>They need to prevent panic as much as possible, prevent economic collapse, etc. The response to events like this can be worse than the initial problem.
If this event is half as bad as all the literature out of China is suggesting, panic is the least of our worries. What a responsible government should do is initiate some sort of recommendation for gradual stockpiling of goods - perhaps a lottery just to encourage the majority of people to calmly stock up in turns.
In any case the CDC has already issued warning to prepare for "severe disruption to everyday life." Now it's up to the ignorant population to wake up and realize that this isn't just another flu.
