A medical worker takes a swab sample from a resident at a community in Shijiazhuang, Hebei province. (PROVIDED BY TIAN MING/HEBEI DAILY)

SHIJIAZHUANG - North China's Hebei province added four COVID-19 medium-risk areas on Sunday, bringing the province's number of medium-risk areas to 21, the provincial health commission said Sunday.

All four areas are in the provincial capital Shijiazhuang — one in Yuhua district, one in Luquan district, and the remaining two in Qiaoxi district.

So far, 21 areas in Shijiazhuang and the city of Xingtai have been classified as medium-risk areas, while the worst-hit Gaocheng district in Shijiazhuang has been classified as a high-risk area.

40 new cases

Hebei reported 40 locally-transmitted confirmed COVID-19 cases and six asymptomatic cases in the first 10 hours of Sunday, local authorities said.

The "patient zero" of this round of COVID-19 outbreak in Hebei may have been infected before Dec 15, 2020, local health authorities said

All the newly found cases are in the provincial capital Shijiazhuang, and 26 of them were previously asymptomatic carriers, said Xu Jianpei, vice governor of Hebei.

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Since Jan 2, the province has reported 223 locally-transmitted confirmed COVID-19 cases and 161 locally-transmitted asymptomatic carriers.  

The "patient zero" of this round of COVID-19 outbreak in Hebei may have been infected before Dec 15, 2020, local health authorities said.

The conclusion is based on preliminary results of epidemiological investigations, said Shi Jian with the provincial center for disease prevention and control at a press conference.

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After conducting gene sequencing on the positive samples, the center found that the virus strain is from Europe, but is different from the variants recently discovered in Britain or South Africa, Shi said, adding that the work to trace the "zero patient" is still underway.