Social Determinants of Childhood Vaccination Coverage in the United States Using National Immunization Survey Data...

Vaccination in early childhood is essential to prevent serious infectious diseases and protect community health. In the United States, 7 vaccines (diphtheria, tetanus, and acellular pertussis; polio; measles, mumps, and rubella; Haemophilus influenzae type b; hepatitis B; varicella; and pneumococcal conjugate) are recommended by the Centers for Disease Control and Prevention for children aged 19-35 months, along with 3 others (hepatitis A, influenza, and rotavirus), which are recommended for full protection. Despite these guidelines, recent measles outbreaks in the United States have drawn attention to persistent gaps in coverage.

This cross-sectional study explores immunization patterns among children aged 19-35 months using provider-verified data from the National Immunization Survey-Child between 2010 and 2023.

Survey-weighted logistic regression models were used to assess associations between vaccination status and social determinants of health, including child age group, maternal education, insurance status, birth order, and region. Separate survey-weighted logistic regression models were fit for each survey year from 2010 to 2023. We considered the complex survey design to calculate vaccination coverage rates and their CIs, accounting for clustering and stratification in the sampling methodology. A composite variable was created to measure full coverage of the 7 recommended vaccines, and within each year, models were estimated separately for each individual vaccine and for the 7-vaccine series composite outcome to identify vaccine-specific barriers to immunization.

Provider-verified response rates declined from 70.8% (17004/24013) in 2010 to 47.7% (18412/38619) in 2023, although the analytic sample size remained stable. Coverage for the Combined 7-Vaccine Series increased from 70.8% (11893/16798) in 2010 to 77.4% (13957/18032) in 2023. Older age was consistently associated with higher odds of complete vaccination (2010: odds ratio [OR] 1.10, 95% CI 1.02-1.19; 2023: OR 1.24, 95% CI 1.13-1.35), whereas lack of insurance and Hispanic origin were associated with lower uptake for selected vaccines. In 2022, uninsured children had 26% lower odds of complete vaccination compared with insured children (OR 0.74, 95% CI 0.65-0.84). Higher income-to-poverty ratio was consistently associated with increased vaccination uptake, including influenza vaccination in 2020 (OR 1.25, 95% CI 1.13-1.39). Regional and language-related disparities persisted across survey years.

Persistent socioeconomic and structural gradients in childhood vaccination coverage highlight the need for equity-focused immunization strategies that address insurance access, language barriers, and geographic disparities.