Impressive increases in immunization rates have been reported in several less developed countries (LDCs) as a result of intensive EPI programs. An issue arises as to whether existing rates of immunization coverage can be sustained/increased given projected cutbacks in funding. This issue calls into question the assumption that as immunizable disease rates fall, local populations will need less encouragement to secure immunization services. This article considers how immunizations are perceived by lay populations and how perceptions of utility and need effect demand which in turn effects the sustainability of EPI programs. Among issues addressed is the observation that when specific diseases are not linked to specific immunizations, misimpressions related to the number of immunizations needed for "good health" abound. Also considered are metamedical reasons immunizations (and immunization programs) are both resisted and demanded in particular political contexts.