Perinatal & Pediatric
Trends in on-time vaccination by rural-urban commuting area, National Immunization Survey-Child, 2015-2021 Sophia R. Newcomer* Sophia Newcomer Sarah Y. Michels Alexandria N. Albers Rain E. Freeman Christina L. Clarke Jason M. Glanz Matthew F. Daley
Background: The US Advisory Committee on Immunization Practices (ACIP) recommends multiple vaccine series, most involving several doses, from ages 0-19 months. Most surveillance efforts track completion of series by the 2nd birthday. However, vaccination timeliness is a more sensitive measure of disease protection and quality of immunization services received. Our objective was to quantify trends in on-time vaccination among US children by rural-urban commuting area (RUCA), a measure of urbanicity and rurality.
Methods: We analyzed data from CDC’s 2015-2021 National Immunization Survey-Child for children born 2014-2018. Zip code of residence, which is a restricted variable, was merged with RUCA categories from the USDA’s Economic Research Service. Our outcome was on-time receipt of the combined 7-vaccine series, determined by comparing the ages when children received vaccine doses to ACIP-recommended ages. We tested an interaction between birth year and RUCA in a log-linked binomial regression model adjusted for socioeconomic, demographic, and household factors. Analyses accounted for the complex survey design.
Results: Among n=59,361 children, 87.7%, 7.1%, and 5.3% lived in metropolitan, micropolitan, or small town/rural RUCAs. Overall, on-time vaccination increased from 28.4% (95% CI: 26.9-29.9%) among children born in 2014 to 36.4% (95% CI: 34.9-38.0%) in 2018. There were differences in this unadjusted trend by RUCA (Figure 1). In the multivariable model, there was a 6.2% average annual increase (95% CI: 4.5-8.0%) in on-time vaccination for children in metropolitan areas. While the trend did not differ for micropolitan versus metropolitan areas (interaction adjusted prevalence ratio [aPR]: 1.02, 95% CI: 0.96-1.08), the rate of improvement was less in small town/rural versus metropolitan areas (interaction aPR: 0.93, 95% CI: 0.87-0.99).
Conclusions: On-time vaccination in early childhood has improved nationally, though rural-urban disparities have widened.
