How did Hong Kong, with the largest population density in the world, control the epidemic?

How did Hong Kong, with the largest population density in the world, control the epidemic? When the country is in trouble, everyone is responsible. Hong Kong is an international city, and it is very difficult to prevent and control the epidemic. Western group immunization is more likely to aggravate the epidemic prevention pressure in Hong Kong. I believe that with the strong support of the motherland, Hong Kong will certainly overcome the epidemic, but here we still urge the Hong Kong government to guard against overseas import and domestic transmission, and we must not neglect it ... Ordinary people should develop good living and health habits: wear masks when going out, go shopping less, and try to avoid taking public transport. Try not to go to supermarkets, gather less, and don't go to public places of entertainment. Never travel before the epidemic is completely eliminated. Wash your hands when you go out and go home, change clothes frequently, pay attention to seasonal temperature changes, prevent colds, exercise, eat scientifically and reasonably, and improve your physique and resistance. Pay attention to epidemic information notification and strictly abide by epidemic prevention and control requirements!

I think the fastest way to control the epidemic is to control the source of transmission. The most direct and quickest way to solve the problem is to treat it from the source. Just like cutting off the water pipe to stop the water from flowing everywhere, turn off the valve of the water pipe first. When the water source is cut off, there will be no water in the pipeline and it will not flow everywhere. Similarly, eliminate the source of infection first and kill the virus quickly. Control the route of transmission. Virus infection, like heat transfer, is controlled by conduction and convection, and the effect is remarkable. For example, if the transmission is cut off, don't touch the virus to prevent the virus from touching all parts of the body; Avoid convection, that is, prevent the virus from spreading in the air, disinfect regularly in public places or at home or other places, and wear masks to prevent the virus from inhaling into the human body. In a word, this battle is a matter for the whole Chinese nation, and no one can be immune to it. Only when everyone is United and United, the battle will end in the shortest time and at the shortest speed.