Giroir was, of course, Trump’s COVID “testing czar” and thus a colleague of Fauci’s inside the administration for a year. He’s also an MD. Which makes this a little more notable than the average Fauci criticism on cable news.

I wish I had the scientific background to assess whether Fauci or Giroir are right about this. As you’ll see in the clip, Fauci insisted last year that the pattern of mutations seen in SARS-CoV-2’s genome was consistent with the virus having had a zoonotic origin, i.e. leaping from an animal to a human being. Nonsense, says Giroir to Fox’s Bill Hemmer: “There was no pattern of mutations that suggest that it went right from an animal in a natural situation to humans — and there’s still no evidence to show that. So that statement was completely wrong.”

Is it? It would be completely wrong for Fauci to have said that the pattern of mutation proves that the virus originated naturally, but all I take him to mean was that the virus looked like what you’d expect a virus to look like if it evolved naturally. That point was echoed in a study of the virus’s genome published last March. One of the study’s authors, Kristian Andersen, turned up in Fauci’s newly released emails, having sent him a message last February suggesting that the virus could have been engineered. But by the time the study was published six weeks later, Andersen had apparently changed his mind:

It is improbable that SARS-CoV-2 emerged through laboratory manipulation of a related SARS-CoV-like coronavirus. As noted above, the RBD of SARS-CoV-2 is optimized for binding to human ACE2 with an efficient solution different from those previously predicted. Furthermore, if genetic manipulation had been performed, one of the several reverse-genetic systems available for betacoronaviruses would probably have been used. However, the genetic data irrefutably show that SARS-CoV-2 is not derived from any previously used virus backbone.

I’ve seen that point made in other arguments about the virus’s origins. Typically a bioweapon would be made by taking an already known virus “off the shelf” and tinkering with its genome to make it more dangerous. SARS-CoV-2 looks sufficiently different from other known viruses that that seems not to have happened here.

Or did it? This excerpt is loaded with jargon but I think “animal passage” refers to gain-of-function research. Either way, Andersen and his co-authors are talking about engineering the virus by propagating it in the lab and letting mutations develop naturally:

In theory, it is possible that SARS-CoV-2 acquired RBD mutations (Fig. 1a) during adaptation to passage in cell culture, as has been observed in studies of SARS-CoV. The finding of SARS-CoV-like coronaviruses from pangolins with nearly identical RBDs, however, provides a much stronger and more parsimonious explanation of how SARS-CoV-2 acquired these via recombination or mutation.

The acquisition of both the polybasic cleavage site and predicted O-linked glycans also argues against culture-based scenarios. New polybasic cleavage sites have been observed only after prolonged passage of low-pathogenicity avian influenza virus in vitro or in vivo. Furthermore, a hypothetical generation of SARS-CoV-2 by cell culture or animal passage would have required prior isolation of a progenitor virus with very high genetic similarity, which has not been described. Subsequent generation of a polybasic cleavage site would have then required repeated passage in cell culture or animals with ACE2 receptors similar to those of humans, but such work has also not previously been described. Finally, the generation of the predicted O-linked glycans is also unlikely to have occurred due to cell-culture passage, as such features suggest the involvement of an immune system.

If I’m understanding that correctly, they’re saying:

1. Yes, certain mutations observed in the virus could have been bred in cell cultures in the lab, but since those mutations look a lot like the mutations seen in viruses in pangolins, it’s more likely that SARS-CoV-2 jumped from a pangolin. The problem is, it’s now 15 months later and China still can’t find a pangolin with the virus in its system.

2. Certain other mutations seen in the virus would have required a lot of breeding in the lab, and would have had to begin with a virus that already looked a lot like SARS-CoV-2. And there’s no evidence that the Wuhan Institute of Virology had a virus like that. Except, per Vanity Fair’s reporting this morning, it turns out the WIV was working with at least two “undisclosed” viruses.

3. To ensure that SARS-CoV-2 was dangerous to humans, scientists would have had to perform gain-of-function progressions in animals with human-type receptors. There was no evidence of Chinese scientists doing that when this study was published. But again, according to Vanity Fair, it appears now that Chinese scientists had engineered mice with “humanized” lungs by the summer of 2019.

What I’m wondering is whether Fauci and Giroir might both be right. Maybe the virus’s mutations are consistent with animal origin and maybe it was developed in a lab. My understanding of gain-of-function research is that scientists take a harmless animal virus, inject it into an animal, then wait to give the virus time to mutate a little bit, as viruses always do when entering a new host. Then they harvest the mutated virus from the infected animal and inject it into another animal, wait for it to mutate slightly again, and then harvest that mutated virus. The process repeats until the constantly evolving virus becomes dangerous to humans — airborne, lethal, transmissible, what have you. By doing this, scientists are “speeding up” evolution to try to anticipate how a harmless animal virus might mutate over time in the wild into something that might cause a pandemic. Then a vaccine can (theoretically) be produced for it before that jump ever happens.

The point is, although the research is taking place in a lab, the mutations that occur in gain-of-function are all “natural,” occurring inside animal hosts. In which case, shouldn’t the mutations in SARS-CoV-2 be consistent with zoonotic transfer from animals to humans if it was produced via gain-of-function and a lab accident? If so, then even if Fauci was right last year, the fact that SARS-CoV-2 “looks like” a virus that evolved naturally tells us nothing about its origins.

I’m open to correction from readers who understand this stuff better than I ever will. Here’s Giroir, who’s notably open to the possibility that this was a bioweapons program gone wrong — although he still thinks an accident involving gain-of-function research is the most likely explanation.