Khurana et al. outline the rapid search for a COVID-19 vaccine and the advantages of a nanoparticle-based vaccine carrier. Pfizer and Moderna were the first mRNA-based, lipid nanoparticle (LNP) vaccines approved for emergency use by the FDA. These vaccines showed high efficacy in clinical trials, and the authors highlight the role nanoparticles play in this successful outcome. mRNA vaccines are non-infectious, do not require penetration of the nucleus, and can be produced rapidly compared to vaccines based on inactivated or live viruses. LNP-based carrier molecules allow for preservation of mRNA and enhanced uptake by cells. LNPs typically consist of an ionizable lipid portion, a stabilizing agent, a phospholipid portion to stabilize the bilayer, and polyethylene glycol (PEG) which makes them rigid and kinetically stable. Their simple synthesis, size, stability, biocompatibility, and efficacy in delivery with their physiological charge neutrality makes them a strong development from liposome systems. However, they can further be improved by stabilizing thermal degradation and enhancing cell penetration, specifically in the case of negatively charged cell membranes. Although mRNA vaccines have shown side effects and allergic reactions due to PEG, they are a promising development of nanoscale delivery systems for future applications in medicine.