Immunization coverage and its relationship to preventive health care visits among inner-city children in Baltimore

Abstract

Objective: To provide empirical data on immunization coverage and the receipt of preventive health care to inform policy makers' efforts to improve childhood immunization.

Design and methods: We surveyed a random sample drawn from a birth cohort of 557 2-year-old children living in the inner-city of Baltimore. Complete information on all their preventive health care visits and immunization status was obtained from medical record audits of their health care providers.

Main outcome measures: Age-appropriate immunizations and preventive health care visits.

Results: By 3 months of age, nearly 80% made an age-appropriate preventive health visit, but by 7 months of age, less than 40% had a preventive visit that was age-appropriate. In the second year of life, 75% made a preventive health visit between their 12- and 17-month birthdays. The corresponding age-appropriate immunization levels were 71% for DTP1, 39% for DTP3, and 53% for measles-mumps-rubella vaccine. Infants who received their DTP1 on-time were twice as likely to be up-to-date by 24 months of age.

Conclusions: Our analyses focus attention on the performance of the primary health care system, especially during the first 6 months of life. Many young infants are underimmunized despite having age-appropriate preventive visits, health insurance coverage through Medicaid, and providers who receive free vaccine from public agencies. Measles vaccination coverage could be improved by initiating measles-mumps-rubella vaccine vaccination, routinely, at 12 months among high risk populations.