77 - Association between County-Level Adult COVID-19 Vaccination and Pediatric Vaccination Rates in Michigan
Friday, April 28, 2023
5:15 PM – 7:15 PM ET
Poster Number: 77 Publication Number: 77.149
Caroline M. Hogan, University of Michigan Medical School, Ann Arbor, MI, United States; Aaron S. Parzuchowski, University of Michigan Medical School, Ann Arbor, MI, United States; James Henderson, University of Michigan Medical School, Ann Arbor, MI, United States; Pooja Patel, University of Michigan, Ann Arbor, MI, United States; Kevin Dombkowski, University of Michigan Medical School, Ann Arbor, MI, United States
Research Fellow University of Michigan Medical School Ann Arbor, Michigan, United States
Background: A prior study found that states with the lowest adult COVID-19 vaccination rates in 2021-2022 experienced the greatest decline in adult influenza vaccinations. It is unknown whether adult COVID-19 vaccination rates – a possible proxy for broader vaccination attitudes – are associated with area-level changes in non-COVID-19 pediatric vaccination rates. Objective: To evaluate whether county-level adult COVID-19 vaccination rates are associated with changes in county-level pediatric vaccination rates in Michigan. Design/Methods: We analyzed publicly-available, county-level, quarterly vaccination data from the Michigan Care Improvement Registry, a lifespan state immunization registry. The study period included Q4 2013-Q4 2019 (pre-pandemic) and Q3 2021-Q2 2022 (when adult COVID-19 vaccines were broadly available). The independent variable was the COVID-19 primary vaccine series completion rate in Q4 2021 among adults 20-49 years, the age range of many parents of young children. The dependent variable was the quarterly 4313314 composite vaccine series completion rate for 19-35-month-olds, which includes ≥ 4 DTaP, ≥ 3 polio, ≥ 1 MMR, ≥ 3 hepatitis B, ≥ 1 varicella, ≥ 4 PCV, and ≥ 3 Hib vaccine doses. Using an interrupted time series design, we evaluated for differential level and slope changes per 10% increase in adult COVID-19 vaccination rates in Q4 2021. We used a population-weighted, negative binomial mixed model with fixed effects for the intercept, slope, level change, and slope change and county-level random effects for all terms. Results: The unadjusted mean quarterly rates of completion of the 4313314 composite vaccine series were 74.7% pre-pandemic and 69.1% during the period of broad adult COVID-19 vaccine availability (difference: -5.6%). Higher adult COVID-19 vaccination rates were associated with higher pre-pandemic levels of pediatric vaccination (relative risk per 10% increase: 1.003, 95% CI: 1.001-1.026) and smaller intra-pandemic declines in pediatric vaccination (relative risk per 10% increase: 1.013, 95% CI: 1.001-1.026). Put differently, each 10% increase in adult COVID-19 vaccination rate was associated with a 1.3% (95% CI: 0.1-2.6%) reduced decline in the quarterly pediatric vaccination rate, but no slope change (relative risk per 10% increase: 0.985, 95% CI: 0.969-1.001).
Conclusion(s): Higher county-level adult COVID-19 vaccination rates were associated with a smaller level of decline in pediatric vaccination rates during the COVID-19 pandemic. Future research should evaluate whether a similar association exists between pediatric COVID-19 and other pediatric vaccination rates.
