Where the Covid outbreak began in News stories

Two studies published yesterday in Science magazine are giving us insight into the roots of the pandemic.

The research, which was previewed in February, has now been peer-reviewed and revised, and concludes that the wet market in Wuhan, China, is the likely epicenter of the emergence of Covid. For more, I spoke to my colleague Carl Zimmer, who covers science.

What did these new studies conclude?

These scientists are arguing that it’s most likely that the pandemic got its start from infected animals in the Huanan market in Wuhan, China. The authors suggest that SARS-CoV-2 arose from bats passing on the virus to some kind of intermediate animal. It could be, say, a raccoon dog. Or it could be other kinds of animals that are sold at wildlife markets. From there, it was passed on to people. When they looked at the earliest cases of Covid, they concluded that the cases centered in the neighborhood around the market.

How did they come to that conclusion?

One study looked at what evidence there was of the presence of the virus in the market. The scientists discovered that there seemed to be a correlation between where the virus was in the market and where wildlife was being sold.

The other study is an analysis of the genomes of viruses from early cases. It concludes that there were at least two different spillovers from some animal host into people. The earliest one happened in mid-November 2019, and the second one happened within days or weeks of that.

They also did some statistical analysis, which led them to conclude that there were not a lot of hidden, undetected Covid cases before December 2019. So they argue that there was most likely an outbreak of SARS-CoV-2 in animals that were being sold at the Huanan market, and people were getting infected more than once — at least twice, maybe more times — with this virus. Then, later in December, it took off.

What does this mean for the lab-leak theory?

The authors of this study do not conclude that their evidence points to a leak from a lab. And people who are advocating a lab leak took place will have to explain all of this research. If the authors of these new studies are correct, then there were at least two spillovers of this virus, both of which were at the Huanan market. So if the virus was in a lab miles away, how did that lead to these patterns that these scientists are seeing?

What are some of the outstanding questions about the origins of the virus?

The ultimate origin of this virus still has a lot of questions around it. But scientists are zeroing in on the kinds of bats that carry these kinds of coronaviruses, and they’re looking at certain areas in China, and in Southeast Asia, that seem to be hot spots for these kinds of coronaviruses.

I recently wrote an article about efforts by researchers who have been looking at bats in caves in northern Laos, and doing surveys of their viruses. In 2021, they found some new species of coronaviruses that turned out to be very closely related to SARS-CoV-2. They’re not direct ancestors, but they are giving us clues about this group of viruses from which SARS-CoV-2 evolved.
https://www.nytimes.com/2022/07/15/science/bat-coronavirus-laboratory-experiments.html?campaign_id=154&emc=edit_cb_20220727&instance_id=67782&nl=coronavirus-briefing&regi_id=97466336&segment_id=99727&te=1&user_id=c059839ea45d1c77063affab8aad1346

What’s next for the search for the virus’s origin?

The W.H.O. has put together a second group to look into Covid’s origins. It’s moving very slowly. The group has a list of things that it wants to know. It wants to get more information about possible viral outbreaks in Wuhan in late 2019 and more information on wildlife, among other things. But that all depends on the cooperation of the Chinese government, and so far there’s not much indication that it will..