ABSTRACT
The word vaccine is usually restricted to describe an immunogen administered to healthy subjects at risk prior to their becoming exposed to a microbial pathogen. This word is also often used when the immunogen is administered early after exposure but before the onset of disease manifestations; in such circumstances the qualifying prefix “postexposure” is employed. Given the conventional use of the word vaccine, the term vaccine therapy might seem to be an oxymoron. However, historical precedent suggests that the term vaccine therapy should be used to describe administration of a microbe-specific antigen for therapeutic purposes (after the onset of established disease) [1]. Indeed, “vaccine therapy” and “vaccinotherapy” have been used continuously for this purpose as medical subject headings in the Index Medicus since 1911. While alternative terms have been proposed (immunoregulation, immunotherapy, immunostimulation), they are overly general and fail to convey the meaning that the immunity sought in vaccine therapy is both active and directed against microbe-specific antigens. Thus vaccine usage can be categorized relative to the time of microbial exposure: (1) true prevention or prophylaxis, (2) postexposure prophylaxis, and (3) therapy or reduction of recurrences.
