--G. Carlin
Doctors 'flabbergasted' that half of parents think flu shot causes the flu
https://www.aol.com/article/news/2018/10/17/doctors-flabbergasted-that-half-of-parents-think-flu-shot-causes-the-flu-its-impossible/23563742/
This seems extremely high, but it isn't entirely surprising. We've always had half the population with below average intelligence, but now they are drowning out the reasonable people by shouting loud at each other and they can't figure out what is true anymore.
In their defense, the relatively low effectiveness of the flu vaccine -usually less than 50%, often in the teens- has clouded the issue.