As usual, the focus has been on past risk, not present and future risk. China has had so many internal quarantines and draconian measures taken over the last 6 weeks, that my LEAST worry would be Chinese athletes coming from China. The risk has now shifted. Given the explosion of cases in Europe and (shortly) in the northwest/west coast of the USA (where there's new evidence the coronavirus has been silently spreading in the community for weeks now), there's probably more issue with European and North American athletes, officials, and visiting public spectators. And if this virus has been circulating under the radar in the NW USA, that means it's almost certainly hopped over into Western Canada as well.
Japan: the Japanese government either cannot or will not do extensive testing, even though there's also plenty of evidence that this virus has been community spreading. They are more focused on preserving the Olympics and taking the position that "no news is good news." I'm not sure about that, but that's a separate topic. I would rank the risk of Japanese spectators traveling to Worlds and spreading this virus as some of the highest risk of all (Japanese athletes, coaches and officials, somewhat less so). Paradoxically, I put more trust in the South Koreans even though they have a lot more official virus cases than Japan....because they are so aggressively testing and the centers of infection are mostly identifiable (churches). You can only find what you test for.
A lot can happen in the next 2 weeks, but right now, I would put the odds of staging Worlds as:
25% Will take place as usual, even with minor inconveniences like temperature checking equipment
25% Will be cancelled entirely
50% Will take place but with severe limitations, such as no public spectators, only athletes, coaches, officials, and media.
In the end, I don't think it's going to be the ISU's call to make.