Scientists React to Claims COVID First Emerged in October 2019

Experts have reacted to a study suggesting that the first case of COVID-19 arose between early October and mid-November 2019 in China.

The authors of the study—published on Thursday in the open-access journal PLOS Pathogens—used a novel method for their analysis, repurposing a mathematical model that was originally developed for conservationists to determine the date of extinction of a species, based on recorded sightings.

In the latest paper, the authors instead used the model to determine the date when COVID-19 most likely originated in more than 200 countries and territories around the world, according to when some of the earliest known cases occurred in these areas.

The analysis led by David Roberts—from the University of Kent in the U.K.—and colleagues gives a range of early October to mid-November for China's first case, with the most likely date of origin being November 17.

The authors also estimated that the first case outside of China occurred in Japan on January 3, 2020, while the estimated first case in Europe likely occurred in Spain on January 12, 2020. In addition, they estimated that the first case in North America occurred in the United States on January 16, 2020.

As the COVID-19 pandemic continues, questions regarding its origin still persist, although evidence has been mounting that the first cases occurred earlier than the record of confirmed cases suggests. Officially, the first confirmed cases of the disease were identified in December 2019, in China.

Mark Cameron, an associate professor at the Case Western Reserve University School of Medicine, in Cleveland, Ohio, who was not involved in the latest study, told Newsweek: "The scientists used publicly available 'Worldometer' data to rewind the tape, so to speak, to a time when the first COVID-19 infections are estimated to occur in China in late 2019."

"We've suspected for months now that the virus was causing infections in China earlier than first proposed—specifically the notion that the virus emerged in December in Wuhan seafood markets. Studies since have shown that hospital traffic increased in Wuhan in the weeks or months prior to December, 2019, and scientists tracing the 'family tree' of COVID-19 put its most recent ancestor emerging earlier than December as well."

Cameron said the timeline described in the study appears to hold up throughout COVID-19's global spread beyond China, which lends credence to stories of atypical pneumonias showing up earlier in countries around the world well before their first wave.

"The more we study COVID-19's likely earlier spread around the world, the more we will be able to predict next time, and the better prepared we will be in nipping the next emerging virus in the bud," Cameron said. "Suffice it to say, this study further supports how quickly COVID-19 spread and gained pandemic status."

Robert Garry, a professor of microbiology and immunology at Tulane Medical School in New Orleans, Louisiana, who was also not involved in the latest study, said the paper applies a new mathematical analysis to information pulled from the scientific literature.

"It is perhaps a more refined way to look at some of the data from early cases," he told Newsweek.

David Robertson, head of viral genomics and bioinformatics at the MRC-University of Glasgow Centre for Virus Research in the U.K., said in a statement: "Roberts and colleagues' method from ecological modelling is giving similar timings for the first human to human transmission of SARS-CoV-2 that were published in Science last year."

"So while there is nothing very new in the PLOS Pathogens paper the ecological model Roberts and colleagues use corroborates this sophisticated evolutionary analysis, which would tend to suggest their method is reasonable."

Ben Neuman, chair of biological sciences at Texas A&M University-Texarkana, said the study is one of many attempts to pinpoint the origin time and country for SARS-CoV-2, the virus that causes COVID-19.

"This study is more remarkable for the application of an unusual mathematical model to the limited data on early cases of COVID-19, than for its conclusions, which are roughly in line with those of other studies that focused on the accumulation of mutations in the virus genome," Neuman said in a statement.

"It looks as though any way you slice it, the first case was around November, somewhere in China. This study does not pinpoint the location of the first case within China, or identify any previous hosts of SARS-CoV-2-like progenitor viruses. To answer those questions, we certainly need more genetic data on similar viruses, wherever they may be found."