This is an early retrospective study of 99 patients in a Wuhan hospital. This article was published today by Lancet. The study ended in Wuhan on January 25th.
Compared to an earlier assessment the is one important difference. An earlier study showed a mortality rate of about 3% while this is around 11%.
In this small study, the r0 or "r(naught) measure is meaningless.
As you read this they mention bacterial infections also. While you may not have heard of it, roughly 40% of flu patients also have secondary bacterial infections. This is quite common.