This is a statement that cannot be substantiated with any confidence. In particular, the Native American side of the Columbian exchange saw massive body counts due to a mixture of diseases and my understanding is that chicken pox is among the suspects.

It isn't "quackery" just because you don't like it.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957993/

(edit: 'javagram got there first!)