A DYNAMIC, MULTILEVEL ANALYSIS OF RECENT IMMUNIZATION TRENDS IN COLOMBIA

During 1985-91, Latin American ministries of health carried out the ul timately successful Regional Polio Eradication Initiative. Unprecedent ed vaccine coverage levels were attained through a combination of mass campaigns, house-to-house vaccinations, and improvements in routine i mmunization services. Little is known, however, about the effects of t hese interventions on immunization demand; whether they reached so-cal led high-risk households and, if so, whether program effects were suff icient to offset the household risk factors. This paper examines the p robability and timing of full immunization over this period in one cas e country, Colombia. Information on the immunization status of 3,609 v accine-eligible children born 1985-90 was extracted from Colombia's 19 90 Demographic and Health Survey. Annual immunization coverage estimat es from the Colombian Ministry of Health for 1985-90 for 148 sample mu nicipios were appended to each child record, along with household-leve l data. Initial nonparametric regressions showed that five of six obse rved risk factors negatively influenced full immunization probability. Multivariate legit models showed that parents who had already lost a child were significantly less likely to obtain immunization cards (a p roxy for exposure to the routine immunization program), despite rising cardholdership rates over the period. Among 1,376 immunization cardho lders, waiting times to full immunization fell monotonically over the period. Local program coverage of 80 per cent or higher and prior use of prenatal services both increased the probability of full immunizati on. However, three of five maternal occupational categories decreased the probability, as did three of six observed household risk factors. The results show that demand for routine immunizations rose over the p eriod, that only the highest-risk households were not exposed to the r outine program, and that routine program participation partially offse t negative risk factor effects on the probability of full immunization . While targeted PHC interventions may increase health production by r ecruiting high-risk households into the routine PHC services, further health production increases will require more intensive follow-up of s uch households through routine PHC services.