Do you remember the swine flu from 2009?
A couple of years ago (in the year after the swine flu craze), I was at the doctor's to get my yearly seasonal flu shot when I read the label on the vaccine vial stating that it was a seasonal flu / swine flu compound mix. Apparently the manufacturer got rid of their leftovers from the previous year by the help of a cost efficient second cycle use. I doubt that many people, who got their seasonal flu shot that year, were told what else they were injected with.
I politely declined.