Probability of meeting asymptomatic people on the street

The outbreak of the novel coronavirus pneumonia has been widespread worldwide and has caused tens of thousands of people to die. In the face of this global public health emergency, the public is not only actively preventing and controlling, but also worried about the future trend of the epidemic.
How infectious is asymptomatic infection? When will the turning point of global epidemic come? Will the virus disappear from human society?
Wu Zunyou, chief epidemiologist of China Center for Disease Control and prevention, made a video interview on April 1 to answer questions for the public.
On April 1, Wu Zunyou visited to connect with the European times and the Oriental new newspaper of Japan.
How infectious is asymptomatic infection?
From April 1, the national health and Health Commission began to publish the data of asymptomatic infected persons in the daily epidemic report.
Recently, more and more asymptomatic infections appear, making the public nervous tension again. How infectious is asymptomatic infection? Will it trigger a rebound in the domestic epidemic?
For the above problems, Wu Zunyou analysis said that the asymptomatic infected person’s location is first an infected person, the infected person carries the new coronavirus, which may cause transmission.
But he stressed that the infector’s infectivity depends on the amount of virus. The more viruses are reproduced in the body, the more likely symptoms will appear. There was no symptom, and it was also related to the low virus content. If there is less virus, the risk of transmission will be small.
Previous studies have found that the contribution rate of asymptomatic infection to the second generation of cases is about 2% to 4%, that is to say, the overall contribution rate of asymptomatic infection to the epidemic is very small, less than 5%.
In addition, novel coronavirus pneumonia is not prevalent in the past two weeks, Wu Zunyou said. If there is no home contact or contact with other people, it can be judged that it can not be a asymptomatic infection. In addition, the chance for a person to encounter an asymptomatic infected person on the street is basically zero.
Wu stressed that the global epidemic is on the rise, and the imported epidemic is China’s main challenge now. After the accumulated experience of prevention and control in the past few months, a relatively complete prevention and control system has been established, which enables close contacts to be found in time and tracked and observed.
“We have a set of prevention and control measures, even if there are asymptomatic infections, they are all under control, even if there are individual cases, they will not cause spread.” He said.
Wu Zunyou is a guest of the video interview between China new network and the European times and Japan New Oriental.
When will the turning point of global epidemic come?
Novel coronavirus pneumonia has been diagnosed in 930 thousand cases and 46 thousand cases have died in the world, according to the latest data from Johns Hopkins University.
“In the past five weeks, we have seen an almost exponential increase in newly confirmed cases. The death toll has more than doubled in the past week. The novel coronavirus pneumonia case will break through millions in a few days and 50 thousand people will die. World Health Organization director general Tan Desai said at a press conference on the 1st.
In the face of a large number of confirmed infections, people are most concerned about when the inflection point of the epidemic will appear.
According to Wu Zunyou’s analysis, at present, there are still difficulties in the study and judgment of global epidemic inflection points, which are reflected in two aspects: first, only the number of confirmed cases reported by each country is known at present, but the specific incidence time of these reported patients is not known; second, the measures and policies adopted by each country are different, and the implementation of the policies are also different, so it is difficult to judge the policy measures When does it work.
“It is much more difficult to predict the overall global epidemic than to predict the epidemic situation of a country, but we can also make a basic short-term judgment. In the next week, the epidemic situation is still on the rise in the world.” Wu stressed.