Perhaps you missed the part referring to Covid detection.
This is not about the vaccine.
In looking at the article as a whole...the article mostly talks about NP metal and magnetic for diagnosing
However...
In the abstract:
Strategies need to be explored to expand testing capacities, to develop effective therapeutics, and to develop safe vaccines that provide lasting immunity. Nanoparticles (NPs) have been widely used in many medical applications, such as biosensing, drug delivery, imaging, and antimicrobial treatment.
also note:
Nanoparticles for Therapeutics (Sec. 3)
Nanoparticles as Immunogenic Agents for Vaccines (Sec. 4)
4.2. Chitosan, Protein Cage, and Polymer Nanoparticles for Targeted Vaccine Delivery
NPs have been widely explored for drug delivery applications due to their favorable size, photothermal and magnetic properties...
the article also cites source articles about Magnetic NP.
For instance: “Magnetic nanoparticles for drug delivery”
The article talks about what can be done with NPs, but isn’t clear about what is being done with them in COVID cases.
.
And back to the original article...the discussion was about magnetic impurities in vaccines and why they shouldn’t be there....which took the author down a rabbit hole. (we do know about those)
Do NPs magnetize one’s body? I don’t know, I’ve been stuck on this refrigerator for 3 days...