HistoryDiff

The theory is that SARS-CoV-2 originated outside China and was brought to Wuhan via imported frozen foods and their packaging materials (cold chain). This theory has been actively promoted by the Chinese government and suggests that the virus may not have originated within China.

Chinese researchers have reported multiple cases in which SARS-CoV-2 RNA was detected on the surface of frozen food packaging. In late 2020, clusters related to the handling of imported frozen foods were reported in port cities such as Qingdao and Dalian, which Chinese authorities presented as evidence of cold chain infection. The Chinese Center for Disease Control and Prevention has also published research showing that the virus can remain infectious for long periods in low-temperature environments.

In 2021, the WHO-China Joint Investigation Mission found that introduction via the cold chain was "possible," but assessed the possibility of it being the origin of a pandemic as "very unlikely." WHO Director-General Tedros Adhanom Ghebreyesus said after the report was published that "all hypotheses are still on the table," but expressed concern about China's restrictions on data access.

In the international scientific community, the cold chain theory is widely viewed with skepticism as the origin of the pandemic. The basis for this is that (1) the mechanism by which surface contamination of frozen foods causes large-scale community-acquired infections has not been sufficiently demonstrated, (2) epidemiological analysis of initial cases indicates a localized outbreak in Wuhan, and (3) similar outbreaks originating from cold chains have not been confirmed in other countries. Critics of this theory argue that the Chinese government is politically motivated to distract attention from a possible domestic origin.

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