Did former CDC director offer a ham sandwich theory of COVID-19? Maybe. Maybe not.

As Robert Redfield awoke Friday morning, he found himself transformed in his TV into a gigantic target of viral scorn.

The former director of the Centers for Disease Control and Prevention (CDC) lifted many expert eyebrows from their microscopes, telling CNN’s Sanjay Gupta he believes the coronavirus responsible for COVID-19 originated in a lab in China. In clips CNN aired from an upcoming special this Sunday (which Gupta dubbed an “autopsy” of the pandemic), Redfield dismissed the possibility that the virus could have evolved sufficiently on its own to have “somehow jumped” quickly from bats to humans.

“I just don’t think this makes biological sense,” Redfield told Gupta, arguing it’s easier to conclude that the virus gained greater efficiency at infecting humans inside a lab.

Many infectious disease experts have expressed confidence that COVID-19 is a zoonotic disease that was in fact transmitted from animals to humans, and insist there is a lack of evidence of a lab origin, accidental or otherwise. Anthony Fauci, President Biden’s chief medical adviser, told reporters Friday that Redfield’s comments were just “an opinion.”

Although Redfield acknowledged that other scientists had different analyses and science would eventually determine the origin of COVID-19, some of those other scientists came down more harshly on the former CDC director. Angela Rasmussen, a self-described “excessively direct virologist” affiliated with Georgetown’s Center for Global Health Science and Security, mocked Redfield for apparently coining the term “zoonot,” a relatively innocuous misuse of the adjective “zoonotic” to describe diseases that transmit from animals to humans:

I think it says a lot about Dr. Redfield’s virology qualifications overall that he just made up a new, more scientastic word for “animal” https://t.co/zPToJzu5lk

— Dr. Angela Rasmussen (@angie_rasmussen) March 26, 2021

Jason Kindrachuk, an emerging virus specialist at the University of Manitoba, went even further with ad hominem attacks on Redfield’s argument against a bat-to-human theory:

I’ve never seen a ham sandwich in a suit sweat but I can imagine his response to “what are intermediate hosts?”

— Jason Kindrachuk, PhD (@KindrachukJason) March 26, 2021

There may be more conventionally scientific reasons to doubt Redfield’s reasoning. Some studies indicate that the novel coronavirus actually did evolve quickly on its own, outside of any lab, and that the virus’s infectiousness in humans is not particularly remarkable:

Another recent paper suggests that SARS-CoV-2 spike isn't even especially good at producing infection of human cells – related viruses are much better. This virus is not optimized in humans. https://t.co/LxGHjqrvNp

— Stephen Goldstein (@stgoldst) March 26, 2021

But some biologists and biosecurity experts have also argued that dismissal of the lab leak theory is premature, and that investigations led by the World Health Organization have not adequately addressed it. (Even Rasmussen has acknowledged that a lab leak was possible.) The danger of studying potentially pandemic pathogens in labs is not a new concern.

Early during the COVID-19 pandemic, the Bulletin published an op-ed by then-Federation of American Scientists president Ali Nouri with the headline, “Let evidence, not talk radio, determine whether the outbreak started in a lab.” Between Redfield’s revelations on CNN and the backlash from his peers on social media, turning down the radio may not be enough.