Metal Nanoparticles against Viruses: Possibilities to Fight SARS-CoV-2
Not being first in line for those, either.
Chapter 5 - Role of metal nanoparticles for treatment of and prevention of viral infections
Scroll down, way, way down for this bit...
...Although MNPs do have advantages such as easy adaptation of custom modifications during synthesis, their nonbiodegradable nature always raises concerns over the possibility of chronic inflammation due to long-term accumulation in the system. Thus it may be the reason why there has not been any INP-based vaccine approved for clinical use yet.