My primary school aged child was worried about us running out of food and toilet paper. We had a talk about what we would do if we run out of toilet paper and what other people do instead of using toilet paper in other countries. This did worry her a lot but after a lot of discussion and coming up with a list of things she wanted me to get food shopping she calmed down.
Try reducing screen time for children so they are not seeing so much about it
Try reducing your exposure to media coverage of coronavirus, particularly if the information is likely to be misleading, inaccurate or sensationalising. Try restricting yourself to particular sources of key information (e.g. UK Government Response and NHS advice)
Be mindful of what children might be overhearing on the news or from adults and other children, and let children know that they can talk to you about anything they might be worried about.