A dynamic, multi-level analysis of recent immunization trends in Colombia

Area of Science:

• Public Health
• Epidemiology
• Health Services Research

Background:

• The successful Regional Polio Eradication Initiative (1985-91) achieved high vaccine coverage through mass campaigns and improved routine services.
• The impact of these interventions on immunization demand and reach to high-risk households remains understudied.

Purpose of the Study:

• To examine the probability and timing of full immunization in Colombia during the Polio Eradication Initiative.
• To assess whether program effects offset household risk factors for immunization.

Main Methods:

• Analysis of 3,609 children's immunization status from Colombia's 1990 Demographic and Health Survey (born 1985-90).
• Appended annual immunization coverage data (1985-90) for 148 municipios and household-level data.
• Utilized non-parametric regressions and multivariate logit models to identify risk factors and program effects.

Main Results:

• Five of six observed risk factors negatively influenced full immunization probability.
• Parents who lost a child were less likely to obtain immunization cards, despite rising rates.
• High local program coverage (≥80%) and prior prenatal service use increased immunization probability.
• Maternal occupation and household factors also impacted immunization probability.

Conclusions:

• Immunization demand for routine services rose, with high-risk households being less exposed to the program.
• Routine program participation partially mitigated negative risk factor effects on immunization.
• Targeted primary health care (PHC) interventions can recruit high-risk households, but intensive follow-up is needed for further gains.