(Fight against New Crown Pneumonia) Why is New Crown Virus one of the most difficult viruses to deal with in human history?
China News Agency, Beijing, May 16 (Guo Chaokai) The sudden outbreak of new pneumonia has become an "enemy" facing all mankind. The spread of the epidemic and the strong contagious nature of New Coronary Pneumonia have made New Coronavirus one of the most difficult viruses to deal with in human history.
From the World Health Organization ’s announcement of the New Coronary Pneumonia Outbreak as “PHEIC” that constitutes international concern on January 30, to the WHO ’s Director-General Tan Desai ’s announcement on March 11 that the New Crown Outbreak has constituted a “global The pandemic has spread to more than 200 countries and regions in the world in the past four months. According to real-time statistical data from Johns Hopkins University in the United States, as of 9:00 on May 16, Beijing time, there have been more than 4.53 million confirmed cases of new coronary pneumonia worldwide, and more than 307,000 deaths.
As Zhang Wenhong, director of the Department of Infection of Huashan Hospital Affiliated to Fudan University, said, New Coronavirus is “one of the most difficult viruses to deal with in human history”. “There is no virus in history that is as weird as New Coronavirus. The strong flu is heavier, the spread is stronger than the severe SARS, and it is still carried asymptomatically. "
The new coronavirus is difficult to deal with, first of all, its strong infectivity. In epidemiology, the basic number of infections (R0) is an important indicator to measure the ability of viral infection. It refers to the average number of people who are infected with a certain infectious disease will transmit the disease to other individuals without external intervention. . The larger the R0 value, the more infectious the virus.
On January 23, WHO initially estimated the R0 value of the new coronavirus between 1.5-2.5. As the epidemic spreads, several studies have pointed out that the R0 value of the new coronavirus is higher than expected. A study published on the preprint website medRxiv on February 11 surveyed 8,866 patients from 30 provinces and municipalities in China and found that their R0 was 3.77. A paper published in Science on March 6 estimated that the new coronavirus R0 was 2.57 through a propagation model.
Compared with SARS (Severe Acute Respiratory Syndrome) virus and MERS (Middle East Respiratory Syndrome) virus of the same coronavirus, the R0 value of the new coronavirus is comparable to SARS virus, but it is more infectious than MERS virus. Related studies have pointed out that the R0 value of SARS virus is between 1.1-4.2, most of which are concentrated in the 2-3 interval; while the R0 value of MERS is lower, about 0.3-0.8. The R0 value of general seasonal influenza is about 1.28, and the R0 value of Spanish influenza in 1918 is 1.80. In this way, the extremely contagious nature of the new coronavirus has brought great challenges to the countries of the world in dealing with the epidemic.
Second, the emergence of asymptomatic infections makes the new corona virus more difficult to deal with. In fact, SARS, MERS and typhoid virus and other infectious diseases are not lacking in similar "lurkers", but the proportion of asymptomatic infections in the new coronary pneumonia epidemic is relatively high.
A retrospective study of 115 children with neonatal coronavirus infection in Wuhan Children's Hospital found that the proportion of asymptomatic infections reached 53%. An authoritative journal "Nature" published an article saying that "30% -60% of people infected with the new coronavirus are asymptomatic or have mild symptoms." Harvard University public health scholar Sarah estimates that "40% of the spread of the new coronavirus is asymptomatic."
Wang Guiqiang, director of the Department of Infection, Peking University First Hospital, told China News Service: "There are many asymptomatic people with the new crown virus, which makes people unpredictable." The pathogenesis of the new crown virus has not yet been fully clarified. It is still unknown how much damage the body causes It is easy to cause panic among the people.
Once again, the variability of the new coronavirus makes it unimaginable. An article published in the National Science Review on March 3 pointed out that the new coronavirus has produced 149 mutation points and evolved two subtypes, namely the L subtype and the S subtype. Earlier, researchers from the Xishuangbanna Tropical Botanical Garden and other institutions of the Chinese Academy of Sciences collected genomic data from 93 new coronavirus samples and divided 58 haplotypes into five ABCDE groups, which were later described as the "five major families" of viruses.
From the "five families" to the analysis of the "two subtypes", the mutation of the new coronavirus has attracted everyone's attention. Wang Guiqiang said that the new coronavirus is relatively easy to mutate, and whether the vaccine is still effective after the mutation is still unknown. The most troublesome thing is that the new coronavirus has no special drugs. At this stage, it is still necessary to insist on early diagnosis and early treatment.
The outside world has noticed that although the Chinese epidemic has basically been blocked, the global epidemic is still spreading, and the number of patients diagnosed is still rising. Michael Ryan, WHO health emergency project leader, said on May 13 that the new coronavirus may become an epidemic virus that will never disappear and coexist with humans for a long time like the HIV virus. Prior to this, Wang Chen, vice president of the Chinese Academy of Engineering, and Xu Fujie, a professor at the First Affiliated Hospital of Zhejiang University, also expressed similar views.
Experts pointed out that the key to thoroughly defeating the new coronavirus lies in the vaccine. At present, there are more than 110 new coronavirus vaccine projects in the world, 8 of which have entered clinical trials, and half of them are from China. Gao Fu, director of the Chinese Center for Disease Control and Prevention, said that in September this year, China may have a new crown vaccine for emergency use.
It is worth noting that when the vaccine will actually be put into use is still unknown. In the face of one of the most difficult viruses in human history, countries around the world still need to prepare for a long-term battle with the new coronavirus. (Finish)