As of 2400 hours on 1 February, china had confirmed about 14,411 cases of pneumonia with the new coronavirus infection, and more than 130 confirmed cases had been reported in 23 countries and regions from Asia, North America, Europe, Oceania and South America. As the coronavirus epidemic spreads, some early studies are more clearly depicting how pathogens behave and the key determinants of whether they can be controlled.
The New York Times reported on January 31st that while the virus is now a serious public health problem, the risk is still low for most people outside China. The report goes on to list six key questions about the new coronavirus.
How contagious? Medium-infectious
Scientists estimate that without effective containment measures, patients with the new coronary pneumonia could infect between 1.5 and 3.5 people, which is moderately contagious and roughly equivalent to SARS, the New York Times reported. When compared with other viruses, it is less contagious than pathogens such as measles, chickenpox and tuberculosis that can be transmitted in the air, but larger than AIDS (HIV) and hepatitis, which can only be transmitted through the body fluids of infected persons in direct contact.
Respiratory viruses like this can spread in the air, producing tiny droplets when a patient breathes, talks, coughs or sneezes, the report said. The spread of the disease can be reduced through effective public health measures, such as isolating patients and tracking people they have been in contact with. In 2003, when the global health sector systematically tracked and isolated people infected with SARS, the average number of infections per person fell to 0.4, enough to stop the spread of the epidemic.
Today, health authorities around the world are making great efforts to try to do it again.
What’s the lethality? Mortality rate or much lower than SARS
Mortality is one of the most important factors in determining the lethality of an outbreak.
According to the New York Times, early indications are that the mortality rate for the new coronavirus is significantly lower than that of two other coronaviruses: MERS (MERS), which has a fatality rate of one-third, and SARS (atypical pneumonia), which has a fatality rate of about one-tenth. All three viruses appear to attach to proteins on the surface of lung cells, but MERS and SARS are more damaging to lung tissue.
As of 31 January, fewer than one in four of the confirmed cases of the new coronavirus had died, and many of the deaths were among the elderly with pre-existing conditions.
Dr Allison McGeer, an infectious disease specialist at Mount Sinai Hospital in Toronto who has been involved in the fight against SARS, told the New York Times that there is still a lot of uncertainty about the nature and mechanism of the new coronavirus.
He also said that low mortality rates do not necessarily indicate a low risk of pathogens. Seasonal flu, for example, has a death rate of less than one in 1,000, but in the United States, about 200,000 people are hospitalized each year for the flu, of which about 35,000 die.
How long is the incubation period? About 2 to 14 days.
CDC officials estimate the incubation period for the new coronavirus to be 2 to 14 days. It is not clear whether carriers of the virus can spread the virus before the onset of symptoms, or whether patients with severe symptoms are more likely to spread the virus.
“It worries me because it means that the infected person may have evaded the test. Dr. Mark Denison, an infectious disease expert at Vanderbilt University, told the New York Times.
According to the New York Times, the time required to develop symptoms after infection is critical to prevention and control. This time is known as the incubation period and allows health officials to isolate or observe people who may have come into contact with the virus. However, these measures may be difficult to implement if the incubation period is too long or too short.
If the incubation period is only two or three days, such as influenza, the infected person may spread the virus before the onset of the disease, when it is almost impossible for health care providers to identify and isolate infected people.
The incubation period for sars virus is about 5 days, and the patient is not able to spread the virus four or five days after the symptoms begin. Dr McGill told the New York Times that this gave epidemic prevention personnel time to stop the virus and effectively contain the outbreak.
How difficult is the outbreak to be contained? More difficult transportation hubs
The New York Times points out that the new coronavirus spreads rapidly because it started in Wuhan, a transporthub city, making it more difficult to control the outbreak.
Wuhan has a population of nearly 10 million households and about 5 million migrants, with an average of 3,500 passengers flying direct lying from Wuhan to other countries every day. According to the New York Times, the cities with direct flights to Wuhan were the first to report cases of new coronavirus pneumonia outside China.
Wuhan is also an important transportation hub in China, connected to the whole country by high-speed rail and domestic airlines. It is reported that in October and November last year, nearly 2 million people flew from Wuhan to various parts of China.
When SARS broke out in 2003, Traffic in China was far less developed. In total, China now has four times as many train and plane passengers as it did during the SARS outbreak, according to the New York Times.
In the wake of the outbreak, China has taken unprecedented steps to impose travel restrictions on tens of millions of people living in Wuhan and nearby cities. But Zhou Xianwang, deputy secretary of the Wuhan Municipal Committee and mayor, admitted at a press conference on January 26th that more than 5 million people have left Wuhan because of the impact of the Spring Festival and the outbreak.
“You can’t seal up the bacteria, the virus will always spread. “Georgetown University law professor and director of the Whoe Partnership for National and Global Health Law, Lawrence J. “It (virus) will always come out,” said Lawrence O. Gostin. “
How effective is the response? It’s good for the world.
WHO officials praised China’s positive response to the coronavirus.
“I am very impressed with the strong measures China has taken to respond to the outbreak. China’s strong measures will help not only itself, but the world. “After concluding his visit to China, Tan de Sei said at a press conference in Geneva on January 29.
After the outbreak, Wuhan closed the South China seafood market, which is believed to be the birthplace of the outbreak, live poultry trading across the country has also been suspended, schools closed, holidays extended, tour groups were called off …
Mr Tan said the Chinese government had taken extraordinary steps to stop the cases from being exported, “for which China deserves our gratitude and respect.” “
Meanwhile, on January 30, the World Health Organization declared the new coronavirus outbreak a “public health emergency of international concern” and acknowledged that the risk of the outbreak was beyond China.
At present, several countries have taken measures to check passengers arriving at the airport, as well as early detection and isolation of suspected cases.
How long will it take to develop a vaccine? Or for a year.
The New York Times says it took researchers about 20 months to develop a vaccine that could be used in human trials after the 2003 SARS outbreak. By the time the vaccine was developed, the outbreak had already been effectively controlled. By the time the Zika virus broke out in 2015, researchers had shortened the vaccine development time to six months.
Now, researchers may be hoping to further shorten the time it takes to develop a vaccine. Researchers have studied the genome of the new coronavirus and found proteins that are vital to infection, the report said. Scientists from the National Institutes of Health and at least three companies are working on alternative vaccines.
“If we don’t encounter any unforeseen obstacles, we can conduct a trial within the next three months. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said.
But Dr Fauci also warned that it could be months or even years after the initial trials to prove the vaccine was safe and effective. In the best case, the vaccine may be available to the public after a year.