A study by Australian researchers that backed the COVID-19 lab leak theory took over one year to be accepted for publication, reports Yahoo! News.
"We were quite stunned," Dr. Nikolai Petrovsky, an endocrinologist at Flinders University in Australia, told the news outlet. The group's work received what he called a "blanket [of] rejections."
But all that changed last month when Nature Scientific Reports published their paper, "In silico comparison of SARS-CoV-2 spike protein-ACE2 binding affinities across species and implications for virus origin."
Although the findings were based in science, their results were still met with a political bulwark.
Petrovsky and his team used computer models to map which animals the virus may have come from before infecting humans. Proponents of the zoonotic theory have alleged that COVID-19 naturally evolved from bats and spilled over to humans but may have had some stops along the way through some intermediary species.
Throughout most of 2020, that was the prevailing narrative on how the pandemic began, pointing to a wet market in Wuhan.
The Australians modeled how the spike proteins on the virus protrude from its surface and bind to a receptor called ACE2, found on the membrane of human and animal cells.
Their computer model calculated how closely the COVID-19 spike proteins fit into the ACE2 keyhole of different species such as monkeys, snakes, mice, bats and, and of course, humans, along with a host of other species. So if the spike protein had trouble binding to the ACE2 receptor of a species, that species wasn't a good candidate for the virus's origins.
Petrovsky and his co-authors didn't give much credit to the zoonotic origins of the virus relating to bats, as without an intermediate species involved, the virus, in addition, had a low binding affinity to the bat ACE2 receptor.
However, there was a possibility that the virus could have jumped from bats to another species before infecting humans. Still, none of the candidates the Australians tested seemed like a good fit for that role.
"If the animal that bridges between bat and man cannot be found, the zoonotic explanation looks much less likely," David Winkler said, a molecular biologist at the La Trobe Institute for Molecular Science and a co-author of the study alongside Petrovsky.
In addition, researchers tested a pangolin, another candidate that gained notoriety as one that made the jump from animals to humans. But they still came up short. The pangolin coronavirus lacked one key feature of COVID-19 called a furin cleavage site.
“Basically, you would expect a naturally derived virus to be less well suited to attaching to the human ACE2 receptor than the SARS-CoV-2 virus is,” says Dr. Jayanta Bhattacharya, a professor of medicine at Stanford University said. "Or if it is naturally derived, we should be able to find an intermediate virus that infects pangolins or bats about as well as humans.”