Institutional (Dis)Trust and Online Participation Roles in Vaccination Communication as Public Engagement

The study explores lay online participation in multivocal risk and crisis communication. It looks specifically at how institutional trust shapes such participation in the context of public health risks and crises. Taking the case of vaccination communication as a public engagement site, the study draws on in-depth interviews with Swedish Facebook users communicating about vaccination issues online and investigates how trust in the benevolence and competence of authorities and news media effect lay online participation. The results indicate coexisting trust and distrust when positive expectations regarding one of the dimensions (benevolence) are present alongside negative expectations regarding the other (competence). The study also demonstrates how particular trust beliefs shape online participation by identifying and describing three prominent roles deriving from these beliefs: the critics (low trust in benevolence), the ambassadors (high trust in benevolence), and the mediators (low trust in competence). Finally, the paper discusses the theoretical and practical implications of how these roles can impact multivocal risk and crisis communication in the digital environment.


Introduction
When various risks appear and crisis strikes in a digital society, to a large extent, communications about the unfolding situation and recommended courses of action occur online, not least in social media (Germani and Biller-Andorno 2021). The modern digital media environment provides an infrastructure for a complex rhetorical arena, a communication space in which multiple actors converse about a particular issue (Frandsen and Johansen 2016). For example, the topic of vaccination can be communicated by authorities, the news media, and lay social media users. In this context, authorities aim to provide timely and accurate information on how to protect oneself, limit risks, mitigate damage and save lives. Authorities can communicate directly through their social media accounts; however, they often depend on news media to disseminate as much relevant and correct information as possible (Johansson and Odén 2018). Concurrently, news media rely on authorities as an official information source, especially when emergencies complicate information gathering and validation.
In times of crisis, efficient communication requires coordinated efforts by various stakeholders, including officials, affected organisations, and experts, to "speak with one voice" to reduce conflicting messages and maintain accuracy (Sellnow and Seeger 2021). However, the complexity of communication flows on social media is enhanced by laypeople, whose participation in risk and crisis communication (RCC) alongside various institutional actors grows in scope and visibility (Boulianne 2015). In crises, citizens not only seek relevant and timely information (Sellnow and Seeger 2021) but also discuss it in commentary threads and contribute with their own content (Ansah 2022), a process which can influence interpretations of official messages (Coombs and Holladay 2014). It results in a growing role of lay online participation in RCC. Such participation exists outside traditional organisational or institutional boundaries (Hara and Sanfilippo 2017) and comprises a selfinitiated behaviour to take on specific communicative roles (Bimber 2017).
Previous research has investigated incentives for online participation in general (Boulianne 2015) and also within the context of RCC (Austin, Liu, and Jin 2012;Rodin 2022). Yet, less is known regarding the importance of trust in shaping and influencing online participation (Fletcher and Park 2017).
The role of trust is multifaced: it is an essential mediator for information perception (Renn and Levine 1991) and behavioural choices, such as compliance with public health recommendations (Johansson et al. 2021). In times of risks and crises, available information is limited and uncertainty is high, therefore, individuals are forced to accept uncertainty and vulnerability and to trust recommendations from expert systems (Giddens 1994). Also, trust promotes and stimulates a general culture of participation (Newton 2001), but the ways trust shapes lay online participation roles in the RCC context remain underresearched. This study contributes to filling this knowledge gap.
The explorative nature of the study requires a qualitative approach, which could be a valuable addition to the heavily quantitative trust research (Valentini 2020). To limit the impact of additional situational factors, the study draws on in-depth interviews with social media users actively participating online in the specific context of vaccination communication in Sweden.

Vaccination Communication
The current study adheres to a context-specific approach to RCC (Schwarz, Seeger, and Auer 2016), in which the study design stipulates relevant communication around a particular issue. Vaccination is a prominent long-term topic on the health communication research agenda, which the recent COVID-19 pandemic has further triggered. Being an efficient tool to prevent and mitigate public health damage caused by infection, vaccination has been described as the single most life-saving innovation in the history of medicine (Richter 2015). However, it has been debated since its discovery (Offit 2012). Although the medical community agrees on the prevalence of vaccination benefits over its potential risks, some individuals remain critical. As a result, despite the growing access, vaccines are under-used and under-valued (Ehreth 2003) to the extent that vaccine hesitancy is among the top ten threats to global health (WHO 2019). This study is delimited to the national context of one of the Scandinavian countries, Sweden. The case presents a country with generally high vaccination rates and institutional trust (Ihlen, Johansson, and Blach-Ørsten 2022), which in recent decades experienced several local outbreaks of vaccine-preventable diseases, such as measles, owing to low vaccination rates in specific communities .

