I am from Hong Kong, basically there are some reasons why coronavirus is not spreading very fast in Hong Kong.
Firstly, they have learned the experience of being hit by SARS back in 2003, when the death toll is up a few hundred case at that time. This time, when the coronavirus hit again, everyone rushed to the street and laid overnight to buy mask and antiseptic washing fluid. The local health centers have advices to avoid contact between local residents and hence they stay home during Lunar New Year . Gatgerings, mass events, workplace and government buildings have all been cancelled or shuttered. All Hong Kongers awareness have been raised immediately to prevent the debacle recurring again. Until now, everyone on streets wears mask and obey to the non-contact principles.
Secondly, there are geographical differences between China and Hong Kong. Despite high influx of visitors into the territory, the two have relatively little intergroup contact than intraland.The political conflicts in the past few months have strengthened the identity as a Hong Konger, many of the residents have not been travelled to mainland China in quite a lot months. ShenZhen also acts as a barrier to stand off the transmission. Further, the border gates are limited to only emergency services and few authoritative persons from China. Most HongKongers have no trust in their government, they are determined to saving themselves from the epidemic.