So I'm really going out on a limb trying to estimate how long the restrictions are going to last, but the spreading of the SARS coronavirus is probably the closest analogy we have:
December 8 was probably the first case for the Wuhan virus - so if we shift the SARS graph by two months we get a peak in February and an end of new infections somewhere around May.
So all of Q1 would be impacted.
But, if the Wuhan virus is more contagious than SARS, which it appears to be, then this materially changes the speed of the infection wave.
I'd definitely warn against trying to compare SARS which was stopped early on, against the WuFlu, which appears to spread more easily and possibly won't be stopped.
If we compare to the regular "flu season", we are talking about months:
But regular flu is usually less contagious and spreading stops in the northern hemisphere in the summer, because the conditions to spread it deteriorate.
An extreme case of influenza was the Spanish Flu which spread in 3 waves until herd immunity reduced its effective R0 below the critical threshold:
That took 3 years - but international travel was much slower back then.
Another possible outcome is that if the symptoms are mild the Chinese authorities will let it run its course. In this case the Chinese economy would be less affected.
Does anyone have any idea how long it will take to develop a vaccine and produce it at scale?