VACCINATION COMMUNICATION AS PUBLIC ENGAGEMENT
Communication regarding vaccination encompasses discourse on both risk and crisis. An example of the former is the established national immunisation programs; communication informs and alerts the public about health risks so that they can make informed vaccination decisions. The latter applies to vaccination in the context of outbreaks, as in the COVID-19 pandemic. It focuses on action guidance to mitigate physical and psychological health damage, save lives, and prevent the disease from spreading (Sellnow and Seeger 2021).
Trust in authorities and the news media have been proposed as key factors in vaccination communication, as these institutions are the principal sources of information (Casiday 2010). Also, much contemporary communication takes place on social media. In Sweden, Facebook is a widely used forum for online debates and discussions (Eriksson and Olsson 2016). The rhetorical arena (Frandsen and Johansen 2016) regarding vaccination includes official information from authorities, news media, and contributions by lay social media users.

The Swedish Case
In Sweden, vaccination is voluntary, and vaccination rates are among the highest globally (for example, 97% of children are vaccinated (Folkhälsomyndigheten 2021)), which indicates significant levels of institutional trust (Tafuri et al. 2014). However, in recent years there has been a decline in trust (Medieakademin 2018), except during the COVID-19 pandemic, supposedly due to a rally around the flag effect of the health threat (Johansson et al. 2021).
Despite a generally high prevalence of vaccinations, Sweden has a long history of controversy regarding this topic. Intense deliberations on immunisation programs have frequently focused on vaccine safety and possible side effects (Offit 2012). One of the first well-documented public discussions dates back to Stockholm's 1873-1874 smallpox epidemics (Nelson and Rogers 1992). A decade ago, a communication storm was triggered by the side effects of the Pandemrix vaccine. Following its use to combat the 2009 influenza A(H1N1) pandemic, over 300 vaccinated individuals, primarily children, developed narcolepsy, which is a severe and chronic sleep disorder (Vetenskapsrådet 2017). Another recent example concerns the use of vaccines against human papillomavirus infection and their alleged side effects (European Medicines Agency 2020).
Vaccination communication in Sweden comprises a joint responsibility of several authorities. The central role lies within national authorities, such as the Public Health Agency of Sweden and the Swedish Civil Contingencies Agency (MSB) via a collaborative web platform krisinformation.se. Therefore, the study focuses on national state authorities.
Sweden has marked internet penetration: 94% of Swedes use the internet daily (Swedes and the Internet 2021). Over 70% use Facebook, making it the second most popular social media platform in Sweden after YouTube. Numerous public and closed groups on Facebook are devoted explicitly to vaccinations, either to general discussions or exchanges for or against vaccination. These groups range from several hundred to several thousand active users. In addition, intense debates are common in commentary threads on thematic Facebook posts of institutional actors, authorities, and the news media.

