Coronavirus: The reasons behind the sudden spike in the number of people infected by the deadly disease in China
A sharp increase in the numbers, with 14,840 people diagnosed, does not mean the outbreak has taken a turn for the worse, says WHO. Most of this was down to Hubei using a broader definition to diagnose people, say experts
As news emerged of coronavirus cases stabilizing in China, its report on Thursday, February 13, bucked that trend. The country diagnosed over 14,840 new infections -- all in a single day, sparking fears that the outbreak had taken a turn for the worse.
But the World Health Organization (WHO) was quick to dismiss those fears. They said the spike was due to a change in how China diagnosed and reported the coronavirus disease or COVID-19.
Earlier, health authorities in China used nucleic acid tests to detect the presence of the virus in the throat or nose swabs of patients. Now, the country has adopted lung scans or CT scans to diagnose the illness. Most of the spike was down to Hubei using CT scans to diagnose people, said Mike Ryan, head of WHO's health emergency program. "This does not represent a significant change in the trajectory of the outbreak," he said.
On the same day, the country reported 242 deaths. "The deaths are quite worrisome, there is an increased number of deaths reported, but if you look overall at the total number of deaths and the total number of cases, the fatality ratio is about the same as it has been - but it is still high, as high as the death rate in influenza," David Heymann, Professor of Infectious Disease Epidemiology from the London School of Hygiene and Tropical Medicine, told BBC.
Using the same method, China reported its cases on Friday, February 14, as well, confirming 5,090 new infections and 121 deaths. Overall, coronavirus has infected over 63, 851 people and killed over 1,380 people in Mainland China.
"That adds a little bit to the confusion because if you are using different testing methods, obviously you will get different results," Dr William Schaffner, Professor at the Vanderbilt University School of Medicine, Nashville, Tennessee, tells MEA WorldWide (MEAWW).
"It is a non-specific method and it is aimed at diagnosing people who have pneumonia," explains Dr Schaffner.
This means that the doctors are counting suspected patients whose CT scans show pneumonia which appears as white opaque patches. "What it represents is fluid in the lung spaces," Paras Lakhani, a radiologist at Thomas Jefferson University, told Business Insider.
Why was it done?
On the positive side, it meant Hubei’s doctors would be able to report cases more quickly because they no longer have to wait for lab confirmation, said Ryan. The idea behind this change, according to a statement by China's National Health Commission, is to speed up treatment for patients and increase their chances of recovery.
Besides, the New York Times reported that doctors were running out of nucleic acid test kits.
“I am not sure why the change was made in Hubei, but it is a very rational change to move from ‘confirmed cases’ to ‘probable cases’ given the limited capacity for laboratory testing,” Benjamin Cowling, division head of epidemiology and biostatistics at the University of Hong Kong, told Quartz. “I do not know whether the 15,000 cases are recent or whether they represent a backlog of “probable cases” that were not tested, I suspect it is the latter,” he added.
Among those confirmed, many would have the disease if lab tests (nucleic acid tests) had been done. But the figures would also include some people who had pneumonia not caused by the coronavirus, Prof Paul Hunter, a coronavirus expert from the University of East Anglia, told the Guardian.
For now, "the best way is, of course, to continue to use the PCR. The CT scan is a less-specific test but it does help identify very sick patients," he adds.