Guest essay by Eric Worrall

Frontline doctors in China have claimed a small Russian strain Covid-19 outbreak in North East China has a longer symptom free infectious period, making it more difficult to detect and contain. But US Epidemologist Keiji Fukuda thinks the apparent change in behaviour is more likely an artefact of rigorous testing, leading to earlier detection.

China’s New Outbreak Shows Signs the Virus Could Be Changing

Bloomberg News 20 May 2020, 16:02 GMT+10 Updated on 20 May 2020, 19:00 GMT+10

Patients in new cluster take longer to show symptoms, recover.
Uncertainty over virus mutation is hindering control efforts.

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“The longer period during which infected patients show no symptoms has created clusters of family infections,” said Qiu, who was earlier sent to Wuhan to help in the original outbreak. Some 46 cases have been reported over the past two weeks spread across three cities — Shulan, Jilin city and Shengyang — in two provinces, a resurgence of infection that sparked renewed lockdown measures over a region of 100 million people.

Scientists still do not fully understand if the virus is changing in significant ways and the differences Chinese doctors are seeing could be due to the fact that they’re able to observe patients more thoroughly and from an earlier stage than in Wuhan. When the outbreak first exploded in the central Chinese city, the local health-care system was so overwhelmed that only the most serious cases were being treated. The northeast cluster is also far smaller than Hubei’s outbreak, which ultimately sickened over 68,000 people.

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“In theory, some changes in the genetic structure can lead to changes in the virus structure or how the virus behaves,” said Keiji Fukuda, director and clinical professor at the University of Hong Kong’s School of Public Health. “However, many mutations lead to no discernible changes at all.”

It’s likely that the observations in China don’t have a simple correlation with a mutation and “very clear evidence” is needed before concluding that the virus is mutating, he said.

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Officials now believe that the new cluster stemmed from contact with infected arrivals from Russia, which has one of the worst outbreaks in Europe. Genetic sequencing has showed a match between the northeast cases and Russian-linked ones, said Qiu.

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Read more: https://www.bloomberg.com/news/articles/2020-05-20/china-sees-signs-new-cluster-carries-virus-longer-than-in-wuhan

Whatever is going on in North East China and Russia, more testing is clearly the key to containing this nasty disease.