Trust, Benevolence and Competence
Trust is a heavily researched concept that has been approached from various perspectives, including behavioural, personality psychology, sociology, economics, and others. Despite contesting definitions and theoretical diversity, scholars agree on its basic components by which trust comprises "the intention to accept vulnerability based on positive expectations of the intentions or behaviour of another" (Rousseau et al. 1998). Lower trust entails greater uncertainty and diminished positive expectations, whereas distrust encompasses confident negative expectations of another's conduct. Thus, trust and distrust are separate constructs that refer to different expectations and may coexist (Saunders, Dietz, and Thornhill 2014).
Trust encompasses an array of sub-constructs: propensity, e.g. inclination to trust; intentions, e.g. to be vaccinated; behaviour, e.g. compliance with official recommendations; and beliefs (Harrison McKnight and Chervany 2001). Previous research suggests that trust is an antecedent for online participation and citizen media production (Moy et al. 2004). In the institutional context, trust refers to the extent to which one believes that an institution is willing and able to act in the trustor's interests (Harrison McKnight and Chervany 2001). This definition highlights two core dimensions of trust, i.e. the perceptions of willingness and ability. The former refers to the benevolence of institutional actions, whereas the latter encompasses competence and its manifestations. Subsequently, for clarity, the dimensions will be referred to as benevolence and competence, respectively. Other scholars suggest additional dimensions of trust in interpersonal or organisational settings, e.g. integrity (Mayer, Davis, and Schoorman 1995), reciprocity (Berg, Dickhaut, and McCabe 1995), and openness or transparency (Frewer 2003). However, despite existing variations, there is a shared assumption that trust includes the dimensions of benevolence and competence (Di Battista, Pivetti, and Berti 2020).
With respect to distrust, expectations will be the opposite: a lack of benevolence and competence. This distinction facilitates the identification of plausibly coexisting trust and distrust (Harrison McKnight and Chervany 2001). For example, trust in the benevolence of an institution may exist alongside distrust in its ability to perform required actions and vice versa.
In the case of vaccinations, particular focus is given to trust in authorities and news media (Casiday 2010). The perception of the benevolence of these institutions to act in the interests of the public is frequently questioned. Authorities and news media are accused of deception, not caring, having a conflict of interests and bias (Offit 2012). One of the reasons for this is the suspected involvement of pharmaceutical companies in public health matters through the funding of scientific research and advertising (Cummings 2014).
News media are often criticised as a result of so-called media logic (Altheide and Snow 1979), which is said to favour sensationalism, human-interest stories and conflicts, among others. For example, sensational headlines on the measles, mumps and rubella vaccine allegedly being connected to autism invoked fear, anxiety and confusion in many parents, resulting in a sizeable reduction in vaccine uptake (Hackett 2008). Moreover, even neutral news reporting, which is considered fair and impartial by a neutral observer, could be perceived as biased, which has been identified as a hostile media phenomenon. Such perception could lead to behavioural outcomes when, for example, people take action when they believe they are being mistreated in the news media (Hansen and Kim 2011).

VACCINATION COMMUNICATION AS PUBLIC ENGAGEMENT
In addition, there is a widespread public view that news outlets exaggerate public health issues or, on the opposite, do not report them (Cummings 2014). Additionally, the news media reporting during the previous public health crisis in Sweden has shown to fail in the critical examination of authorities, their information and decisions (Cornia et al. 2016;Simons 2020).
There are also several issues related to the perception of competence of both authorities and news media. Recent decades have been characterised by the proliferation of information and increasing levels of higher education worldwide. Additionally, patients are positioned as consumers in health care, which contributes to lay people challenging authorities' expertise and attempting to re-appropriate knowledge and skills from the exclusive domain of the medical profession (Hibbert, Bissell, and Ward 2002).
Moreover, news media competencies to report health risks and crises can be linked to an enduring issue with science journalism. For example, in the mid-1980s, after an extensive analysis of media coverage of the diphtheria outbreak in Gothenburg, Sweden, scholars issued calls for more extensive employment of specialised medical reporters, at least in some of the larger newsrooms, to diminish the problem of overly speculative journalism (Hvitfelt 1986). However, the issue remains, as the severe crisis of established economic models of journalism has led to a shrinking market for science journalists.

