Individual and community socioeconomic status and receipt of influenza vaccines among adult primary care patients in a large academic health system: 2017-2019.

Introduction: Influenza causes significant mortality and morbidity in the U.S., yet less than half of adults receive influenza vaccination. We use census-tract level social vulnerability index (SVI) to examine community- and individual-level characteristics of influenza vaccine coverage among primary care patients at an academic health system in Los Angeles, CA.

Methods: We used electronic medical records (EMR) data of 247,773 primary care patients for 2017-18 and 2018-19 influenza seasons. We geocoded patients' addresses to identify their SVI and merged them with EMR data. We specified mixed-effects logistic regression models estimating the association between patient's vaccine receipt and SVI, adjusting for sociodemographics, Charlson Comorbidity Index, and health insurance.

Results: Vaccination coverage was higher during the 2018-19 influenza season (34%) compared to the 2017-18 season (23%). In adjusted analyses, higher SVI, lower individual socioeconomic status and racial and ethnic minority status were independently associated with lower odds of vaccination. Patients on Medicaid had lower odds of vaccine receipt (adjusted Odds Ratio [aOR] = 0.77 for <65, aOR = 0.30 for 65+) than patients on commercial health insurance. Asian Non-Hispanic patients had higher odds than White Non-Hispanic patients (aOR = 2.39 for <65, aOR = 1.91 for 65+), while Black Non-Hispanic patients had lower odds (aOR = 0.49 for <65, aOR = 0.59 for 65+).

Conclusions: Community and individual socioeconomic status and race and ethnicity were associated with influenza vaccination. Health systems can use SVI to identify communities at increased risk of influenza mortality and morbidity, and engage with community partners to develop communication strategies and invest in interventions to increase vaccine accessibility in under-resourced neighborhoods.