(FILES) In this file photo taken on January 24, 2020, a security guard stands outside the Huanan Seafood Wholesale Market where the coronavirus was detected in Wuhan. - The Huanan Seafood Wholesale Market really was the epicenter of the Covid pandemic, according to a pair of new studies in the journal Science published on July 26, 2022, that claimed to have tipped the balance in the debate about the virus' origins. Answering the question of whether the disease spilled over naturally from animals to humans, or was the result of a lab accident, is viewed as vital to averting the next pandemic and saving millions of lives. The first paper analyzed the geographic pattern of Covid cases in the outbreak's first month, December 2019, showing the first cases were tightly clustered around the market. (Photo by Hector RETAMAL / AFP)

For more than two years, the corona virus has determined all of our lives. For just as long, scientists have been trying to figure out how the outbreak that developed into a global pandemic came about. Two new studies have now identified an animal market in Wuhan, China, as the starting point for the corona pandemic – and thus invalidated the theory of a laboratory accident as the cause.

The investigations showed “that it is simply not plausible that this virus was introduced to the Wuhan market in any way other than through the wild animal trade,” said one of the authors of the two studies, virologist Michael Worobey from the University of Arizona, on Tuesday.

The work was published in the journal Science. Study author Worobey signed an open letter last year calling for the theory of a laboratory accident at the Institute of Virology in Wuhan to be further examined. The knowledge gained since then would have made him rethink, the virologist said. The virus “originated in this market and spread from there”.

Study co-author Kristian Andersen of the Scripps Research Institute said the theory of a lab leak has not been disproved. But it is important to understand “that there are possible and probable scenarios. And that possible is not the same as probable.”

The two studies on the origin of the corona had already been published as advance publications, so-called preprints. After being appraised by independent experts, they are now appearing in the renowned journal “Science”.

The first research analyzed the geographical distribution of the first Covid cases in December 2019, showing that they were closely clustered around the Huanan Animal Market in Wuhan. Some of the first patients who had not visited the market in the recent past lived in the immediate vicinity of the market.

The researchers also analyzed virus samples that they took on the market in January 2020. According to the information, these were concentrated in the southwestern part of the market, where live animals such as foxes and raccoon dogs were sold. Scientists believe bats were the original hosts of the coronavirus. However, the study did not clarify which animal acted as an intermediate host and transmitted Sars-CoV-2 to humans.

The second study carried out a genome analysis of the virus that was detected in the first corona patients. The researchers examined two lineages of the pathogen. They concluded that both jumped from animals in the market to humans in separate events, in November and December 2019. It is unlikely that the virus circulated in humans before November 2019, the scientists wrote.

It is widely believed that bats were the original hosts of the coronavirus. The two studies were also unable to clarify which animal acted as an intermediate host and transmitted Sars-CoV-2 to humans. For the future it is now important to find out where the animals sold on the market came from in order to minimize future risks.

The corona pandemic started in Wuhan at the end of 2019. It was soon speculated that the virus could have escaped in an accident at the institute of virology in Wuhan, where research on corona viruses is carried out. The Chinese government vigorously denies this.

An international team of experts from the World Health Organization (WHO) was only able to visit Wuhan in January 2021. However, the report presented by the experts did not provide any clear results on the origin of the pandemic. At the time, the WHO experts classified the so-called laboratory theory as “extremely unlikely”.

However, doubts and criticism quickly arose about the report and the investigation itself. Many countries have expressed concern that international experts have been denied access to important data in their investigation in China. The Chinese government has so far vehemently rejected further investigations, which were also called for by WHO chief Tedros Adhanom Ghebreyesus.

The WHO now welcomed the publication of the two studies. “It is extremely important that we continue to research the origins of the pandemic to ensure we are better prepared to prevent and contain future outbreaks, epidemics and pandemics,” WHO expert Maria Van Kerkhove wrote on Twitter.

More than two years after the outbreak of the lung disease, a suburb of Wuhan has now been put under lockdown again. After four asymptomatic cases had been identified, over 1 million citizens are now said to be staying at home and public transport has been stopped.