Researchers at the California Institute of Technology, better known as Caltech, have developed a nanoparticle vaccine that appears to confer broad protection against SARS-like betacoronaviruses. This includes SARS-CoV-2, responsible for the current pandemic, and SARS-CoV, which caused the original SARS pandemic in the early 2000s.
The vaccine consists of protein nanoparticles that are studded with spike protein elements of eight different SARS-like betacoronaviruses, including SARS-CoV-2, but the researchers hope that it will confer broad immunity to new viral strains, including new and existing variants of SARS-CoV-2 and other SARS-like betacoronaviruses that have yet to emerge. Such vaccine technologies may be the long-term answer to the ongoing COVID-19 pandemic, which is characterized by a seemingly never-ending progression of increasingly transmissible variants.
The COVID-19 pandemic may have fallen from the headlines, but SARS-CoV-2 continues to make people ill every day. Despite impressive vaccine development and an effective vaccination campaign, the incredibly high transmissibility and immuno-evasive cunning of the Omicron variant means that the virus is still disrupting our lives. Frustratingly, there is a possibility that a nightmare viral variant may emerge that combines the high transmissibility of Omicron with the potential to cause severe disease in more people.
We need to develop long-term strategies that help us protect ourselves ahead of time. Part of the issue is that our vaccines were developed against the original strain of SARS-CoV-2 that first emerged in China, and they are specifically targeted against the spike protein of that strain. However, SARS-CoV-2 is a member of the SARS-like betacoronaviruses, a group of viruses that include examples that made the leap from animal to human with deadly consequences, including the virus behind the MERS outbreak and the virus behind the original SARS pandemic in the early 2000s (SARS-CoV).
The researchers behind this latest vaccine technology took a scattergun approach, and designed a vaccine that combines elements of eight different SARS-like betacoronaviruses, including SARS-CoV-2. The protein nanoparticle is studded with receptor-binding domains from each of the viruses. The idea is to confer broad immunity against various types of betacoronaviruses, in the hope that this will be useful against future betacoronaviruses that pose a threat to humans, including new COVID-19 variants.
So far, the approach seems to be working. In tests in mice, the researchers found that the vaccine provided protection not only against viruses that were included in its design, but also against SARS-CoV, which was not. The results suggest that the vaccine could confer immunity against a broad selection of SARS-like betacoronaviruses, meaning it could be a superweapon in our ongoing fight against COVID-19 and beyond.
Study in journal Science: Mosaic RBD nanoparticles protect against challenge by diverse sarbecoviruses in animal models