Online Participation Roles
Previous research indicates that trust influences online participation (Ardèvol-Abreu, Hooker, and de Zúñiga 2018). Online participation refers to "the creation and sharing of content on the internet addressed at a specific audience and driven by a social purpose" (Lutz, Hoffmann, and Meckel 2014, 2). Research confirms that it is a distinct type of participation, as opposed to offline engagement (Oser, Hooghe, and Marien 2013), and a spectrum of participatory behaviour composes different roles. Faraj, Jarvenpaa, and Majchrzak (2011) define roles in online participation as the enactment of temporary sets of behaviours that are voluntarily engaged in, self-defined, and inductively created for online participation (p.1231). This definition draws on Goffman (1959) and emphasises the emergent and enacted nature of the roles in specific situational contexts (for instance, in vaccination communication).
The COVID-19 pandemic brought significant attention to RCC in the public health context through official communication and online participation. For example, Finland was one of the first countries in the world to embrace online participation facing this communication challenge. In March 2020, the Prime Minister's Office initiated The Corona Facts campaign that engaged social media influencers in urgent health communication. Pöyry, Reinikainen, and Luoma-Aho (2022) identified a two-fold role of influencers: (1) information redistribution to niche audiences; (2) fostering pandemic-related socio-behavioural norms (e.g. limited social gatherings, travel, and new hygiene routines). Other countries followed; for instance, in Portugal, 5,000 micro-influencers were recruited and trained by the authorities to provide trusted sources of information regarding vaccination against the COVID-19 virus (WHO 2022). These examples show increasing interest for RCC practitioners to efficiently integrate online participation on social media into communication campaigns.
The existing body of research on online participation roles primarily focuses on online discussion groups and knowledge collaboration (e.g. Wikipedia entries) (Hara and Sanfilippo 2017). The roles are often identified by content analysis and network analysis methodology based on specific functions of participatory contributions. Examples of such roles are the organiser, helper, supporter, unmasker, reframer, and mediator (Faraj, Jarvenpaa, and Majchrzak 2011;Karanasios and Zorina 2023). The present study further expands this line of research with the concept of trust.
Against this background, the current study investigates in what ways trust in the benevolence and competence of (i) authorities, and (ii) the news media shape lay online participation in communication about vaccination in Sweden?

Method
The study relies on the use of personal interviews to answer the research question, as this technique has proven suitable for exploratory research (Miles and Huberman 1994). Interviews enable participants to describe their perceptions and beliefs, offering a deep, contextualised understanding of experiences, such as motivations, that cannot be observed directly (Brinkmann and Kvale 2015).
Interview participants (IPs) were recruited purposively to collect research data with high information power (Malterud, Siersma, and Guassora 2016). A set of criteria was imposed to target a highly specific sample of individuals with experiences that can be magnified and that would yield analytic value. The subjects had to meet the following selection criteria: (i) participation in communication about vaccinations on Facebook; (ii) a clearly expressed attitude towards vaccination which was either favourable or critical; and (iii) a high degree of communicative activity on Facebook, i.e. regular and frequent contributions to theme-specific groups or pages by creating/sharing posts or leaving comments.
Data collection was commenced by setting up a tailor-made Facebook account to secure the anonymity of all participants. All relevant public and semi-public Swedish Facebook groups, searchable and visible for non-group members, were identified through a general search. These groups welcomed all users, e.g. Vaccindiskussioner ["Vaccine discussions"], or targeted ones with particular positions or experiences, for instance, Vaccinkriget (V-kriget) ["The Vaccine War"] and Vaccinationens baksida ["The Downside of Vaccination"]. The most active users creating content and participating in discussions from all relevant groups were contacted. They received a brief interview invitation linked to a full study description on a university web page. To alleviate any potential mistrust, those contacted were also informed that the study focused on social media use and not on vaccination per se, and that neither Swedish public health authorities nor Facebook funded the research.
The interview grid consisted of two sections. The first focused on overall experiences of communicating about vaccination on Facebook, i.e. in groups or pages, activity over time and forms of participation. The second delved into trust in authorities and news media in relation to online participation and its motivations. Interviewees were not asked for any sensitive personal data as defined in §1 Article 9 of the GDPR (General Data Protection Regulation 2016).
All IPs gave informed consent to be interviewed and audio recorded. The collection of interviews was guided by the exploration logic (Malterud 2001), meaning that it did not aim at fully describing all aspects of the phenomenon under investigation but rather at offering new insights contributing to a better understanding of lay online participation. In the current study, in total, eleven interviews with participants from a highly specific VACCINATION COMMUNICATION AS PUBLIC ENGAGEMENT sample were collected. The collection of interviews continued until the gathered data reached a point when no new thematic codes emerged. A statistical meta-analysis of thematic saturation for interview datasets by Guest, Bunce, and Johnson (2006) indicates that most data saturation occurs within twelve interviews.
The interviews were conducted in Swedish, transcribed, and anonymised. The transcripts were systematically analyzed following Miles and Huberman's (1994) data-analysis procedures: data reduction, data display and conclusion drawing/verification. Interview transcripts were continuously inductively coded in NVivo 12 during the data reduction phase. During data display, these codes were clustered together into topics relating to the analyzed trust attitudes and institutions. Lastly, the topics were reviewed to identify possible multiple meanings and interpretations.
The mean interview length was 41 minutes. Interviews were conducted via Skype/ FaceTime (6), telephone (2), face-to-face (2), or Facebook Messenger (1), depending on each informant's preferences. The interviews were conducted under different situational contexts: during the measles outbreak in Gothenburg in 2018 (5), prior to the COVID-19 pandemic in 2019 (4); and during the COVID-19 pandemic but before the vaccination program commenced in 2020 (2). Information about the IPs is presented in Table 1.

