[urinotherapist]

> First of all, there were many jumps of SARS from animals into humans, over a period of months in which the markets containing infected animals were open.

Can you point me to one or two cases you are talking about, please?

[pcrh]

They may be referring to the study below [0]. This showed that several genetic variants (lineages) of SARS-CoV2 were identified in infected people associated with the market, indicating 1) that the virus was already circulating among people before the epidemic took off, and 2) that there was more than one transmission event.

Note that no comparable data associates SARS-CoV2 with the lab in Wuhan.

[0] The Huanan Seafood Wholesale Market in Wuhan was the early epicenter of the COVID-19 pandemic https://www.science.org/doi/full/10.1126/science.abp8715

>we inferred separate introductions of SARS-CoV-2 lineages A and B into humans from likely infected animals at the Huanan market (38). We estimated the first COVID-19 case to have occurred in November 2019, with few human cases and hospitalizations occurring through mid-December. [...] the evidence presented here that lineage A, like lineage B, may have originated at the Huanan market and then spread from this epicenter into the neighborhoods surrounding the market and beyond.

Edit: Additional study:

[1] The molecular epidemiology of multiple zoonotic origins of SARS-CoV-2 https://www.science.org/doi/10.1126/science.abp8337

>We show that SARS-CoV-2 genomic diversity before February 2020 likely comprised only two distinct viral lineages, denoted “A” and “B.” Phylodynamic rooting methods, coupled with epidemic simulations, reveal that these lineages were the result of at least two separate cross-species transmission events into humans. The first zoonotic transmission likely involved lineage B viruses around 18 November 2019 (23 October to 8 December), and the separate introduction of lineage A likely occurred within weeks of this event.

[ricksunny]

For the rec, comment I'm replying to highlights two simultaneously released papers that both include 4 of the 5 authors of the 2020 paper, Proximal Origins, that is in question by the Nate Silver piece that headlines this HN post. (The 5th author, Lipkin's "view has changed":

"The revelation that the WIV was working with SARS-like viruses in subpar safety conditions has led some people to reassess the chance that SARS-CoV-2 could have emerged from some type of laboratory incident. “That’s screwed up,” the Columbia University virologist Ian Lipkin, who coauthored the seminal paper arguing that covid must have had a natural origin, told the journalist Donald McNeil Jr. “It shouldn’t have happened. People should not be looking at bat viruses in BSL-2 labs. My view has changed.”

quote source: https://www.technologyreview.com/2021/06/29/1027290/gain-of-...

[oneshtein]

Moreover, there are some suggestions[0][1], which points to Wuhan World Military Games as starting point for the pandemic.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7813667/

[1] https://www.washingtonpost.com/opinions/2021/06/23/congress-...

[DiogenesKynikos]

SARS repeatedly spilled over into humans during 2002-2003, until the markets were shut down and the infected animal populations were culled. A review on SARS [0] describes how many independent clusters of SARS popped up over a period of months, spread across different markets in the Pearl River Delta:

> Between November 2002 and February 2003, the first cases or clusters of SARS appeared in several independent geographic locations in the Pearl River Delta region in southern Guangdong, and suggested multiple introductions of a virus or similar viruses from a common source. Several of the early cases were reportedly associated with occupations that involved contact with wildlife, including handling, killing and selling wild animals as well as preparing and serving wildlife animal meat in restaurants (Xu et al. 2004). Moreover, a study of early SARS cases (i.e. those with disease onset prior to January 2003) compared to those identified later in the outbreak found that 39% of early-onset cases were food handlers, whereas only 2%–10% of cases between February and April 2003 were associated with this occupation.

The review goes on:

> It was observed that early cases of SARS occurred independently in at least five different well-separated municipalities in Guangdong Province. The study also found that early patients were more likely than later patients to report living near a produce market, but not near a farm, and nine of 23 (or 39%) early patients were food handlers with probable animal contact.

The review also discusses how many SARS spillover events were not recognized at the time:

> Several studies revealed a higher than normal seroprevalence of SARS-CoV antibodies among wild animal traders. Guan et al. (2003) found that eight of 20 (40%) wild animal traders sampled from a market in Shenzhen, Guandong, in 2004 had anti-SARS-CoV antibodies in comparison to 1 from 20 (5%) vegetable traders from the same market. Yu et al. (2003) analysed serum samples taken on May 4, 2003 from animal traders in three different live animal markets in Guangzhou. Out of 508 animal traders surveyed, 13% had antibodies to SARSCoV; 72% of traders of masked palm civets ( Paguma larvata ) were seropositive. Interestingly, none of the animal traders had SARS or atypical pneumonia diagnosed during the SARS outbreak in Guangdong, suggesting asymptomatic infection by SARS-CoV or a closely related SARS-like coronavirus.

SARS probably spilled over countless times into humans during 2002-2003, because there was a large population of farmed animals that had it, and very little was done to cut off the spillover source for months.

This is a key difference from SARS-CoV-2. This outbreak was detected much more quickly (because of China's experience with SARS), and the very first thing the authorities did was to close the Huanan market and crack down on farms that raise the types of animals that are most likely to be involved in the spillover.

0. https://link.springer.com/chapter/10.1007/978-3-540-70962-6_...