Routine childhood and adolescent immunizations declined in Michigan between 2017 and 2023, particularly among counties with lower household income and higher uninsurance rates, a new study suggests.
For many key pediatric vaccines, completion rates dropped sharply during the COVID-19 pandemic and have not yet recovered, according to Michigan Medicine-led findings in Pediatrics.
“Our findings show that progress toward increasing childhood and adolescent immunizations is stalling in Michigan, increasing the risk of vaccine-preventable diseases,” said senior author Kao-Ping Chua, M.D., Ph.D., a pediatrician and researcher at University of Michigan Health C.S. mott Children’s Hospital and the director of the Susan B. meister Child Health Evaluation and Research (CHEAR) center.
Researchers analyzed county-level data from Michigan’s immunization registry between 2017 and 2023. During the study period, completion rates of a recommended group of childhood immunizations among toddlers (including vaccines for pertussis, polio, and measles-mumps-rubella among others) fell from nearly 76% to 67%.
Meanwhile, completion rates of a recommended group of vaccinations among adolescents (including vaccines for meningitis, pertussis, and tetanus) declined from about 81% to 75%.
The study also assessed adolescent completion rates of the human papillomavirus (HPV) vaccination series-which can prevent several types of cancers, including cervical and throat cancer. Although completion rates rose modestly-from 35% to 42% for males and 43% to 45% for females-the increases were smaller.
Michigan Childhood Immunization Rates Vary by County
Childhood immunization rates in Michigan changed between 2017 and 2023, and these changes differed depending on the characteristics of each county. A recent study published in Pediatrics looked at these trends.
Researchers found that counties with more poverty, fewer primary care doctors, and a larger percentage of residents without health insurance tended to have lower immunization rates. Specifically, rates were lower for the combined series of diphtheria, tetanus, and pertussis (DTaP), measles, mumps, and rubella (MMR), and polio vaccines.
The study highlights the importance of addressing social and economic factors that can impact access to healthcare. These factors can create barriers to vaccination, leaving children vulnerable to preventable diseases.
Understanding these local differences is crucial for public health officials. Targeted interventions can be developed to improve immunization rates in the counties that need them most. This could include increasing access to affordable healthcare,providing transportation assistance to vaccination appointments,and conducting outreach to educate parents about the importance of vaccines.
More information: Changes in Childhood Immunization Rates by County Characteristics in Michigan: 2017-2023, pediatrics (2025). DOI: 10.1542/peds.2025-070781