preventionist
/prɪˈvɛnʃ(ə)nɪst/ /prɪˈvɛnʃ(ə)nɪst/noun
A person who favours or advocates a policy of prevention. Also with modifying word designating the thing (to be) prevented.
Origin
Early 20th century; earliest use found in The Edwardsville Intelligencer. From prevention + -ist.