http://www-bsac.eecs.berkeley.edu/publications/search/send_publication_pdf2client.php?pubID=1386131736
https://en.wikipedia.org/wiki/Magnetorheological_fluid
https://en.wikipedia.org/wiki/List_of_emerging_technologies
The direct connection to the vaccines is still inconclusive, but it could explain the magnetism on the vaccine sites.
Berkeley paper above explains the technology for magnetically encapsulated medicines.