Summary
The document discusses the change in the definition of the word “vaccine” by Merriam-Webster. The updated definition now includes not only traditional vaccines, which introduce a weakened or killed pathogen to stimulate immunity, but also new mRNA-based COVID-19 vaccines that work by instructing cells to produce a protein triggering an immune response. This redefinition reflects advancements in vaccine technology and acknowledges the broader range of methods used to confer immunity in light of the COVID-19 pandemic.