavirus. It tells them everything they need to know and helps to minimize anxiety.
In addition, when talking with children (and teens too!) about Coronavirus, here's an excellent article from Child Mind Institute with tips on how to handle the topic with their age.