compilation | Feng Lifei
local time on January 31, the "Nature" website released the title "Coronavirus Outbreak: What's Next?" "News interpretation article. In the
report, several experts from all over the world interpreted the best and worst cases of the new crown pneumonia epidemic based on past epidemics and their knowledge.
The following are the main points of the article:
一
How many people will the new crown virus infect?
China has blocked Wuhan, the epicenter of the epidemic, and researchers quickly shared data about the new virus with the World Health Organization (WHO) and scientists around the world.
However, the number of cases has been on the rise. It has surged to more than 9,000 in the past day (as of the time of publication of Nature). The infection cases mainly occurred in China.
Ben Cowling, an epidemiologist at the University of Hong Kong, China, said that in the best case, as control measures begin to take effect, fewer people will be infected.
But looking at it now, it is still too early to judge whether the isolation measures and the widespread use of masks are effective.
At the same time, scientists are particularly worried about new outbreaks outside of China. The virus has spread on a small scale and locally in Vietnam, Japan, Germany and the United States.
However, these countries have quickly isolated infected people. As of January 30, fewer than 100 cases have been recorded outside of China. Is the new
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virus difficult to eliminate?
When a virus continues to spread in a group, it is called endemic.
Varicella and influenza viruses have been circulating in many countries. At that time, the epidemic was controlled by vaccination and isolation of infected people at home.
A big question is whether the new coronavirus is stubborn and difficult to eliminate. If efforts to control it fail, it is likely to become popular.
is the same as flu, which may mean that the new coronavirus will spread every year and cause human deaths before a vaccine is developed.
If the virus will spread through asymptomatic infected persons, it will become more difficult to control its spread, and it will become more likely to spread.
There have been several cases of asymptomatic infections, but it is not clear whether such asymptomatic or mildly symptomatic cases are common, and whether they are contagious or how contagious.
Coronavirus has a crown-like halo (artist drawing). Image source: Khan: "Nature"
University of Queensland, Australia, virologist Ian Mackay said: "We are studying a virus that may be with us for a long time, or even forever." Asymptomatic cases of
make the new coronavirus different It is the coronavirus that causes severe acute respiratory syndrome (SARS).
From 2002 to 2003, the SARS virus broke out on a global scale, but it usually spreads only when the patient's condition is so severe that it requires hospitalization.
Once the epidemic in the hospital is under control, SARS is under control. Mackay said there is no evidence that the virus is still circulating in humans.
Cowling believes that if control measures are effective and the speed of transmission slows down so that no more than one person is infected by each infected person, then the current epidemic may gradually disappear. Will the new
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virus mutate?
Some researchers worry that with the spread of this new type of coronavirus, the pathogen may mutate, spread faster, or be more likely to cause disease in young people.
Currently, the virus hasCauses serious illness and death, but mainly occurs in the elderly, especially those with a history of diabetes and heart disease.
The youngest death reported so far is a 36-year-old man from Wuhan, but he has no known previous adverse health conditions.
Kristian Andersen, an infectious disease researcher at the Lapus Institute in California, is not worried that the virus will become more virulent.
Andersen said that when the virus jumps from one animal host to another (this may be the way the new coronavirus infects humans), there may be a selective pressure to increase its survival rate in the new host, but this There is almost no impact on the transmission capacity of human diseases or viruses. If anything, the impact will be minimal.
A 2018 study of the SARS virus in primate cells found that mutations in the virus during the 2003 outbreak may reduce its toxicity.
MacKay said that researchers have shared dozens of gene sequences of the new coronavirus strain. As the epidemic progresses, a stable supply of these sequences will help reveal its genetic variation. "Unless the sequence is changed, the virus will not change its behavior. We need to see continuous or consistent virus mutation." How many deaths will the new virus cause
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?
The fatality rate of a virus, that is, the proportion of deaths among infected people, is difficult to calculate during the outbreak, because the records of new cases and deaths are constantly updated.
Currently, there are 213 deaths among nearly 10,000 cases of new coronavirus infection, with a mortality rate of 2% to 3%. This is significantly lower than SARS, which causes approximately 10% of the infected deaths.
Currently, there is no effective drug against the new coronavirus.
Two anti-HIV drugs are being tested as a therapy, and they are thought to target a protein that helps coronavirus replicate.
scientists have also discovered other existing drugs for this effect, and several international research groups are working on a vaccine.
Australian National University infectious disease expert Sanjaya Senanayake is worried that if the virus spreads to relatively resource-deficient areas in the world, such as low-income areas in Africa, their health systems will be in trouble.
On January 30, WHO Director-General Tan Desai declared a global health emergency. His main concern is that the epidemic may spread to countries with fragile health systems.
If the virus spreads all over the world, the death toll may be considerable.
Adam Kamradt-Scott, a global health safety expert at the University of Sydney, Australia, said that although the current mortality rate of 2% to 3% is not as high as SARS, it is still quite high for an infectious disease.
The Spanish flu that broke out in 1918 infected about 500 million people, accounting for one-third of the world's population at the time, and killed more than 2.5% of the infected, about 50 million.
However, the new coronavirus may not be so serious because it usually does not infect or cause the death of young healthy people.
related reports:
https://www.nature.com/articles/d41586-020-00236-9
