A new type of vaccine provides protection against a variety of SARS-like betacoronaviruses, including SARS-CoV-2 variants, in mice and monkeys, according to a study led by researchers in the laboratory of Caltech’s Pamela Bjorkman, PhD, the David Baltimore Professor of Biology and Bioengineering. The vaccine, known as a mosaic nanoparticle, presents the immune system with pieces of the spike proteins from SARS-CoV-2 and seven other SARS-like betacoronaviruses, attached to a protein nanoparticle structure, to induce the production of a broad spectrum of cross-reactive antibodies.