Only Vaccine That Existed Before the 19th Century
Puzzle 14 of Ghost Hunting Hard Pack
Question is: Only Vaccine That Existed Before the 19th Century
and the answer is: SMALLPOX
Word Meaning:
SMALLPOX — (pathology) An acute, highly infectious often fatal disease caused by Variola virus of the family Poxviridae. It was completely eradicated in the 1970s, but still exists in laboratories. Those who survived were left with pockmarks.
Definitions from Wiktionary.