The cold chain and the expanded program on immunization in Chile: an evaluation exercise.

It was decided that a study of the cold chain should be conducted in Chile in an effort to identify situations that could be corrected and to improve the technical and administrative development of the program. Specifically, study objectives were as follows: to determine the degree to which the EPI standards for procurement, receipt, transfer, control, maintenance, and distribution of vaccines were being met; to assess the turnover, knowledge, and training of auxiliary vaccination personnel against the relevant standards established for vaccine and cold chain management; to determine the antigenic potency of measles vaccine samples available at the time visits were made to local clinics, regional health storage sites, and the central supply facility; and to test a written instrument designed for the express purpose of assessing achievement of the first 2 objectives cited. The study sought to provide a descriptive assessment of work being performed at the central, regional, and local levels in the Metropolitan Region. The operating units involved included the airport and main supply center at the central level; the 7 storage facilities of the Metropolitan Region's 78 local clinics providing maternal and child health care. 40 clinics, selected by lot, represented 51% of the region's 78 clinics and provided coverage for 49% of the population assigned to the region's health services. The units studied failed to satisfy half the investigated Expanded Program for Immunization (EPI) standards, i.e., the average achievement rating of the 3 levels combined (49.3%) fell short of half the desired 100%. The airport unit met very few of the EPI implementation standards, scoring only 20% in this area. Deficiencies were found in systems for shipping vaccine in cold boxes, for making cold rooms permanently available, and for providing adequate vaccine transportation. The central supply facility, responsible for the purchase, storage, distribution, and maintenance of an adequate vaccine stock, had an achievement score of only 41%. The regional level, represented by the 7 storage facilities studied, obtained a lower overall achievement score than the other 2 levels and appears to be a high-risk link in the cold chain. The local level, represented by the 40 clinics studied, attained the highest average achievement score of any level (57%). Yet, serious deficiencies also emerged at this level, particularly regarding implementation and control activities. These deficiencies were aggravated by the fact that vaccines undoubtedly encounter a larger number of potentially damaging contingencies at the local level than they do elsewhere. Suggestions are made for overcoming these difficulties.