Chinese scientists have found that the new coronavirus, aka COVID-19, behaves more like influenza than other similar strains of coronavirus such as Severe Acute Respiratory Syndrome (SARS), suggesting it spreads more easily than previously expected.
In one case, a patient had no signs or symptoms even after testing positive for the new coronavirus, raising concerns that asymptomatic transmission is highly possible.
The researchers published their findings in the New England Journal of Medicine, offering new evidence that COVID-19, which has so far killed 2,128 people globally, mostly in China, is not like its close cousin SARS.
Virologist and vaccine researchers with Mayo Clinic Dr. Gregory Poland, who was not part of the study, said, “If confirmed, this is very important.”
COVID-19 seems to affect both the upper and lower respiratory tracts, while SARS causes infections deep in the lower respiratory tract, resulting in pneumonia. Since COVID-19 appears to affect the upper as well as lower respiratory tracts, it is less likely to cause severe pneumonia, but can spread easily like flu.
The researchers examined the nose and throat swabs of 18 patients to measure the amount of the new coronavirus.
One patient had no symptoms at all even though the virus was found at moderate levels in the nose and throat. The remaining 17 patients had increased levels of the virus soon after the symptom appeared, a pattern that is much more similar to flu than SARS.
Dr. Poland said, “What this says is clearly this virus can be shed out of the upper respiratory tract and that people are shedding it asymptomatically.”
The study findings suggest that the new coronavirus is not behaving like SARS even though they are genetically similar.
Immunologist Kristian Andersen at Scripps Research, who was not part of the study, said, “This virus is clearly much more capable of spreading between humans than any other novel coronavirus we’ve ever seen. This is more akin to the spread of flu.” The scientists also said that their findings suggest that controlling COVID-19 will require an approach that is different from what worked during the SARS outbreak.