Immunization coverage among infants enrolled in the Tennessee Medicaid program

Area of Science:

• Pediatric Health
• Public Health Policy
• Health Services Research

Background:

• Infant immunization is critical for preventing childhood diseases.
• Medicaid enrollees often face barriers to healthcare access, potentially impacting vaccination rates.
• Understanding coverage gaps is essential for improving public health outcomes.

Purpose of the Study:

• To assess immunization coverage among infants enrolled in Tennessee Medicaid.
• To identify risk factors associated with incomplete vaccinations by 24 months of age.

Main Methods:

• Retrospective cohort study of 33,615 infants enrolled in Medicaid in three Tennessee urban counties (1980-1989).
• Assessed receipt of diphtheria-tetanus-pertussis, oral polio, and measles-mumps-rubella vaccines by 24 months.
• Data sources included computerized county immunization records and Medicaid billing files.

Main Results:

• Overall, only 45% of infants completed recommended vaccinations by 24 months.
• Vaccination completion rates varied by county of birth (37%-63%) and decreased from 1982 (50%) to 1989 (44%).
• Key predictors of completion included fewer prior births for the mother, timely first immunization, and county of birth; maternal demographics showed weak associations.

Conclusions:

• Less than half of Tennessee Medicaid infants in the study completed recommended vaccinations by age two.
• Significant disparities in immunization levels between counties, unexplained by demographics, suggest systemic issues in healthcare delivery.
• Improving immunization coverage requires addressing health care and vaccine delivery system factors for this vulnerable population.