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The Study on Mosaic-8 Vaccine
Context:
Researchers at the California Institute of Technology (Caltech) have been developing a vaccine candidate called mosaic-8.
More on News:
- This vaccine shows promise in protecting against multiple sarbecoviruses, including SARS-CoV-2 and its variants.
- A major challenge in developing effective vaccines for viruses like SARS-CoV-2 is the phenomenon known as “original antigenic sin” (OAS).
- OAS refers to the immune system’s tendency to preferentially respond to the first strain of a virus it encounters, potentially affecting responses to new strains or variants.
Background
Key Highlights:
- The study aimed to investigate whether OAS would impact the efficacy of a new broad-spectrum vaccine designed to protect against multiple sarbecoviruses.
- The study showed that mosaic-8 effectively stimulates cross-reactive antibodies in both animals previously exposed to SARS-CoV-2 and in those with no prior exposure.
- It was able to induce these antibodies in animals previously vaccinated with mRNA vaccines (like Pfizer and Moderna) as well as AstraZeneca’s ChAdOx1.
How does mosaic-8 work?
- It contains pieces from eight different sarbecoviruses, specifically receptor-binding domains (RBDs) of their spike proteins.
- These RBDs are crucial for the virus’s ability to infect cells and contain conserved regions that are similar across different sarbecoviruses.
- By targeting these conserved regions, mosaic-8 aims to elicit antibodies that provide protection against a range of sarbecoviruses and SARS-CoV-2 variants.
Implications:
- The ability of mosaic-8 to overcome the limitations posed by OAS and produce broadly protective antibodies is a promising development for future vaccine strategies.
- Phase 1 clinical trials for the mosaic-8 vaccine in humans are scheduled to begin in 2025.
- These trials will further evaluate the vaccine’s safety and efficacy in inducing cross-reactive antibody responses.