pre-exposure
adjective
pre-ex·po·sure ˌprē-ik-ˈspō-zhər 
variants or less commonly preexposure
: occurring, administered, used, or being in the period preceding exposure (as to a stimulus or a pathogen)
pre-exposure rabies vaccination
Canon has also added a red-eye reduction pre-exposure light …
Herbert Keppler
see also pre-exposure prophylaxis Herbert Keppler pre-exposure noun
Rats differ from monkeys and chicks in that simultaneous pre-exposure to two stimuli does facilitate their subsequent discrimination … R. A. Hinde
R. A. Hinde 
Word History
First Known Use
1906, in the meaning defined above
Medical Definition
pre-exposure
adjective
pre-ex·po·sure -ik-ˈspō-zhər
variants preexposure
: of, relating to, occurring in, or being the period preceding exposure (as to a stimulus or a pathogen)
pre-exposure immunization