Several groups and consortia have been screening and characterizing nanomaterials according to their immunomodulatory properties and absence of cytotoxicity.56,57,82−84,86 The development of an adjuvant for clinical use is a lengthy process that requires extensive Phase III randomized trials in large and diverse cohorts of subjects, and the process generally requires several years.76 Pharmaceutical giants such as GlaxoSmithKline (GSK), which owns the ASs mentioned above and other adjuvant platforms, are engaged in several partnerships to embed their adjuvant systems with SARS-CoV-2-protein-based vaccines. A full-length recombinant SARS-CoV-2 glycoprotein nanoparticle vaccine adjuvanted with the saponin-based Matrix M developed by Novavax is in Phase I clinical testing (NCT04368988).89