The myth goes back hundreds of years to the unscientific hypothesis and work of Edward Anthony Jenner (1749-1823), who is credited as being the 'father of vaccines' and the 'father of immunology'. First and foremost, Jenner's been touted as being a physician, and that 'factoid' has been disputed over and over again.
It turns out Jenner's first smallpox vaccination experiment (his own son) ended up with brain damage and died young, most likely from a vaccine-related immune deficiency. The medical textbook definition of a vaccine adverse reaction is encephalitis (brain inflammation) which can lead to permanent neurological damage (aka brain damage, autism, developmental delay). [....]Since Jenner obviously was an 'astute' business person, he was able to convince others that his newfangled health hypothesis was a moneymaker.
By 1807, he [Jenner] convinced the Royal College of Physicians and the British Parliament that his once defunct and admittedly unprotective vaccine was safe and effective, and as well could produce large revenues. [CJF emphasis added]