| Date | 7th, Jul 2022 |
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As scientists frantically chase a rapidly mutating SARS-CoV-2 virus by trying to update current COVID vaccines to better target circulating variants, a huge project is bubbling away in the background. The goal is to create a universal coronavirus vaccine designed to generate such broad immunity it will protect people from all currently circulating strains of SARS-CoV-2, as well as any future variants yet to emerge. And there are several compelling candidates in the pipeline.
A new study published in the journal Science is reporting promising results from preclinical studies led by researchers at Caltech. The vaccine utilizes a novel mosaic nanoparticle technology to protect not only against SARS-CoV-2 but also the original SARS, and several common cold coronaviruses.
The experimental vaccine focuses on a particular genera of coronaviruses called betacoronaviruses. These are the most clinically relevant types of coronaviruses to humans, including SARS, MERS, SARS-CoV-2, and two coronaviruses linked to the common cold - OC43 and HKU1.
Pamela Bjorkman, a Caltech researcher leading the project, said generating broad immunity against the entire group of betacoronviruses should offer protection from new viruses that could emerge in the future. And considering we’ve had three dangerous viruses emerge from the betacoronavirus family over the past 20 years, it is crucial to get ahead of what could be the next pandemic.
“What we're trying to do is make an all-in-one vaccine protective against SARS-like betacoronaviruses regardless of which animal viruses might evolve to allow human infection and spread,” said Bjorkman. “This sort of vaccine would also protect against current and future SARS-CoV-2 variants without the need for updating."
The Caltech vaccine uses nanoparticle scaffolds to attach a number of different betacoronavirus fragments. Eight different betacoronaviruses are targeted by the vaccine: SARS-CoV-2, and seven other betacoronaviruses currently only circulating in animals but all holding the potential for mutating into a form that could infect humans in the future.
The vaccine does not focus on the traditional coronavirus spike protein, but instead uses viral fragments called receptor-binding domains (RBDs). These are parts of the virus that act as a kind of interface between the spike protein and ACE2 receptors in human cells. RBDs are like the anchor that links the virus up with the human receptor.
