Early childhood vaccination coverage and patterns by rural-urban commuting area.

Introduction: National surveillance efforts have reported rural-urban disparities in childhood vaccination coverage by metropolitan statistical area designations, measured at the county level. This study's objective was to quantify vaccination trends using more discrete measures of coverage and rurality than prior work.

Methods: Serial, cross-sectional analyses of National Immunization Survey-Child restricted-use data collected in 2015-2021 for US children born 2014-2018 were conducted. ZIP code of residence was merged with rural-urban commuting area (RUCA) codes. Vaccination coverage and patterns, including on-time receipt of recommended vaccines, were assessed using vaccinations recorded from birth through age 23 months. To determine whether trends differed by rurality, an interaction between birth year and RUCA was tested in multivariable regression models. Analyses were conducted in November 2023-January 2024.

Results: In nationally-representative analyses of n=59,361 children, 87.7%, 7.1%, and 5.3% lived in urban, large rural, or small town/rural areas, respectively. Among children born in 2018, coverage for the combined 7-vaccine series was 71.2% (95% CI: 69.6%-72.9%) in urban, 64.9% (95% CI: 58.8%-71.0%) in large rural, and 62.6% (95% CI: 56.2%-68.9%) in small town/rural areas. There was a positive trend in on-time vaccination in urban areas (adjusted prevalence ratio [aPR] for birth year=1.06, 95% CI: 1.05-1.08). While the trend did not significantly differ for large rural versus urban areas (interaction aPR: 1.02, 95% CI: 0.96-1.08), there was less improvement in on-time vaccination in small town/rural areas (interaction aPR: 0.93, 95% CI: 0.88-0.99).

Conclusions: Increased efforts are needed to eliminate disparities in routine and on-time vaccination for rural children.