I believe that everything will depend on how the most developed countries cope with the epidemic. China has introduced very stringent restrictive measures for its citizens through the military and face recognition systems. This led to a very rapid localization of the virus and its elimination with the help of hospitals. On the example of Italy, we can see that countries are not ready for something like China.
I bet the country Japan have already created a vaccine that could be effective to make the pandemic victims cured. In this case, I highly believe that it is really effective because not to advertise Japan, they are quite absolute in this kind of aspects, their discipline is really serious so there's no doubt that they can actually create something to help cure this pandemic.
So, with that all being said, answering the question how long would this crisis will be, from my speculation, it will be 3-4 weeks, till countries announce positive news concerning this virus.