Boston University Researchers Develop COVID Strain With 80 Percent Kill Rate in Mice

University fires back, says some reports on the study are inaccurate

Boston University Researchers Develop COVID Strain With 80 Percent Kill Rate in Mice
A researcher works inside a laboratory during the development of a vaccine in a file photo. (Reithera/Handout via Reuters)
Jack Phillips

Researchers with Boston University have developed a strain of COVID-19 that killed 80 percent of mice infected with it, according to a preprint study released last week, prompting concern and condemnation.

The team of researchers extracted the Omicron variant's spike protein, which they noted has "an unusually large number of mutations." The researchers then attached Omicron's spike protein, which is a structure that allows a virus to bind and invade human cells, to the original COVID-19 variant and dubbed it "Omicron S."

"In K18-hACE2 mice, while Omicron causes mild, non-fatal infection," they wrote (pdf), "the Omicron S-carrying virus inflicts severe disease with a mortality rate of 80 percent. This indicates that while the vaccine escape of Omicron is defined by mutations in S, major determinants of viral pathogenicity reside outside of [Omicron] S."

"We generated chimeric recombinant SARS-CoV-2 encoding the S gene of Omicron in the backbone of an ancestral SARS-CoV-2 isolate and compared this virus with the naturally circulating Omicron variant," the researchers wrote. "The Omicron S-bearing virus robustly escapes vaccine-induced humoral immunity, mainly due to mutations in the receptor binding motif (RBM), yet unlike naturally occurring Omicron, efficiently replicates in cell lines and primary-like distal lung cells."

The researchers noted, however, that mice and human immune systems differ greatly. As a result, if the Omicron-S hybrid were to infect humans, it would be unlikely to be as deadly, they noted, adding that the breed of mice that was used is more dissimilar to humans than other breeds subjected to laboratory testing.

However, when they infected human cells with the Omicron-S variant, they found that it was five times more infectious than the Omicron strain of COVID-19.

'False and Inaccurate'

A statement issued by Boston University on Tuesday said that "this research is not gain-of-function research, meaning it did not amplify the Washington state SARS-COV-2 virus strain (original virus from 2020) or make it more dangerous," adding that some online reports Monday are "false and inaccurate."

"In fact, this research made the virus replicate less dangerous," the university stated.

“The animal model that was used was a particular type of mouse that is highly susceptible, and 80 to 100 percent of the infected mice succumb to disease from the original strain, the so-called Washington strain,” the statement continued. “Whereas Omicron causes a very mild disease in these animals.”

The 80 percent number was "taken out of context for the purposes of sensationalism and it totally misrepresents not only the findings, but [also] the purpose of the study," the statement said.

Nonetheless, the study's publication drew online condemnation and concern.

Dr. Paul Hunter, an expert in infectious diseases at England's University of East Anglia, told the Daily Mail on Oct. 17 that he was concerned about what laboratories are capable of producing.

“The issue is what you’re going to be using [the labs] for. If they’re for diagnostic purposes, then you need them. But I don’t think every country needs a BSL-4," Hunter said, referring to the top level of biosecurity used in laboratories.

“If they start having a dual purpose for research that has offensive military implications, that is the concern,” he said.

And Justin Goodman, the senior vice president of the White Coat Waste Project advocacy group, told The Epoch Times that "mad scientists need to be stopped before they cause another pandemic by recklessly supercharging deadly viruses in wasteful taxpayer-funded animal experiments" and called on researchers to "stop the madness."

There has been widespread speculation that scientists at a laboratory in Wuhan, China, may have contributed to the initial outbreak of COVID-19 in Wuhan. Although Chinese Communist Party officials have officially blamed the emergence of the virus on a wet market in the Chinese city, some U.S. intelligence officials in 2021 said they believe COVID-19 either was created inside the lab or had escaped from the facility.
Jack Phillips is a breaking news reporter with 15 years experience who started as a local New York City reporter. Having joined The Epoch Times' news team in 2009, Jack was born and raised near Modesto in California's Central Valley. Follow him on X: