Factors contributing to whether US adults would accept a coronavirus disease 2019 vaccine (COVID-19) were discussed in a recently published survey study.
As widespread public acceptance of a COVID-19 vaccine is imperative to stem the pandemic, the study aimed to determine factors that increase the likelihood of US citizens choosing and receiving a hypothetical vaccine. The study, which included 1971 US adults, utilized a choice-based conjoint analysis to estimate the participants’ probability of choosing as well as receiving a COVID-19 vaccine.
In the 5 choice tasks presented in the survey, respondents analyzed 2 hypothetical vaccines and were asked which vaccine option they would choose (vaccine A, B, or neither). Attributes related to the vaccine that were analyzed included efficacy, duration of protection, major and minor adverse effects, Food and Drug Administration (FDA) approval process, vaccine national origin, as well as endorsement.
For each vaccine, levels of each attribute were randomly assigned and attribute order was also randomized across respondents. To estimate the association between attribute level and probability of choosing and receiving a vaccine, the study authors calculated the average marginal component effects sizes as well as marginal means.
The median age of patients included in the study was reported to be 43 years (interquartile range, 30-58); 51% of respondents were women, 73% were White, 14% were Black, and 10% were Latinx.
Findings of the survey revealed an increase in vaccine efficacy from 50% to 70% (coefficient, 0.07; 95% CI, 0.06-0.09) as well as from 50% to 90% (coefficient, 0.16; 95% CI, 0.15-0.18) were associated with a higher probability of choosing a vaccine. Additionally, the authors reported that an increase in the duration of vaccine protection from 1 to 5 years (coefficient, 0.05; 95% CI, 0.04-0.07) and a decrease in the incidence of major adverse effects from 1 in 10,000 to 1 in 1,000,000 (coefficient, 0.07; 95% CI, 0.05-0.08) were also associated with a higher probability of choosing a vaccine.
Results of the study also showed that, compared with an endorsement from President Trump, vaccine endorsements from the US Centers for Disease Control and Prevention (CDC) (coefficient, 0.09; 95% CI, 0.07-0.11) and the World Health Organization (WHO)(coefficient, 0.06; 95% CI, 0.04-0.08) were associated with higher probabilities of choosing a vaccine. Results of the survey also showed that a vaccine approved by FDA emergency use authorization, compared to full FDA approval, and a vaccine developed in a non-US country, especially China, were associated with lower probabilities of choosing a vaccine.
“Analyses of participants’ willingness to receive each vaccine when assessed individually yielded similar results,” the authors reported. Findings revealed an increase in vaccine efficacy from 50% to 90% to be associated with a 10% higher marginal mean willingness to receive a vaccine (from 0.51 to 0.61), while a decrease in the incidence of major adverse effects was associated with a 4% higher marginal mean willingness to receive a vaccine (from 0.54 to 0.58).
Additionally, increases in willingness to receive a vaccine were observed for vaccines endorsed by the CDC (7%) and the WHO (6%) from a baseline endorsement from President Trump. Findings of the survey also revealed that a vaccine developed in China was associated with a 10% lower willingness to receive a vaccine compared with one originating in the US (from 0.60 to 0.50).
“In this survey study of US adults, vaccine-related attributes and political characteristics were associated with self-reported preferences for choosing a hypothetical COVID-19 vaccine and self-reported willingness to receive vaccination,” the authors concluded. “These results may help inform public health campaigns to address vaccine hesitancy when a COVID-19 vaccine becomes available.”
Kreps S, Prasad S, Brownstein JS, et al. Factors associated with US adults’ likelihood of accepting COVID-19 vaccination. JAMA Network Open. 2020;3(10):e2025594. doi: 10.1001/jamanetworkopen.2020.25594.