Illustration showing a nanoparticle (blue) formed from the protein ferritin coated with the spike proteins of different mutants of the SARS-CoV-2 virus. When the nanoparticle is injected into the body the proteins elicit a response from the immune system that will protect against any future infection. Ferritin nanoparticles are being researched as a platform to deliver vaccines against many different coronaviruses.