There IS a piece of work underway, supported by the Gates Foundation, to support vaccine tracking through the use of 'quantum dot technology' within the vaccine does.
This research is being undertaken by one of the foremost institutions in the States, MIT, and has the potential to be highly valuable in low-income, low tech settings.
It is worth being aware of when discussing with anti-vaxxers so that they do not surprise you with "evidence"
https://news.mit.edu/2019/storing-vaccine-history-skin-1218
Biting the hand that feeds IT
