Workplace availability, risk group and perceived barriers predictive of 2016-17 influenza vaccine uptake in the United States: A cross-sectional study.

BACKGROUND

Seasonal influenza, though mostly self-limited in the healthy adult, may lead to severe disease and/or complications in subpopulations. Annual influenza vaccination is available in many countries with coverage goals rarely being met. We conducted a cross-sectional study of influenza vaccine uptake and explored socio-demographic, economic, and psychological factors that explained vaccine uptake.

METHODS

The survey was administered via Amazon Mechanical Turk (MTurk) to United States residents in January 2017, using the Qualtrics platform. Using principal axis factor analysis, we reduced the 25 items theory-based psychological determinants into the primary constructs they measure if/when internal consistency was sufficient (Cronbach's alpha >0.60). Logistic regression models were used to quantify the association of socio-demographic, economic, and psychological factors with reported vaccine behavior in the 2016-17 flu season.

RESULTS

1007 participants completed the survey, sex distribution was even, 67% had 25-44years of age, and 61% annual household income of $30-99 thousand United States dollars. About 25% had the flu shot offered at their workplace and 20% reported belonging to a group for whom the flu shot is recommended. Vaccine uptake was 31.5%. Eight predictors remained in the final adjusted model (R=0.489), having the vaccine offered at the workplace, belonging to a group for whom the vaccine is recommended, and higher perceived barriers were the strongest predictors of vaccine uptake, increasing (and decreasing in the case of barriers) the odds by >3-fold. Additionally, higher household income, higher perceived susceptibility and higher perceived benefits also independently predicted vaccine uptake.

DISCUSSION

We found evidence that perceived barriers significantly impaired vaccine uptake to the same extent that having the vaccine offered at the workplace or belonging to a group for whom the vaccine is recommended facilitated uptake. Ideally, a better understanding of drivers of vaccine hesitancy will result in improved interventions to increase vaccine uptake.