Director, Lead Epidemiologist, Infectious Diseases – Respiratory Vaccines Moderna, Inc., United States
Background: Vaccination is an essential strategy for preventing infectious diseases and controlling outbreaks, particularly for vulnerable populations such as older adults. However, the emergence of the novel SARS-CoV-2 pathogen and subsequent authorization of vaccines for COVID-19 elicited markedly variable attitudes and behaviors toward these vaccines and routine vaccination in general.
Objectives: To characterize the factors associated with intent to receive and receipt of both COVID-19 and influenza vaccination in older US adults (aged ≥50 years) between March 2020 and May 2021.
Methods: The eligible study population included those who responded to the COVID-19 module in the core survey of the national 2020 Health and Retirement Study (HRS), a longitudinal study on aging that surveys a representative sample of adults aged ≥50 years in the United States. Participant responses were categorized into 4 subgroups based on recent ( <2 years) influenza vaccination status (yes/no) and receipt of or intent to receive COVID-19 vaccination (yes/no). Bivariate and multivariable logistic regression was used to evaluate the association between the likelihood of receiving both COVID-19 and influenza vaccines (vs either or neither vaccine) and demographic, physical, and health-related characteristics of participants. Adjusted odds ratio (aOR) and 95% CI were calculated to describe the magnitude of the association. Survey weights were applied to all analyses.
Results: This analysis included 29450786 weighted population respondents. Based on bivariate analyses, covariates that were significantly associated with receiving both COVID-19 and influenza vaccines included age, race, education, concern for COVID-19, and certain comorbidities. According to the multivariable logistic regression analysis, significantly associated variates include having no degree vs 4-year college education (aOR, 0.52 [0.36-0.73]), being very concerned about COVID-19 vs little concern (aOR, 3.59 [2.54-5.06]), having previously received pneumococcal vaccination (aOR, 3.56 [2.81-4.52]), having had a cholesterol test in the past 2 years (aOR, 1.75 [1.34-2.30]), ever having arthritis (aOR, 1.31 [1.04-1.65]), ever drinking alcohol (aOR, 1.45 [1.08-1.96]), or having had preventative service in the past 2 years (aOR, 3.23 [2.69-2.66]). Additionally, being black was inversely associated with the increased likelihood of receiving both vaccines (aOR, 0.40 [0.31-0.52]).
Conclusions: Certain demographic and health-related characteristics are associated with an increased likelihood of receiving both COVID-19 and influenza vaccines in US older adults. Identifying these factors can provide important insight for understanding population behaviors regarding vaccination.