Results
This section presents specific ways that trust in the benevolence and competence of authorities and news media shape lay online participation, and the following section further analyses these results and identifies prominent roles.

The Benevolence of Authorities
Interview analysis showed that the perception of the benevolence of authorities in Sweden with respect to vaccination communication was frequently characterised by negative expectations (distrust). Some users cited corruption and connections to the pharmaceutical industry. Interviewees further elaborated that such financial interests overweight "the care for ordinary people" (IP2) and the public interest. 1 Frequently, the communication from authorities was perceived as biased and onesided. It motivated social media users to intervene in vaccination communication in open public arenas on Facebook and to criticise such information. According to their position, such participation aimed to challenge the one-sidedness and restore balance by providing alternative information and facts (which they considered unbiased).
Unfortunately, in my view, the authorities have become more propagandistic by providing a very one-sided version. They only talk about benefits but not about vaccination risks […] but there is no risk-free medicine. (IP6) The interviewees also pointed out that recommendations from authorities in Sweden rely on only a few experts and lack a broader dialogue between scientists and laypeople. This engenders a perception of a closed system of decision-making. The culture of Swedish authorities was suggested to lie behind a somewhat reluctant attitude towards public debates on official decisions.
It is perhaps a combination of the Swedish culture and the culture of Swedish authorities; you should be credible and neutral, protect everyone and mean everyone well. But it can contradict that sometimes you have to stand up for your decisions. It would be good to take the debate. (IP4) Another concern was that authorities' recommendations were standard and overly general, disregarding individual differences and personal circumstances. Once again, this view triggered social media users to share personal stories and experiences to expand vaccination communication from additional angles.
The interviewees supporting vaccination appeared to hold overall positive expectations of the benevolence of authorities. Yet they admitted that the authorities were widely perceived as unreliable, and that this discrepancy triggered online participation. Their participation aimed to compensate for the trust deficit in authorities and to represent the official line of information on social media. One of the interviewees explained: In such a situation, people do not want to listen to someone who gets paid for saying X and Y, but rather to another layperson who created his or her own truth. Yet, I wish people could listen to authorities or experts on the matter. (IP1)

The Competence of Authorities
The perceived competence of the authorities varied among the interviewees; several concerns regarding vaccination communication by authorities were raised. Noteworthy, the criticism was usually accompanied by suggestions aimed at authorities and other lay social media users. Some interviewees stated that the authorities were unable to reach larger audiences due to their limited presence in relevant commentary threads and discussions on social media. One interviewee told: Authorities fail to be present on social media. They have to be more active there. Not just in some important things, which are visible anyway, but to show their presence even in small things. To demonstrate some form of compassion, they care about the little person. By doing so, they will build trust. (IP2) This triggered social media users with high trust in the benevolence of authorities to assist in disseminating official messages via diverse social media channels.

