American scientists have developed a new lethal Covid strain in a laboratory and say the mutant variant — which is a hybrid of Omicron and the original Wuhan virus — killed 80 per cent of mice infected with it at Boston University.
In the new research, a team of scientists from Boston and Florida extracted Omicron’s spike protein — the unique structure that binds to and invades human cells.
The scientists attached Omicron’s spike to the original wildtype strain that first emerged in Wuhan at the start of the pandemic.
When a similar group of rodents were exposed to the standard Omicron strain, however, they all survived and only experienced ‘mild’ symptoms.
The scientists also infected human cells with the hybrid variant and found it was five times more infectious than Omicron.
This suggests the man-made covid virus might be the most contagious form yet.
Writing in the Boston University’s NEIDL Annual report the scientists said: “In…mice, while Omicron causes mild, non-fatal infection, the Omicron S-carrying virus inflicts severe disease with a mortality rate of 80 percent.”
The researchers said it signaled that while the spike protein is responsible for infectivity, changes to other parts of its structure determine its deadliness.
The scientists also looked at the different strains’ effect on human lung cells that were grown in the lab.
They noted that one limitation of their study was the specific breed of mice used, as other types of mice are more similar to humans.
The type of mice used in the study were developed specifically for looking at severe Covid infection, but currently, no mouse model replicates all aspects of Covid in humans.
The lab at Boston University’s National Emerging Infectious Diseases Laboratories, is one of 13 biosafety level 4 labs in the US, special labs that are authorized to handle the most dangerous pathogens. There are also facilities in Texas, Atlanta and Manhattan, Kansas.
