Trends in Influenza Vaccination Rates among a Medicaid Population from 2016 to 2021.

Publication date: Nov 11, 2023

Seasonal influenza is a leading cause of death in the U. S., causing significant morbidity, mortality, and economic burden. Despite the proven efficacy of vaccinations, rates remain notably low, especially among Medicaid enrollees. Leveraging Medicaid claims data, this study characterizes influenza vaccination rates among Medicaid enrollees and aims to elucidate factors influencing vaccine uptake, providing insights that might also be applicable to other vaccine-preventable diseases, including COVID-19. This study used Medicaid claims data from nine U. S. states (2016-2021], encompassing three types of claims: fee-for-service, major Medicaid managed care plan, and combined. We included Medicaid enrollees who had an in-person healthcare encounter during an influenza season in this period, excluding those under 6 months of age, over 65 years, or having telehealth-only encounters. Vaccination was the primary outcome, with secondary outcomes involving in-person healthcare encounters. Chi-square tests, multivariable logistic regression, and Fisher’s exact test were utilized for statistical analysis. A total of 20,868,910 enrollees with at least one healthcare encounter in at least one influenza season were included in the study population between 2016 and 2021. Overall, 15% (N = 3,050,471) of enrollees received an influenza vaccine between 2016 and 2021. During peri-COVID periods, there was an increase in vaccination rates among enrollees compared to pre-COVID periods, from 14% to 16%. Children had the highest influenza vaccination rates among all age groups at 29%, whereas only 17% were of 5-17 years, and 10% were of the 18-64 years were vaccinated. We observed differences in the likelihood of receiving the influenza vaccine among enrollees based on their health conditions and medical encounters. In a study of Medicaid enrollees across nine states, 15% received an influenza vaccine from July 2016 to June 2021. Vaccination rates rose annually, peaking during peri-COVID seasons. The highest uptake was among children (6 months-4 years), and the lowest was in adults (18-64 years). Female gender, urban residency, and Medicaid-managed care affiliation positively influenced uptake. However, mental health and substance abuse disorders decreased the likelihood. This study, reliant on Medicaid claims data, underscores the need for outreach services.

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Concepts Keywords
Basel COVID-19
Healthcare influenza vaccine
Influenza Medicaid
June vaccination uptake
Lowest vaccine


Type Source Name
disease MESH Influenza
disease VO vaccination
disease VO population
disease VO Optaflu
disease MESH cause of death
disease MESH morbidity
disease VO vaccine
disease MESH vaccine-preventable diseases
disease MESH COVID-19
disease VO vaccinated
disease MESH substance abuse
disease VO USA
drug DRUGBANK Silver
disease MESH death
drug DRUGBANK Coenzyme M
disease VO effective
disease IDO intervention
disease MESH chronic diseases
disease MESH asthma
pathway KEGG Asthma
disease MESH heart disease
disease MESH pneumonia
disease VO pregnant women
disease VO licensed vaccine
disease MESH liver disease
disease MESH Diabetes Mellitus
disease MESH emergency
disease VO frequency
disease VO unvaccinated
disease VO time
disease MESH Diabetes mellitus complication
disease MESH labor complications
disease MESH high risk pregnancy
disease MESH complications
disease MESH infectious disease
pathway REACTOME Infectious disease
disease MESH neoplasm
disease MESH mental disorders
disease MESH Refractive error
disease MESH Cataract
disease MESH upper respiratory infections
disease MESH Heart failure
disease MESH Nervous System Disorder
disease MESH Epilepsy
disease MESH convulsions
disease MESH Neurodevelopmental Disorders
disease MESH Schizophrenia
disease MESH psychotic disorders
disease MESH Opioid related disorders
disease VO immunization
disease VO organization
disease VO influenza vaccines
disease MESH bipolar disorder
drug DRUGBANK Medrysone
disease MESH Allergy
disease VO report
disease VO vaccine effectiveness
disease VO effectiveness
disease IDO country
disease MESH rheumatic diseases
disease IDO blood
disease IDO quality
disease VO USDA
disease VO vaccination coverage

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