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(Piyal Bhattacharjee / BCCL Delhi)
Despite the fact that the number of people vaccinated around the world has risen significantly in recent months, uncertainties remain about their ability to deal with COVID-19 re-infections – especially those caused by variations and mutations of the novel coronavirus . But now researchers seem to have found a stone that kills all birds, in the form of a vaccine that may protect against all coronaviruses.
Using an innovative approach, researchers Steven L. Zeichner of UVA Health and Xiang-Jin Meng of Virginia Tech have developed what could one day become a universal vaccine for coronaviruses. This vaccine combats not only all current and future strains of COVID-19-causing SARS-CoV-2, but also the coronaviruses that previously threatened epidemics or caused frequent colds.
How can one vaccine fight all coronaviruses?
The vaccine made by Zeichner and Meng has an unusual approach in that it targets a portion of the virus protein called the “viral fusion peptide.” This fusion peptide is essentially universal among coronaviruses; in fact, it has not changed at all or differed in any of the SARS-CoV-2 genetic sequences obtained from thousands of patients around the world. The vaccine’s ability to target this universal part should make it effective against all coronaviruses.
To test its effectiveness, Meng and Zeichner created two vaccines: one designed to protect against COVID-19 in humans and another to protect against Porcine Epidemic Diarrhea Vaccine (PEDV) in pigs. Both diseases are caused by distantly related coronaviruses, which share several amino acids that make up the fusion peptide.
Both vaccines were administered to different groups of pigs, and subsequent analysis revealed that both the vaccine for PEDV and the vaccine for SARS-CoV-2 protected the pigs against the disease caused by PEDV. Although the vaccines could not completely prevent the infection, they successfully protected the pigs from developing severe symptoms. In addition, they also stimulated the pigs’ immune systems to build a much more powerful immune response to the infection.
These observations led scientists to the conclusion that if both PEDV and COVID-19 vaccines were to protect the pigs from diseases caused by PEDV and stimulate the immune system to fight the disease, it is reasonable to think that the COVID-19 vaccine would also protect humans. against serious coronavirus infections.
Further benefits and future steps
Meng and Zeichner chose to study PEDV in pigs because it offered them the advantage of analyzing the performance of a vaccine against a coronavirus infection in the original host, in this case pigs. The other models used to test COVID-19 vaccines study SARS-CoV-2 in non-native hosts such as monkeys or hamsters. The fact that pigs are very similar in physiology and immunology to humans added to the benefit.
While the early evidence shows the vaccine’s effectiveness against all coronaviruses, the researchers insist that additional tests and trials in humans are needed before the vaccine is approved for mass production and use.
Overall, the vaccine development platform designed by Zeichner seems to have ticked all the right boxes, as the vaccine provides a new route to rapidly produce vaccines in existing facilities around the world, and at a very low cost. The vaccine can be mass-produced easily and inexpensively because it is made using an existing, widely used technique that involves genetically modifying the common bacterium E. coli. Vaccines made with this method are called killed whole cell vaccines.
“Killed whole-cell vaccines are currently in widespread use to protect against deadly diseases such as cholera and whooping cough,” explains Zeichner. “Factories in many low- to middle-income countries around the world now make hundreds of millions of doses of those vaccines a year, at $ 1 per dose or less. It may be possible to modify those factories to make this new vaccine. Since the technology is very similar, the costs should also be comparable. “
In addition, the entire process used to make whole cell vaccines – from identifying a potential vaccine target to producing the gene-deleted bacteria that have the vaccine antigens on their surface – can take place in as little as two to three weeks, making them ideal. to be. for responding to a pandemic.
The findings of this study, which are currently under peer review, were recently published in the scientific journal PNAS. They are accessible here.
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