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Scientists have successfully tested a new vaccine candidate on animal subjects that could provide protection against all existing and future coronavirus variants.
The new vaccine is based on vaccine antigen technology developed by researchers from the University of Cambridge and a biotech company, Diosynvax Ltd.
All SARS-CoV-2 virus variants have spike proteins on their surface, which allows them to enter and infect host cells. Currently available vaccines target these spike proteins but can offer protection against only past virus variants.
This is because the spike proteins keep on changing as the virus undergoes mutation. So, by the time a vaccine targeting a specific spike protein becomes available, a new variant of the virus with a new spike protein emerges.
Unlike currently available vaccines, the new vaccine candidate targets those vital sections of the virus that it requires to complete its life cycle. “This approach allows us to have a vaccine with a broad effect that viruses will have trouble getting around,” said Jonathan Heeney, lead researcher and head of The Laboratory of Viral Zoonotics at Cambridge.
COVID-19 was not the first major illness caused by the SARS (severe acute respiratory syndrome) virus. The first SARS outbreak was reported in China’s Guangdong Province in 2002. It was responsible for causing the first pandemic of the 21st century, infecting over 8,000 individuals in 29 countries.
Since the first outbreak (and after the coronavirus pandemic), numerous SARS-Cov-2 viruses and their variants freely flow between animals and human bodies. You never know when one of them turns into a threat to humans.
“In nature, there are lots of these viruses just waiting for an accident to happen,” Heeney said. “We wanted to come up with a vaccine that would not only protect against SARS-CoV-2, but all its relatives,” he added.
They developed a novel vaccine technology that combines synthetic biology, protein structure analysis, computational biology, and immune optimization. They claim that this approach increases the effectiveness of a vaccine and widens its spectrum of protection against past, current, and future virus outbreaks.
During their study, the researchers came across an antigen structure that can trigger immune responses against many SARS-Cov-2 and SARS viruses. Antigens are proteins found in pathogens against which our immune system produces antibodies.
The researchers combined the antigen with a DNA immunogen (genetic material that encodes antigen), a weak virus, and an mRNA vaccine to develop a new vaccine candidate. In the next step, they used computer simulations and structurally engineered antigens to pinpoint the sections in a virus necessary for replicating and completing its life cycle.
These sections were identified as the targets for their vaccine. Finally, they tested their vaccine candidate on mice, rabbits, and guinea pigs against various coronaviruses. Vaccination resulted in a strong immune response in all animal subjects.
“These optimized synthetic antigens generate broad immune responses, targeted to the key sites of the virus that can’t change easily. It opens the door for vaccines against viruses that we don’t yet know about. This is an exceptionally different vaccine technology – it’s a real turning point,” Heeney said.
The vaccine candidate is both successful and safe in animals. Scientists are currently conducting the first human trials of the antigen vaccine.
If successful, this will change how scientists have been dealing with viruses, and the world will possibly have the most effective SARS-Cov-2 vaccines.
Furthermore, this vaccine technology also has the potential to give rise to similar vaccines for viruses other than SARS-Cov-2.
The study is published in the journal Nature Biomedical Engineering.