US researchers have developed a new lethal Covid strain in a laboratory – echoing the type of experiments many fear started the pandemic.
The mutant variant — which is a hybrid of Omicron and the original Wuhan virus — killed 80 percent of mice infected with it at Boston University.
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 virus might be the most contagious form yet.
It will no doubt surprise many Americans that such experiments continue to go on in the US despite concerns similar studies may have led to the global Covid outbreak.
Covid first began spreading from a wet market in Wuhan, China, about eight miles from a similar high-security virology laboratory that manipulated bat coronaviruses.
Chinese scientists were found to have wiped crucial databases and stifled independent investigations into the facility's links to the pandemic.
In the new research , which has not been peer-reviewed, a team of researchers from Boston and Florida extracted Omicron's spike protein — the unique structure that binds to and invades human cells. It has always been present but it has become more evolved over time. Omicron has dozens of mutations in its spike protein that made it so infectious. Researchers attached Omicron's spike protein to the original wildtype strain that first emerged in Wuhan at the start of the pandemic. The researchers looked at how mice fared under the new hybrid strain compared to the original Omicron variant
Boston University's National Emerging Infectious Diseases Laboratories is one of 13 biosafety level 4 labs in the US
The most dangerous type of research can be carried out in these labs, involving highly infectious viruses such as Covid and Ebola
In biosafety 4 labs, researchers do all experiments in a ‘biosafety cabinet’ — an enclosed, ventilated workspace for handling materials contaminated with pathogens
Full-body, air-supplied pressure suits are worn and workers must change their clothing before entering and shower before leaving
80 percent of mice died from the new man-made Covid strain, while none died from the milder Omicron variant alone, researchers at Boston University's National Emerging Infectious Diseases Laboratories found
In the new research, which has not been peer-reviewed, a team of researchers from Boston and Florida extracted Omicron's spike protein — the unique structure that binds to and invades human cells.
It has always been present in the virus but has become more evolved over time. Omicron has dozens of mutations on its spike protein that made it so infectious.
Researchers attached Omicron's spike to the original wildtype strain that first emerged in Wuhan at the start of the pandemic.
The researchers looked at how mice fared against the new hybrid strain compared to the original Omicron variant.
Writing in the paper, they 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.
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The question of whether the global outbreak began with a spillover from wildlife sold at the market or leaked out of the Wuhan lab just eight miles across the Yangtze River has given rise to fierce debate about how to prevent the next pandemic. New studies point to a natural spillover at the Huanan wildlife market. Positive swab samples of floors, cages and counters also track the virus back to stalls in the southwestern corner of the market (bottom left), where animals with the potential to harbor Covid were sold for meat or fur at the time (bottom right)
Pictured: The Wuhan Institute of Virology, where crucial data was wiped by Chinese scientists
The scientists also looked at the different strains' effect on human lung cells that were grown in the lab.
Covid latches onto human cells with its spike protein, and instructs healthy cells to produce copies of itself.
Scientists measured how many copies each variant caused the health cells to produce.
They found the hybrid strain produced five times more viral particles than the original Omicron.
The scientists admit the hybrid virus is unlikely to be as deadly in humans as it was in mice.
This is because the specific breed of lab mice used are very susceptible to severe Covid disease. Mice and humans also have very different immune responses to the virus.
The lab, at Boston University's National Emerging Infectious Diseases Laboratories, is one of 13 biosafety level 4 labs in the US.
These are labs that are authorized to handle the most dangerous pathogens. There are also facilities in Texas, Atlanta and Manhattan, Kansas.
Experiments at these labs often involve tinkering with animal viruses to advance treatments and vaccines that could be used in a future outbreak.
Work on the live virus that causes Covid must be carried out at a BSL-3 or BSL-4 lab.
In BSL-3 labs, researchers do all experiments in a ‘biosafety cabinet’ — an enclosed, ventilated workspace for handling materials contaminated with pathogens.
The labs also have self-closing doors, sealed windows, floors and walls, and filtered ventilation systems.
In a BSL-4 lab, full-body, air-supplied pressure suits are worn and workers must change their clothing before entering and shower before leaving.
The lab is situated in a separate section of the building and has its own dedicated air supply.
The 'lab leak' origin theory for Covid was initially dismissed as conspiracy at the start of the pandemic in favour of a natural emergence.
But the hypothesis gained momentum following a series of revelations and cover-ups.
Crucial information about the earliest infected patients was wiped from the Wuhan lab's database in late 2019 and one of its staff vanished after coming down with a mysterious flu-like illness.
Have we learned nothing? 40 new biochemical labs that handle dangerous viruses are being built around the world
The Coronavirus pandemic has prompted a global surge in laboratories that handle dangerous viruses — despite concerns Covid may have been the result of the risky experiments.
More than 40 facilities certified as biosafety level 3 (BSL-3) or BSL-4 have either been built or have gone into construction since 2020, predominantly across Asia.
Many countries believe they were caught flat-footed by Covid and want to get ahead of the next devastating outbreak by studying pathogens that pose a threat to humans.
Experiments at these labs often involve tinkering with animal viruses to advance treatments and vaccines that could be used in a future outbreak.
There are currently 63 BSL-4 labs, the highest level of security, across the globe. This is up from the 59 which were in operation or planned last year. Three-quarters are in urban areas. South America and Africa are some of the places lacking access to the labs
But there are widespread concerns that these experiments might actually raise the risk of pandemics — something some experts believe was the case with Covid.
The virus first began spreading from a wet market in Wuhan, about eight miles from the Wuhan Institute of Virology (WIV), a high security biolab that worked with dangerous bat coronaviruses.
Scientists there worked on some of Covid's closest relatives. They were also found to have wiped crucial databases and stifled independent investigations into the laboratory's links to the pandemic.
Professor Paul Hunter, an expert in infection diseases at the University of East Anglia in England, told DailyMail.com he was concerned about what all the new labs would be used for.
'The issue is what you’re going to be using [the labs] for,' he told this website. 'If they’re for diagnostic purposes, then you need them. But I don’t think every country needs a BSL-4.’
He added: ‘If they start having a dual purpose for research that has offensive military implications, that is the concern.’
Russia has set out its proposals for 15 of the maximum security labs and India is aiming for 18 BSL-3 and BSL-4 labs in total. The US is also adding a further highest level biosecurity lab to its existing 12.