The seriousness of the epidemic is mainly due to the rapid mutation of the new coronavirus, infectious and hidden, and the continuous inflow of people from abroad and the normal flow of people at home, so the result is that people are intermingled and crossed, and it is natural and inevitable that the formation of each other's infections. But Beijing's epidemic prevention and control measures are getting better and better, and the number of seriously infected people is gradually decreasing, so Beijing's epidemic is gradually getting better and better.
Beijing's outbreak first infected young and middle-aged workers, then spread through them to older people at home, and then through supermarkets and square dances to the whole society.