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COVID strain developed in lab less lethal than original virus

October 19, 2022 GMT

CLAIM: Scientists in Massachusetts have developed a more lethal strain of COVID-19 in a lab

AP’S ASSESSMENT: Missing Context. Researchers at Boston University say they created a strain of COVID-19 that was less deadly than the version of the virus first detected in Wuhan, China. The hybrid developed for the experiments was, however, more deadly than the omicron variant that’s now the most prevalent worldwide, which is generally less severe than prior variants.

THE FACTS: Social media users and some news outlets this week are falsely claiming a more lethal strain of COVID-19 was created in a Boston lab.

“Boston University researchers have reportedly claimed to have developed new, more lethal COVID strain in lab that has an 80% kill rate in a non-peer reviewed paper,” wrote one user on Twitter in a post that’s been liked or shared more than 8,000 times as of Tuesday.

“This research must stop immediately,” another Twitter user wrote in a post that linked to a news report repeating the claim.

But researchers with the university’s National Emerging Infectious Diseases Laboratories argue the claims misrepresent the study and its goals.

Ronald Corley, the lab’s director, says critics have unfairly latched onto the 80% “kill rate” of the new strain.

“This was a statement taken out of context for the purposes of sensationalism,” he told The Brink, a university-run website spotlighting BU research.

In the study, which was recently posted online but hasn’t been peer reviewed, researchers created a hybrid of the coronavirus by fusing a specific portion of the omicron variant -- known as a “spike protein” -- to the original strain.

They found their hybrid virus killed more lab mice than the omicron variant, but was less deadly than the original virus. Omicron killed none of the mice, while 80% died from the hybrid strain and 100% from the original virus, according to the study.

Mohsan Saeed, a biochemistry professor at BU and a lead researcher on the study, said in a statement provided by the university that the findings will help scientists understand the role various proteins play in the virus in order to develop better treatments.

Benjamin Neuman, a virologist at Texas A&M University, agreed that critics are unfairly focusing on the hybrid virus’ lethality without comparing it to the original strain.

The current omicron variant has been generally found to be milder than its predecessors, leading to less severe symptoms and fewer deaths, according to the Centers for Disease Control and Prevention.

Neuman also noted the BU study was conducted on a species of mouse particularly vulnerable to the coronavirus.

“The results need to be taken with a big grain of salt,” he said in an email. “With the mice, they are either dead or over the virus in about a week, in contrast to people, where it is a much slower disease.”

Some critics claim the study represents potentially risky “gain of function” research, which university officials dispute.

The term refers to scientific experiments that give an organism a new property or enhances an existing one. In the case of a virus such as COVID-19, that could involve making it more deadly, or giving it the ability to transmit to other species.

The university argues the work did not make the original COVID strain more dangerous but actually created a less dangerous one.

“If at any point there was evidence that the research was gaining function,” the university said in its statement to the AP, “we would immediately stop and report.”

But Steven Luby, research director at Stanford University’s Center for Innovation in Global Health, argued the work should be considered a “gain of function” experiment because it took the original virus strain and made it much more infectious while still retaining much of its high killing power.

The university didn’t respond to the concerns, but in its statement to the AP said the research was reviewed and approved by the Boston Public Health Commission and the university’s institutional biosafety committee, which is made up of scientists and local community members.

The work was also conducted in a biosafety-level 3 facility equipped with decontamination technology, interlocked doors and other protections, BU said.


Associated Press reporter Graph Massara in San Francisco contributed to this story.


This is part of AP’s effort to address widely shared misinformation, including work with outside companies and organizations to add factual context to misleading content that is circulating online. Learn more about fact-checking at AP.