Promoting COVID-19 Vaccination: The Interplay of Message Framing, Psychological Uncertainty, and Public Agency as a Message Source

"As misinformation and uncertainty have infiltrated the public space, this study aims to provide useful knowledge for public agencies about how to communicate effectively with the public...and maximize campaign effectiveness."

The question of how to use different message strategies to encourage vaccination uptake has been the subject of communication research. This matter takes on practical import in light of vaccine hesitancy. Compared with long-existing vaccines such as the oral polio vaccine, the novelty of COVID-19 vaccines using messenger RNA (mRNA), coupled with conspiracy beliefs that spread rapidly via social media, has fueled public uncertainty about safety and efficacy. This study examines how message framing, psychological uncertainty, and the type of agency serving as message source influence COVID-19 vaccination promotion.

A literature review opens the paper and explains the key concepts being investigated in the study. Namely:

• Framing research investigates how different strategies of message construction influence individuals' cognitions, attitudes, and behaviours. The research on gain-loss frames suggests that individuals are more likely to take risks when considering the possible losses associated with a decision, yet they tend to be risk-averse when the provided information emphasises potential gains. Researchers have highlighted potential shortcomings of loss-framed appeals in persuasion. By advocating a particular behavioural choice, persuasive messages may be perceived as a threat to freedom and elicit psychological reactance, typically in the form of counterarguing against the persuasive attempts and anger.
• Psychological uncertainty refers to a state of insecurity in one's state of knowledge. It is a self-perception that individuals generate about their cognitions or ability to make judgments when exposed to information that is insufficient, ambiguous, complex, or inconsistent. Different levels of experienced uncertainty determine how individuals process information about COVID-19 vaccination.
• Public health agencies are the primary sources for vaccination information and public education. As individuals increasingly turn to social media for health information, particularly during emerging health crises, social media have become a key channel for public agencies to use communicate vaccine-related information. Agencies at different levels - from national agencies to local public health departments - have maintained an active presence during the COVID-19 pandemic. It is possible that, being geographically closer, a local health agency may be perceived as a proximal source and make the campaign message appear more relevant to individuals compared with a national agency.

The data for this study were collected in mid-December 2020, around the time the first two COVID-19 vaccines were approved under Emergency Use Authorization in the United States (US). The researchers conducted a 2 (gain vs. loss frame) × 2 (high vs. low uncertainty) × 2 (national vs. local agency) between-subjects experiment among 382 US residents. The stimuli included four versions of a simulated tweet that described the efficacy of the first two COVID-19 vaccines in the US in clinical trials and the possible timeline of their availability. It also discussed the benefits of vaccination or the harms of not being vaccinated. The format, design, information, and social media metrics (i.e., number of likes, comments, and retweets) of the tweet were maintained the same across conditions except for the experimental manipulations. Details:

• Gain-loss frames were operationalised by emphasising either the positive outcomes of vaccination (i.e., substantially reduced chances of infection and severe complications) or the negative consequences of not being vaccinated (i.e., significantly increased chances of infection and severe complications) to individuals.
• A thought-listing task "primed" psychological uncertainty. Participants were asked to write about things they felt most uncertain or certain about with regard to COVID-19 vaccines.
• Agency type was manipulated by varying the source of the tweet - national vs. local.

Consistent with prior literature, the study found that the loss-framed message generates a stronger perception of threat to freedom and stronger psychological reactance than the gain-framed message. However, this effect does not necessarily translate into unfavourable persuasion outcomes. Rather, the effect should be understood in the context of the interaction between framing and psychological uncertainty. That is, the gain-framed message is more effective under conditions of low uncertainty, whereas the loss-framed message is more persuasive under conditions of high uncertainty. Put another way: Although participants are more aware of the persuasive attempt of the loss-framed message, they are less affected by it when they made judgments about COVID-19 vaccines under conditions of high uncertainty.

The researchers explain these findings by pointing to the possible influence of psychological uncertainty on the manner of information processing. Experiencing low uncertainty, participants are more likely to engage in heuristic processing (to use mental shortcuts - e.g., relying on peripheral cues such as message tones). Their reactance may thus be elicited by the negative tone of the loss frame. In contrast, high levels of uncertainty may trigger a more deliberate way of message processing. Under this circumstance, negative information outweighs positive information due to the occurrence of negativity bias.

These findings suggest that "distinguishing different ways of information processing and identifying their antecedents may be crucial to further our understanding of framing effects....[N]egativity bias and psychological reactance are not two competing explanations of framing effects. Rather, they may occur under different modes of information processing."

Moreover, there was an interaction effect between uncertainty and agency type on vaccine beliefs. The local agency, as an information source, does lead to more positive beliefs toward COVID-19 vaccines under conditions of low uncertainty than the national agency; people in this case process the message in a more heuristic manner and are more likely to comply with the message when it is from a proximal source (i.e., local agencies). Such an advantage, however, disappears for participants primed with high uncertainty, which may encourage systematic processing that values message quality and is less swayed by the characteristics of a message source, such as proximity.

Practical implications for vaccine promotion include:

• Health practitioners need to consider public uncertainty when constructing campaign frames. For example, as vaccines for emergency use may trigger a higher level of uncertainty, it would be more effective to employ loss-oriented frames. By contrast, when it comes to routine vaccine administration, such as flu or measles vaccines, gain frames may work better.
• Local agencies may be more effective than national ones as sources of risk information in promoting risk-mitigation measures such as vaccine uptake when the public holds more certain beliefs or is less motivated to process campaign messages. Under these scenarios, health campaigns should further leverage the communication capacity of local public agencies to better reach the community served.

In conclusion: "Clearly, as a fundamental message feature, gain-loss frames are consequential to persuasion. But their relative effects are contingent on contextual factors such as psychological uncertainty. More research is needed to elucidate the various 'nuances' of framing effects."