Positive COVID-19 cases reported in South China's Guangzhou have been traced to one transmission chain, but patient zero has yet to be found 20 days after the first case was reported, a health official said on Tuesday.
Since May 21, Guangzhou, capital city of South China's Guangdong Province, has recorded a total of 98 confirmed cases, most of whom are patients with mild symptoms, as well as 10 asymptomatic cases.
The genetic sequencing of positive cases discovered in Guangzhou show at least 98 percent similarity, indicating that all positive cases are in the same transmission chain.
New cases are likely to emerge in the future but will be in restricted zones. The risk of spreading the virus to other zones is low, more investigation is needed to identify patient zero.