VACCINATION COMMUNICATION AS PUBLIC ENGAGEMENT
Also, interviewees stressed the importance of language. For example, authorities often employed overly formal language filled with medical and bureaucratic terminology that was difficult to grasp. Thus, several social media users rephrased and translated official messages into language that was more easily understood and shared this on social media to mediate official information dissemination to larger audiences.
I think it is difficult to understand too much medical or difficult language for any layperson without medical education. Indeed, communication is more precise with official or medical terminology. But why couldn't we have both? When you click in, you get into easy-to-read information, and then you can click further if you want to access more. (IP5) Another concern was that the authorities were impersonal, which affected communication effectiveness. This concern stimulated some interviewees to complement institution-to-person communication on social media with person-to-person communication.
Sometimes, it is just not enough to get information from an institution. I believe that for such issues as vaccination, interpersonal communication is vital. Then it will be personal in a completely different way. (IP1)

The Benevolence of the News Media
Transcript analysis revealed multiple concerns regarding the benevolence of the news media affecting online participation. One of the critical issues described was that the news media failed to show a representative image of reality. The news media were perceived as frequently focusing on human-interest stories, conflicts and sensations. Simultaneously, many important facts and events concerning vaccinations were missing in the reportage. Instead, the news media appeared to look for controversies and debates, which may have led to the spread of misperceptions. The following quotes discussed these concerns: The news media surely want to have conflicts. That's what the media live on. It is what gets sold. It is interesting, I agree, but it gives a false representation. (IP2) The news media want to discuss or debate vaccines; it provides clicks as it is presented as being controversial. But it's not a controversy. The problem is that when the media do so often, it is perceived as controversial. (IP4) Furthermore, participants felt that giving equal time to people with different positions on vaccination was unfair, building up a false balance in vaccination debates and providing a skewed representation of reality.
The issue with vaccination coverage is that supporters and opponents get equal space. However, vaccination opponents are relatively few but very active. Yes, the media must present both sides, the pros and cons. But they still have to be well-balanced and representative. I do not think that is always the case. (IP5) On the other side, some interviewees argued that often media reports on vaccinations were biased, one-sided and lacked neutrality. The journalists were criticised for being over-positive and uncritical toward immunisation. An interviewee noted: Journalists must put their own opinion aside as far as possible. However, I see very clearly that many don't do so regarding vaccination. I think it's sad. (IP7) On top of that, the interviewees noted that journalists often ridiculed the few vaccine-critical voices that appeared in the news media. This could be performed directly by a journalist or by a commentary from vaccination experts that dismantled the argumentation of vaccine opponents.
It's all about vaccine opponents getting to say something, after which the journalist calls a professor who will ridicule all that has been said. (IP6) Since media reports on vaccination were perceived as biased and one-sided, the interviewees employed social media to open up new discussion spaces which could present alternative views and positions absent in the news. The participation was further stimulated as Facebook affordances increased the visibility and the accessibility of such lay user contributions to large audiences. The following quotes describe these views: I get furious; you miss the point! Then I go to the commentary field and type in my comment. (IP2) Previously, I could write an email to a newspaper, but that would simply disappear. Comments and posts on Facebook are public and visible to everyone. That's why it is crucial for me to participate online. (IP3)

The Competence of the News Media
Interview analysis indicated the concern focused on journalists' limited skills in scientific reporting, which omitted cutting-edge medical research on vaccination from being covered. The interviewees also argued that the Swedish mainstream news media mostly reported on vaccination following a single track. Thus, people are urged to find ways to expand their media consumption to discover the broader picture and to access various positions on the issue.
In Sweden, all mainstream media follow the same pattern, especially on controversial issues, such as vaccination. And if you want to learn something, you must look around. I turn to alternative media and read foreign press every day. (IP11) Also, the perceived competence of the news media significantly varied across different news outlets, both quality newspapers and tabloids. An interviewee brought the example of tabloids and suggested that they were prone to sensational reporting and human-interest stories. The interviewee further elaborated: Look at tabloids! Sometimes I am very frustrated when they have an excellent article alongside a very alarmist text about vaccination. (IP1)

Analysis and Discussion
Based on the study results, it is possible to identify three prominent online participation roles of public engagement in the context of communication about vaccination shaped by different trust attitudes. These roles are the Critic, the Ambassador and the Mediator.
The communicative behaviour of the Critic is characterised by disputing and questioning official information and the news media coverage of vaccination issues. Lay

