I believe research like that shown below (2009) points to the use of nano particles to trigger an immune response as if the particles were 'living' pathogens, and this was likely used to create the appearance of a Plandemic, and to keep it going with 'vaccine' campaigns. It helps explain why the 'filthy elites' are not afraid of contagion and party/socialize without masks etc.
https://www.pnas.org/content/106/14/5497
Quoting from the article:
"Vaccines are among the most specific, effective, and efficient tools developed to prevent a multitude of illnesses. Despite their many successes, vaccines often suffer from either inadequate immunogenicity or safety. An ideal vaccine would be highly stimulatory, yet completely safe, and would allow for the prevention or treatment of diseases that are otherwise difficult to treat. Particle-based immunotherapy holds great promise for the development of such a system because particles can mimic active pathogens but are not infectious (1). "
