I live in the U.S. and unfortunately, some people here have made the use of vaccines controversial. I have a Masters degree in Public Health and fully support the use of vaccines.
I think you should allow way more spelling errors. i.e. obstetrician of obstetrics, or just obstet. Narc for Narcolepsy. Lepr for Leprocy. I could not spell Hemophilia. I tried Hemophelia.
"Quack" isn't a slang term for a doctor (the way you have it worded implies that it can be used interchangeably). It's a term used to describe someone who doesn't know what they're doing or promotes junk science. You could say slang word for a bad doctor maybe...