Authors: Nina B. Masters, PhD, MPH ⊕Truveta, Inc, Bellevue, WA, Brianna M. Goodwin Cartwright, MS ⊕Truveta, Inc, Bellevue, WA, Patricia J. Rodriguez, PhD, MPH ⊕Truveta, Inc, Bellevue, WA, Karen G. Farrar, PhD ⊕Truveta, Inc, Bellevue, WA, Duy Do, PhD ⊕Truveta, Inc, Bellevue, WA, Nicholas L. Stucky, MD, PhD ⊕Truveta, Inc, Bellevue, WA
A total of 2,065 measles cases have been reported in the US as of December 30, 2025, reaching their highest levels since elimination in 2000. MMR (measles, mumps, and rubella) vaccination coverage has decreased, and factors associated with delayed and missed vaccination since the COVID-19 pandemic are not well explored.
Truveta Research sought to characterize coverage and trends of timely MMR vaccination and assess factors associated with late vaccination and nonvaccination by 2 years of age.
Methods
In this cohort study, infants who accessed routine care within the first 2 months, first year, and second year of life were followed for 24 months to assess vaccination outcomes between January 1, 2018 and April 30, 2025. Participants were children seeking care within Truveta member health systems and included in Truveta Data.
The primary outcome was timely, late, or no receipt of MMR by 2 years of age. Associations with primary exposures and sociodemographic factors were modeled using mized-effect logistic regression with state-level random effects. Models were stratified by pre- vs. post-COVID-19 MMR eligibility, with results after the COVID-19 pandemic reported as primary.
Results
In this study of 321,743 children (166,017 boys [51.6%]) with regular access to care, 78.4% (252,250 of 321,743) received their first MMR vaccination on time, increasing from 75.6% (12,840 of 16,978) in 2018 to 79.9% (39,739 of 49,767) in 2021, then decreasing to 76.9% (40,306 of 52,388) in 2024. The strongest factors associated with no MMR vaccination by 2 years was late administration of a child’s 2-month vaccines (adjusted odds ratio [AOR], 6.96 [95% CI, 6.60-7.34]) and 4-month vaccines (AOR, 6.16 [95% CI, 5.84-6.50]).
Discussion
In this cohort study of children with regular access to care, most received their MMR vaccine on time, but the proportion not receiving the MMR vaccine by 2 years of age has increased since the COVID-19 pandemic. Children who did not receive their 2- and 4-month vaccines on time were significantly more likely to not receive any MMR vaccine by 2 years, highlighting opportunities for intervention.
You can read the full study in JAMA Network Open.
You can also explore the full study directly in Truveta Studio.