BACKGROUND: COVID-19 vaccine preferences can influence vaccine coverage. Discrete choice experiments (DCE) can be used to elicit people’s trade-offs. DCEs require evidence-based attribute selection and validation of understanding with lay audiences. To inform a future DCE, a pre-test was conducted to examine the survey and refine six attributes selected from a targeted literature review and expert interviews.
METHODS: Interviews were conducted in March 2023 in Canada, Germany, the UK, and US. Self-reported anti-vaccinationists were excluded. Eligible individuals were interviewed during the completion of a survey that included 11 choice tasks and supplementary questions. The “think aloud” method was used to evaluate participants’ understanding of the survey and if they were making trade-offs as hypothesized. Four country-level experts validated the survey modifications based on the results.
RESULTS: Six phone interviews were completed in each country (N=24). Mean age was 43.7; 50% were women; 50% reported receiving the full COVID-19 vaccine series; 45.8% received the initial series but were unsure about additional doses; 1 was unvaccinated (4.2%). Participants’ top four priorities were vaccine protection against COVID-19, serious side-effects, protection against severe COVID-19, and common side-effects, followed by vaccine type and timing of COVID-19/influenza vaccines (Fig 1). More than half of the participants would consider co-administration of COVID-19 and influenza vaccines, either as two separate injections (58.3%) or as a single, combined injection (62.5%) (Fig 2a). Most individuals (54.2%) preferred an annual COVID-19 vaccine; over every 6 months (4.2%), and 20.8% were indifferent (Fig 2b). When deciding to get vaccinated, most considered the following to be important: how long a vaccine was examined in humans (65.2%), how long a vaccine was used in a vaccination program (62.5%); 50% considered vaccine type (mRNA or protein subunit) important (Fig 3).
CONCLUSION: This study validated the importance of key vaccine attributes driving people’s choices and feedback was used to improve the clarity of attribute descriptions. A future DCE will be fielded to increase the understanding of COVID-19 vaccine preference and hesitancy.
