post-exposure prophylaxis noun1 •A form of prevention, usually medication, taken after exposure (or probable exposure) to a pathogen, preventing development of disease after such exposure; especially, as against HIV.Rape victims should be informed of the option of post-exposure prophylaxis to prevent HIV, in addition to emergency contraception.Post-exposure prophylaxis may be discontinued if the animal involved is a dog or cat that remains healthy..., WHO expert consultation on rabies: first report formspost-exposure prophylaxes