Definitely concerned..... Disney is very conservative when it comes to stuff like this. Meaning that if they have any realistic concern that traveling to Hawaii could expose their guests, and in extension, their brand to the negative consequences of this outbreak, they will definitely consider re-routing. And that would really be too bad. We booked this itinerary specifically for the "island hopping" in Hawaii. I would not be interested in another itinerary.
All that said,
I do not want to scare anyone. The trip is still over 2 months away and a lot can happen between here and there. But rest assured,
DCL is closely monitoring this.