Photo taken on May 26, 2021 shows a view of Beijing after rain. (LUO XIAOGUANG/XINHUA)

BEIJING - The possibility of Beijing's first locally transmitted Omicron case being contracted from international mail cannot be ruled out, a local health official said Monday.

Pang Xinghuo, deputy director of Beijing's center for disease control and prevention said they collected 22 environmental samples from the piece of international mail, and the nucleic acid tests all came back positive

The patient received an item of mail on Jan 11 delivered from Canada to Beijing via the United States and the Hong Kong Special Administrative Region. She said that she touched the outside of the package and the first page of the document inside, said Pang Xinghuo, deputy director of Beijing's center for disease control and prevention, at a press conference.

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Pang said they collected 22 environmental samples from the piece of international mail, and the nucleic acid tests all came back positive.

The patient had no travel history in other provinces or cities within 14 days before the onset of symptoms, nor did she have contact with risk groups.

So far, the results of nucleic acid tests of 69 close contacts and more than 810 environmental samples have come back negative except for those collected from her home and workplace, Pang said.

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The new case was reported on Saturday and is confirmed to be caused by the Omicron variant of COVID-19, which has been classified as a member of Clade BA.1.

Gene sequencing found that it was not linked to the same transmission chain as the past infections in Beijing or Omicron variants that recently emerged in other areas of China. It showed high similarity to some virus strains isolated in North America and Singapore in December 2021.