Risk factors for underimmunization in poor urban infants

Abstract

Objective: To assess risk factors for underimmunization in poor urban infants.

Design: Prospective cohort study.

Setting: A large municipal teaching hospital in the Midwest.

Participants: A total of 464 healthy, full-term newborn infants delivered at a large municipal teaching hospital who were to be discharged to the care of their mothers. Mothers were interviewed 24 to 72 hours post partum regarding personal and financial characteristics and 9 to 12 months later to determine where immunizations had been received.

Main outcome measures: Immunization status at 3 and 7 months of age.

Results: Despite availability of free vaccine to most patients, only 67% had received their first set of immunizations by 3 months of age, and only 29% were up-to-date by 7 months of age. Marital status, coresidence with the infant's grandmother, adequacy of prenatal care, and perceived barriers to care were significant independent predictors of initiation of immunizations by 3 months and completion of immunization by 7 months. Poverty was also an independent predictor of immunization status at 7 months. Perceived susceptibility to common symptoms and perceived benefit of medical care to prevent disease were inversely related to immunization status at 7 months.

Conclusions: These data suggest that poor urban infants of single mothers and of mothers who received inadequate prenatal care, and those not living with their grandmother should be targeted for tracking and follow-up to ensure adequate immunization. The provision of free vaccine alone will not guarantee adequate immunization coverage of poor urban children.