By Amy Rogers, MD/PhD
Since the COVID-19 outbreak began in Wuhan, China, rumors have circulated that the SARS-CoV-2 coronavirus was artificially engineered as a bioweapon. Conspiracy theorists took as evidence the existence of a biosafety level 4 (BSL-4, maximum containment) lab in Wuhan.
It is not.
Scientists with an expertise in studying the molecular structures of viral proteins have analyzed SARS-CoV-2, looking for evidence of laboratory manipulation. What they found instead is that nature is more creative than we are.
To quote my favorite line from the movie Contagion, “Someone doesn’t have to weaponize the bird flu. The birds are doing that.”
The scientist-authors of the original paper in Nature cite two pieces of evidence that the new coronavirus was not made in a lab.
The first evidence relates to the “key” that the virus uses to open the “lock” on a human lung cell. This key is a protein on the surface of the virus. Like all proteins, it is a long chain of various amino acids strung together. The new coronavirus has an amino acid sequence that is very similar to viruses from bats and from pangolins, but somewhat different from the original SARS virus at positions that were considered critical for it to work. Yet, when scientists tested the new “key” in a lab, it was unexpectedly adept at opening the human “lock” (as well as the lock on ferrets and cats).
From this, the scientists conclude that no human could have made this virus. Why? Because the virus evolved a new way to interact with the human “lock”, a way that our computer models did not anticipate. Basically, nature designed a solution that no present-day scientist could have devised on their own.
The second evidence that this virus evolved naturally is an absence of telltale signs of laboratory manipulation. When scientists manipulate the genome of a microorganism, they don’t start from scratch. They use some kind of pre-existing genetic template, so to speak, and work from that. No such template is present in SARS-CoV-2. To quote from the paper, “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 know these are not very satisfying arguments to the average person. They will not convince true conspiracy believers because a real appreciation of the data requires either highly specialized technical expertise, or faith in the researchers who have such expertise. As a general microbiologist, I can read and understand the original paper but I don’t have the deep, narrow knowledge to critique the data myself. I have to believe that the authors know what they’re doing.
And I do.