Frequency and Predictors of Refusal of Seasonal Influenza Vaccination among Patients at a Large Tertiary Referral Hospital
Methods: We obtained electronic medical record data for all patients ≥ 18 years admitted during 5 influenza seasons (Oct. 1 to Mar. 31, 2008 to 2013). Only the first admission per season per patient was included. We described vaccination and refusal rates by season, and identified factors associated with refusing the vaccine using multivariable logistic regression.
Results: There were 52,141 first admissions assessed for vaccination status over 5 influenza seasons. Self-reported influenza vaccination prior to admission ranged from 39% in 2008–2009 to 48% in 2012–2013 (Figure 1).
Of the 29,113 unvaccinated patients, 3% (n=742) had contraindications. Of 28,371 vaccine-eligible patients, refusal rates ranged from 60% in 2009–2010 to 71% in 2012–2013 (Figure 1). Reasons for refusal included "believes not at risk" (50%; n=9,243), "wants further advice" (16%; n=2,950), and "fear of adverse events" (13%; n=2,416), and "other" (22%; n=4,102). Distributions of refusal reasons were similar for individual influenza seasons.
After controlling for influenza season, female sex, being currently employed, and English as a primary language were associated with higher odds of refusing vaccine. Current smoking and admission to an ICU were associated with lower odds of refusing vaccine.
Conclusion: Influenza vaccination rates prior to admission were similar to those of the general adult US population. During the past 5 influenza seasons, nearly two-thirds of vaccine-eligible inpatients refused the vaccine. A number of factors were found to be associated with refusal and may help develop focused interventions to decrease influenza vaccine refusal among inpatients.
Figure 1. Self-reported seasonal influenza vaccination prior to first hospital admission and refusal rates of seasonal influenza vaccine among eligible patients in a given influenza season.