During their trip to Wuhan, the WHO researchers notably discovered a dozen different strains already existing in December 2019 in this city of Hubei province.
The origin of the Covid-19 epidemic remains shrouded in mystery. A delegation from the World Health Organization (WHO) traveled to Wuhan, China, hoping to get an early response, but their expedition ended last week in a series of disappointments and frustrations.
If they still believe that the Covid-19 passed from a bat to humans through another mammal, they still do not know where and when the pandemic precisely started.
But their trip to the capital of Hubei province was not in vain: several elements allowed them to conclude that the epidemic was much more widespread than imagined in December 2019 in Wuhan. On the spot, the WHO notably discovered more than a dozen different strains of the virus already existing at this period, reveals to CNN the principal investigator of the mission, Peter Ben Embarek.
Silent propagation
Through the examination of partial genetic samples, scientists at WHO were able to assemble 13 different genetic sequences of the SARS-COV-2 virus for the first time from at least December 2019. This discovery suggests that the virus was already circulating “widely in Wuhan in December”, said Peter Ben Embarek to the American media.
The spread had even “probably started well before December,” adds Professor Edward Holmes, a virologist at the University of Sydney, Australia.
According to the scientist, the virus would have spread for a certain time without being detected, before the explosion in the number of cases at the end of 2019.
In addition, “some genetic sequences come from markets and others do not”, contrary to the initial postulate which established the first source of contamination in a market in the city of Wuhan.
Additional checks needed
But one point tarnishes the theory of the members of the WHO delegation. They requested analysis of 92 suspected cases of Covid-19 – patients who exhibited symptoms and were seriously ill – in October and November 2019. They were tested last January to examine the presence and rate of antibodies. Of these 92 people, 67 agreed to be tested and all tested negative.
For Peter Ben Embarek, these results must nevertheless be qualified because there is no data allowing to know whether the antibodies generated by the infectious disease can remain for more than a year in the body. Additional tests must be conducted to verify their hypothesis.
The more so as these 92 declared cases continue to intrigue the principal investigator of the mission because, geographically, they did not appear in clusters as is common in disease outbreaks. On the contrary, they were spread throughout Hubei province.
“Frustrations”
Many questions therefore remain and WHO investigators have expressed their disappointment at the lack of access to raw data, especially on previous cases of diseases such as pneumonia and influenza.
“There is a set of frustrations but also realistic expectations as to what is doable in a given timeframe,” said Peter Ben Embarek in an interview with AFP.
John Watson, a British epidemiologist on the WHO team, however, ruled out that investigators could “find compelling evidence” and determine exactly where and when the virus passed from animals to humans. It is “very, very unrealistic”.
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