Half of the confirmed cases in Urumqi are asymptomatic. Is the new coronavirus weaker or more cunning?

“Of the confirmed cases in Urumqi, half of the patients were asymptomatic at first, and half of the patients were asymptomatic at all.” On the evening of August 11, Qiu Haibo, a member of the medical treatment group of the National Health Commission and vice president of the Zhongda Hospital Affiliated to Southeast University, who participated in the epidemic prevention and control and clinical treatment in Urumqi, Xinjiang, said in an interview with CCTV that only about one fifth of the patients with new crown in Urumqi had fever, and even fewer patients showed fatigue. The clinical manifestations were very atypical and light, and the imaging findings were very atypical and light At the time of diagnosis, at least half or two-thirds of Wuhan patients had symptoms of fever, cough, muscle soreness and fatigue.

among the 335 confirmed cases of clustering epidemic in Beijing Xinfadi market, there were only 26 cases of severe and critical illness, and 92.3% of mild and common cases, and the cure rate was 100%.

“it is hard to say that this is indeed a possibility. As the virus mutates, the virus strain weakens. There is such a theoretical possibility, but there is no exact evidence to confirm this point in the academic circle.” Zhang Hongtao, an associate professor of pathology and experimental medicine at the University of Pennsylvania School of medicine, said one possible reason is that the majority of patients with recent outbreaks are young people, and there are similar cases in Singapore. Most of the confirmed patients are young and middle-aged foreign workers, and their serious cases are very few.

Zhang Hongtao said that according to the official notification, the average confirmed cases in Urumqi were 35 years old, and the cases all originated from a gathering social activity. “If we want to prove that it is the weakening of virus virulence that leads to the reduction of symptoms in patients with recent outbreaks, then it depends on whether the mortality rate and the proportion of asymptomatic infected people of the same age group are significantly different from the present ratio. Only after controlling the variables can we say that it is the virus itself.” Zhang Hongtao said that at present, people’s awareness of epidemic prevention and control is generally strengthened, and the opportunities of elderly people to contact the virus are significantly less than that of young and middle-aged people who work and socialize more frequently.

in addition, great changes have taken place in the way patients are diagnosed. Qiu Haibo mentioned that the proportion of asymptomatic infections in Urumqi was relatively high in the early stage. Thanks to the favorable management and control of Urumqi, large-scale nucleic acid testing and screening are very timely. Some nucleic acid positive patients who have not yet developed the disease can be found earlier, including real asymptomatic infections and some patients in the incubation period. Most asymptomatic infections will eventually turn into confirmed cases 。

in Beijing, more than half of the patients were found through active nucleic acid screening. However, in February to March this year, affected by the shortage of medical resources, patients can only be diagnosed as positive when they go to the hospital after symptoms appear.

“there is no need to pay too much attention to whether the new coronavirus is weakened. Even if the virulence is reduced by 90%, the protection work can not be relaxed.” Zhang Hongtao reminded that no matter how the transmission and pathogenicity of the new coronavirus changes, ordinary people should do a good job in protection. From the perspective of the government, we can appropriately and dynamically relax or strictly enforce the prevention and control policies based on the real-time epidemic data of regions, so as to minimize the impact of epidemic prevention and control on social and economic life. “For example, the World Health Organization (who) has updated the guidelines for the removal of isolation. Asymptomatic infected persons can be released from isolation 10 days after nucleic acid test is positive, and do not need to be isolated for 14 days. This reduction can actually reduce a lot of burden for epidemic prevention and control.”

“asymptomatic infection or atypical symptoms cause a very big problem, because if the symptoms are not obvious, patients may stay at home and do not seek medical treatment, which may lead to family aggregation transmission.” Qiu Haibo said that this is also an important reason for the family transmission of the cases in the past two weeks.

Zhang Hongtao said that asymptomatic infected people have a weak ability to transmit the virus. This was the case with the nucleic acid positive woman in Wanda Square in Beijing before, and none of her close contacts were infected. An asymptomatic infected person to a city, if the infection, the infected person will also appear symptoms, can not only lead to asymptomatic infection. Once a patient is diagnosed with symptoms, according to China’s existing detection and control efforts and flow control traceability level, we will soon be able to follow suit, lock in the source and all the infected objects, and then quickly isolate and treat them, which will not cause large-scale transmission.

Zhang Hongtao suggested that, however, basic protection should be done well, especially in autumn and winter, which is also a high incidence season for various respiratory diseases. Wearing masks and reducing aggregation are also very beneficial for the protection of other diseases.

“for students who are about to start school, they should still wear masks in the classroom, but if it is outdoor activities, they can be taken off. If you don’t have a confirmed patient in your city, feel free to breathe the air outside. ” Zhang Hongtao said. Your name will always exist on the Internet