Stevemcau the meaning of the "pure blood" reference isn't obvious at all. So, mRNA vaccine bad, non-mRNA covid-19 vaccine okay?
Swabbing "pure bloods" would likely find a range of substances, eg alcohol, cannabis etc, rendering the term little more than wishful thinking - like so much of antivaxx guff.
moreover, the antivaxx cult has chosen to appropriate a term that also had links to German SS membership requirements. Does this happen by chance? I doubt it.