So far, this novel coronavirus from China (2019-nCoV) appears to be a milder virus than SARS, but that could mean it has the potential to spread further and wider than SARS, researchers argued.
While the virus seems "relatively mild" compared with fellow coronaviruses SARS and MERS, it could potentially spread more easily if infected people are not seriously ill, reported Vincent Munster, PhD, of the Laboratory of Virology of the National Institute of Allergy and Infectious Diseases in Hamilton, Montana, and colleagues.
"The severity of disease is an important indirect factor in a virus' ability to spread," the authors wrote in a Perspective piece in the .
"If infection does not cause serious disease, infected people will probably not go to health care centers. Instead, they will go to work and travel, potentially spreading the virus to their contacts, possibly even internationally," Munster and colleagues added, noting that the virus also needs "efficient human-to-human transmission" for large-scale spread.
As of Jan. 24, 2020, at least 830 cases of novel coronavirus were confirmed in nine countries, including two travel-associated cases in the U.S. But the 26 reported deaths occurred mainly in patients with underlying illness, the researchers said.
On the other hand, they argued that the relative lack of severe disease with 2019-nCoV may make it harder to contain, because contacts and tracing become more difficult.
"Identification of chains of transmission and subsequent contact tracing are much more complicated if many infected people remain asymptomatic or mildly symptomatic," the team wrote. "More pathogenic viruses that transmit well between humans can generally be contained effectively through syndromic (fever) surveillance and contact tracing," such as the case of the Ebola virus, and SARS itself.
Risk of nosocomial spread may also be a key factor with emerging coronaviruses, as was the case for SARS and MERS.
"In addition to the vulnerability of health care settings to outbreaks of emerging coronaviruses, hospital populations are at significantly increased risk for complications from infection [...] Thus, emerging viruses that may go undetected in healthy people can pose a significant risk to vulnerable populations with underlying medical conditions," the authors wrote.
Ultimately, they concluded that a virus that causes less severe disease could have worse implications for population-level health, especially if it proves that it can be transmitted efficiently between people.
"A virus that poses a low health threat on the individual level can pose a high risk on the population level, with the potential to cause disruptions of global public health systems and economic losses," Munster and co-authors wrote. "This possibility warrants the current aggressive response aimed at tracing and diagnosing every infected patient and thereby breaking the transmission chain of 2019-nCoV."
Disclosures
The authors disclosed no conflicts of interest.
Primary Source
New England Journal of Medicine
Munster VJ, et al "A novel coronavirus emerging in China -- Key questions for impact assessment" N Engl J Med 2020; DOI: 10.1056/NEJMp2000929.