A person who is not susceptible to infection by a particular disease

To make immune.

(usually with "from") Exempt; not subject to.

“As a diplomat, you are immune from prosecution.”

(usually with "to") Protected by inoculation, or due to innate resistance to pathogens.

“I am immune to chicken pox.”

(by extension) Not vulnerable.

“Alas, he was immune to my charms.”