A researcher at Xi’an Jiaotong-Liverpool University lauds the World Health Organisation’s recent decision to declare the novel coronavirus outbreak a “Public Health Emergency of International Concern.”
“I think what they are doing is right,” says Dr Ying Chen of XJTLU’s Department of Health and Environmental Sciences.
“At the moment, there are already a huge number of cases, mainly in Wuhan and Hubei,” he notes.
“Confirmed novel coronavirus infections have been found in more than twenty countries or regions outside mainland China. There is also evidence of person-to-person transmission in a few countries outside of China.
“As a global community, we need to work together to control this.”
Dr Chen explains that the new coronavirus’ ability to spread relatively rapidly presents a great challenge in controlling it, noting that it spreads faster than the coronavirus that caused SARS, which was active in 2002-2003.
“The disease itself is not as severe as SARS in terms of what is known about the mortality rate – 2-3 percent compared to approximately 10 percent for SARS – but it appears this novel coronavirus is more difficult to control than SARS based on current knowledge of its characteristics.
“Based on preliminary data – and this number could change as more data comes in – we think that on average, the basic reproductive rate of the novel coronavirus is around 2.5.
“That means that each person who has the novel coronavirus is transmitting it to 2.5 people on average. Then each of those people is spreading the virus to another 2.5 people on average, and so on.
“The novel coronavirus spreads very quickly compared to the flu virus, where one person transmits it to about 1.3 people on average.
“It took slightly more than 1 month to reach 6,000 confirmed cases of infection with the novel coronavirus, whereas for SARS it took six months.”
Dr Stephen Pan, also based in the XJTLU Department of Health and Environmental Sciences, adds that a reason the novel coronavirus, 2019-nCoV, can spread so quickly is indicated in the word “novel” in its name.
“Because the 2019-nCoV is a new pathogen, very few people will have natural immunity to it,” he says.
“Therefore, most of the population is potentially susceptible to 2019-nCoV infection.
“When a novel pathogen is introduced into a population that is completely susceptible to infection, transmission can be very rapid if appropriate interventions are not implemented.”
Dr Chen says that another difficulty in combatting the novel coronavirus’ spread is the possibility of people being contagious without knowing it. This can occur either because the virus could be infectious before it causes symptoms or because those people don’t have severe symptoms.
“Unlike the virus that caused SARS, some evidence suggests that this novel virus can be transmitted in the incubation period.
“When viruses can be transmitted before people show symptoms, a disease outbreak is harder to control.
“Further, there is a lot of uncertainty about the length of the incubation period.
“According to a paper recently published in the New England Journal of Medicine, which looked at the early 400-plus cases, on average the incubation period was slightly more than 1 week. But it can be quite different between individuals, ranging from one day to two weeks, or even more.”
“Although many of the patients infected with the novel coronavirus have flu-like symptoms, some symptoms can be very minor and various in a certain proportion of the patients.”
The world must work together to manage this outbreak, Dr Chen says.
"China has taken unprecedented measures to control this concerning outbreak, and now WHO will put additional focus on the global response,” he says.
“We need to put quite a lot of effort, resources and strategy behind controlling the spread of the novel coronavirus, and this is a step in the right direction.”
By Tamara Kaup