The major symptoms of chronic mercury poisoning in children, according to the Centers for Disease Control:
Tremors in extremities.
Impaired motor control, manifesting as difficulty walking.
Personality changes (described in the study as "characterized by irritability,
excessive shyness, confidence loss, and nervousness"...
This seems to refute vaccination.
No, it doesn't, as smallpox vaccination didn't exist until 1794.
What the graph does show is that the ancient practice of variolation usually worked. Variolation involved intentionally infecting oneself with the pus from a smallpox pustule taken from an infected person, usually resulted in variola minor, also known as ...
More research has been conducted on the topic since 2011, and the answer should now be revised from yes, to requires more evidence.
From The Skeptic's Guide to Sports Science: Confronting Myths of the Health and Fitness Industry by Nicholas B. Tiller (Routledge; April 15, 2020):
The most recent studies in this domain bring into question the