VACCINATION COMMUNICATION AS PUBLIC ENGAGEMENT
social media users take on this role when they have low trust or high distrust in the benevolence of authorities and/or news media. This attitude encourages users to doubt official recommendations and views on vaccination. Such users may also pinpoint discrepancies and biases in the news media, which are perceived to convey official information and to provide a predominately one-sided coverage. In line with previous research, the activities of these users aim to overcome the influence of untrustworthy media (Moy et al. 2004;Fletcher and Park 2017).
In RCC practice, it is crucial to monitor Critics' concerns on social media to identify possible weak points in communication that can escalate into larger issues and to establish two-way communication for improving institutional credibility and the effect of RCC (Renn and Levine 1991). Additionally, dealing with online critique is crucial to prevent the potential effects of a reinforcing spiral of distrust, which means that when the public post negative comments criticising the authorities, this may reduce the level of public trust in these institutions (Zhu et al. 2020).
Another identified role is that of the Ambassador. In contrast to the Critic's remit, these participants hold high trust in the benevolence of authorities and voluntarily endorse and promote official RCC information but remain independent and unaffiliated. They act as faith holders (Johansen, Johansen, and Weckesser 2016), who admit that other social media users do not share the same attitude, and their online communication aims to compensate for the deficit of institutional trust. The study results showed that the Ambassadors take part in various debates and discussions on social media as a result of the absence of institutional representatives in these spaces. These users also pointed out that official RCC information is often generalised and that they attempt to humanise by adding a personal dimension.
Previous studies have demonstrated that the lack of authorities' participation in social media leads to an increased prevalence of rumours and fake news (Ansah 2022) and provides an opportunity for hostile and distorted comments to be posted by the public (Tirkkonen and Luoma-aho 2011). The current study cannot determine whether the Ambassadors can compensate for these possible adverse effects. Nevertheless, this cohort can increase the presence of official information on social media through the processes associated with user-generated visibility (Singer 2014). Existing research has highlighted the participation of medical professionals and political leaders in vaccination communication (Zhang et al. 2019). However, the potential of Ambassadors to promote and support institutional RCC is often overlooked and yet to be fully explored by communication professionals.
The third role identified in the study is that held by the Mediators. This online participation role had been found in previous research (Hara and Sanfilippo 2017). However, the present study expands the understanding and the behaviour connected to this role. The trust profile of this group is high trust in benevolence but low trust in the competence of authorities and the news media. In contrast to the Critic, this role focuses on communicating efficiently, reaching target audiences and using appropriate language. The essence of this function is to mediate official information to the general public by disseminating it (so-called user-distributed content (Villi 2012)) and/or making it more comprehensible. By taking on the Mediator role, lay social media users become information brokers (Rodin 2022) and make decisions to re-disseminate content selectively from authorities, news media and even other users as secondary gatekeepers (Singer 2014). Mediators also translate or adapt official information by employing a more easily understood language.
Relying on the Mediators implies a dependency on the choice of information to be re-circulated as well as their qualifications in order to understand and translate medical and official language correctly. As a result, this participation can upgrade the visibility and accessibility of the selected pieces of information and contribute to the effectiveness of RCC. However, it can also contribute to the spread of inaccurate information and interpretations (Leader et al. 2021). Communication practitioners need to be cautious about the Mediators' potential in RCC.
Previous RCC research thoroughly analysed obligations, roles and strategies of authorities and news media in risks and crises. However, the multivocal approach to RCC states that the rhetorical arena on social media does not privilege official institutional voices (Coombs and Holladay 2014). In this complex media environment, the growing attention is directed to emergent lay online participation by social media users. This study expands the theoretical model of the rhetorical arena (Frandsen and Johansen 2016) by exploring lay online participation and documenting that different trust attitudes towards the benevolence and competence of authorities and news media shape different online participation roles: the critics, the ambassadors, and the mediators. Although the limited sample does not allow the results to be generalised, the identified broad contours of the three participation roles offer a foundation for further quantitative analysis. Further research also needs to validate these findings across other public health issues, different RCC contexts, and countries with varying levels of institutional trust in authorities and news media. Additionally, further research can include other dimensions of trust, such as integrity and transparency, and other forms of trust which can impact online participation, for instance, interpersonal trust and trust in social media platforms and technologies.