Background Automated conversational agents, or chatbots, have a role in reinforcing evidence-based guidance delivered through other media and offer an accessible, individually tailored channel for public engagement. In early-to-mid 2021, young adults and minority populations disproportionately affected by COVID-19 in the United States were more likely to be hesitant toward COVID-19 vaccines, citing concerns regarding vaccine safety and effectiveness. Successful chatbot communication requires purposive understanding of user needs. Objective We aimed to review the acceptability of messages to be delivered by a chatbot named VIRA from Johns Hopkins University. The study investigated which message styles were preferred by young, urban-dwelling Americans as well as public health workers, since we anticipated that the chatbot would be used by the latter as a job aid. Methods We conducted 4 web-based focus groups with 20 racially and ethnically diverse young adults aged 18-28 years and public health workers aged 25-61 years living in or near eastern-US cities. We tested 6 message styles, asking participants to select a preferred response style for a chatbot answering common questions about COVID-19 vaccines. We transcribed, coded, and categorized emerging themes within the discussions of message content, style, and framing. Results Participants preferred messages that began with an empathetic reflection of a user concern and concluded with a straightforward, fact-supported response. Most participants disapproved of moralistic or reasoning-based appeals to get vaccinated, although public health workers felt that such strong statements appealing to communal responsibility were warranted. Responses tested with humor and testimonials did not appeal to the participants. Conclusions To foster credibility, chatbots targeting young people with vaccine-related messaging should aim to build rapport with users by deploying empathic, reflective statements, followed by direct and comprehensive responses to user queries. Further studies are needed to inform the appropriate use of user-customized testimonials and humor in the context of chatbot communication.

Effective strategies to encourage COVID-19 vaccination should consider how health communication can be tailored to specific contexts. Our study aimed to evaluate the influence of three specific messaging appeals from two kinds of messengers on COVID-19 vaccine acceptance in diverse countries. We surveyed 953 online participants in five countries (India, Indonesia, Kenya, Nigeria, and Ukraine). We assessed participants’ perceptions of three messaging appeals of vaccination—COVID-19 disease health outcomes, social norms related to COVID-19 vaccination, and economic impact of COVID-19—from two messengers, healthcare providers (HCP), and peers. We examined participants’ ad preference and vaccine hesitancy using multivariable multinomial logistic regression. Participants expressed a high level of approval for all the ads. The healthcare outcome–healthcare provider ad was most preferred among participants from India, Indonesia, Nigeria, and Ukraine. Participants in Kenya reported a preference for the health outcome–peer ad. The majority of participants in each country expressed high levels of vaccine hesitancy. However, in a final logistic regression model participant characteristics were not significantly related to vaccine hesitancy. These findings suggest that appeals related to health outcomes, economic benefit, and social norms are all acceptable to diverse general populations, while specific audience segments (i.e., mothers, younger adults, etc.) may have preferences for specific appeals over others. Tailored approaches, or approaches that are developed with the target audience’s concerns and preferences in mind, will be more effective than broad-based or mass appeals.

Throughout the COVID-19 pandemic, vaccine communication has been a challenge, particularly as some populations may be highly distrustful of information from public health or government institutions. To better understand the different communication needs in Ukraine, an online survey panel of 168 Ukrainian participants viewed six COVID-19 vaccination ads with three variations on vaccine messaging appeals (potential economic impacts of COVID-19 infection COVID-19 disease outcomes, and social norms related to vaccination) and two different messengers (a peer or a health provider). The ad featuring a health outcome appeal delivered by a healthcare provider was most favored (n = 53, 31.6%); however, across demographic categories, including vaccine hesitancy categories, participants expressed high levels of approval for all six variations of the COVID-19 vaccine ads. When participants ranked reasons why someone may not accept the COVID-19 vaccine, the most prevalent beliefs identified were that the vaccine was not safe, and that the vaccine was not effective. Findings from this study suggest that vaccine appeals focused on health outcomes delivered by healthcare providers are preferred by most individuals in Ukraine; however, individuals are motivated by a myriad of factors suggesting that for vaccine messaging to be most effective, communication should be varied in both appeal and messenger.

BACKGROUND Automated conversational agents, or chatbots, have a role in reinforcing evidence-based guidance delivered through other media and offer an accessible, individually tailored channel for public health guidance. In early-to-mid-2021, young adults and Black and Hispanic community members in the U.S. were more likely to be hesitant toward COVID-19 vaccines, citing concerns regarding vaccine safety and effectiveness. Successful chatbot communication requires purposive understanding of user needs, and little is known about how vaccine messaging should be delivered by educational chatbots in health contexts. OBJECTIVE We sought to review the acceptability of messages to be delivered by a chatbot named VIRA from Johns Hopkins University. The study investigated which message styles were preferred by young, urban-dwelling Americans as well as public health workers, since we anticipated the chatbot would be used by the latter as a job aid. METHODS We conducted four virtual focus groups with 20 racially and ethnically diverse adults 18-61 years old living in or near eastern U.S. cities. We tested six message styles, asking participants to select a preferred response style for a chatbot answering common questions about COVID-19 vaccines. We transcribed, coded, and categorized emerging themes within discussions of message content, style, and framing. RESULTS Participants overwhelmingly preferred responses that began with an empathetic reflection of a user concern and concluded with a straightforward, fact-supported response. Most participants disliked moralistic or reasoning-based appeals to get vaccinated, although a subset of public health workers felt such strong statements were warranted. Responses containing humor, testimonials, or unsympathetic phrases did not appeal. CONCLUSIONS To foster credibility, chatbots targeting young people should aim to build rapport with users by deploying empathic, reflective statements, followed by direct and comprehensive responses to user queries. Further studies are needed to inform the appropriate utilization of user-tailored testimonials and humor in the context of chatbot communication, since these strategies can effectively engage and influence users through social media and other digital communication media.

Few studies have examined the relationships between the different aspects of vaccination communication and vaccine attitudes. We aimed to evaluate the influence of three unique messaging appeal framings of vaccination from two types of messengers on COVID-19 vaccine acceptance in India. We surveyed 534 online participants in India using Amazon Mechanical Turk (MTurk) from December 2021 through January 2022. We assessed participants’ perception of three messaging appeals of vaccination – COVID-19 disease health outcomes, social norms related to vaccination, and economic impact of COVID-19 - from two messengers, healthcare providers (HCP) and peers. Using a multivariable multinomial logistic regression, we examined participants’ ad preference and vaccine hesitancy. Participants expressed a high level of approval for all of the ads, with >80% positive responses for all questions across ads. Overall ads delivered by health care workers were preferred by a majority of participants in our study (n = 381, 71.4%). Ad preference ranged from 3.6% (n = 19) social norm/peer ad to 32.4% (n = 173) health outcome/HCP ad and half of participants preferred the health outcome ad (n = 279, 52.3%). Additionally, vaccine hesitancy was not related to preference ( p = .513): HCP vs. peer ads ( p = .522); message type ( p = .284). The results suggest that all three appeals tested were generally acceptable, as well as the two messenger types, although preference was for the health care provider messenger and health outcome appeal. Individuals are motivated and influenced by a multitude of factors, requiring vaccine messaging that is persuasive, salient, and induces contextually relevant action.