The emergence of social media and online platforms has given rise to a new group of influencers known as digital opinion leaders (DOLs). DOLs are influential figures who are able to shape the opinions and behaviors of their audience across a spectrum of fields through their activities on online platforms [1]. In the context of health care, key opinion leaders (KOLs) are traditionally recognized as experts within their professional fields, often gaining credibility through peer-reviewed publications, academic presentations, and advisory roles in health care and public health institutions. In recent years, a growing number of traditional KOLs have been transitioning into DOLs through their increasing digital presence, while some DOLs, such as early-career professionals, primarily establish their influence online rather than in academia or professional settings [1]. Similar to KOLs, DOLs are usually qualified health care providers [2]. However, in contrast to traditional KOLs, who primarily communicate and influence via conventional channels, such as journal publications or speaking activities, DOLs operate regularly within the digital domain. This enables them to exert influence over a wider and more diverse audience, spanning various communities, including both health care providers and the general population [1,3]. While both DOLs and social media influencers (SMIs) operate on online platforms and engage with diverse audiences, DOLs are a distinct subset of SMIs, characterized by their medical qualifications and commitment to educating the public with evidence-based health information. In contrast, SMIs often lack formal medical training and primarily focus on lifestyle content, trends, and personal experiences, which may not always be grounded in scientific evidence [4]. Table 1 provides an overview of the comparison between KOLs, DOLs, and SMIs.

Recent evidence suggests that leveraging digital platforms holds promise for promoting a range of health behaviors to achieve positive health outcomes [5-7]. For example, SMIs championed and successfully promoted the adoption of preventive measures, including the use of masks, testing, and vaccination during the COVID-19 pandemic in many countries, such as the United States and Finland [8-10]. Despite the many studies on SMIs, those specifically exploring the role of DOLs are limited. One review that examined the use of online influencers to improve the uptake of human papillomavirus vaccines suggested that those with a health or medical background can serve as credible information sources and engage their audience in positive conversations about human papillomavirus, thereby fostering positive attitudes toward human papillomavirus vaccines and countering misinformation [11]. However, the study did not distinguish the definitions of DOLs and SMIs or further highlight their differences [11].

Furthermore, SMIs may offer an avenue for preventing complex diseases, such as dengue. Dengue stands as a major public health challenge, with a substantial global disease burden. Dengue incidence has increased ten-fold in the last 2 decades [12]. According to an update from the World Health Organization (WHO) in 2024, dengue is endemic in >100 countries, putting approximately 3.9 billion individuals at risk of infection [12,13]. Latin America and Southeast Asia are among the regions most affected by dengue globally [14,15]. The average dengue-related cost was reported to be US $2.1 billion annually in the Americas, surpassing the financial burden of many other viral diseases [16]. Particularly, a dengue outbreak in Brazil resulted in more than half a million recorded cases within the first 2 months of 2024 [17]. In Southeast Asia, a study estimated that 2.9 million dengue cases and >5000 deaths occurred each year in the 2000s, with an annual economic burden of US $950 million [18].

Given the complex dynamics of dengue transmission, which involve vectors, humans, and the environment [19,20], effective dengue prevention requires a combination of vaccines and vector control measures [21]. Due to the lack of widely available dengue vaccines, vector control remains the primary strategy for dengue prevention. However, community-based approaches to vector control rely heavily on the knowledge and behaviors of individuals within the community [22]. Likewise, upon the availability of a dengue vaccine, its uptake would also hinge upon the public’s awareness and understanding to facilitate its swift adoption among populations.

Over the past 75 years, dengue vaccine development has proven difficult, with only live attenuated virus vaccines achieving licensure or phase 3 status [23]. The first dengue vaccine (CYD-TDV) was licensed in 2015, but after its launch, updated data showed an increased risk of severe outcomes in vaccine recipients without a previous dengue infection compared to their unvaccinated counterparts [24]. The WHO soon revised its recommendation that CYD-TDV should only be used in previously infected individuals [25]. In the Philippines, where this vaccine was introduced into the national immunization program, there was a controversy regarding this vaccine’s safety [26]. This controversy led to increased hesitancy toward not only dengue vaccines but also COVID-19 vaccines and routine immunization in the country [25-27]. Recently, the approval of a 2-dose vaccine named TAK-003 in several countries has marked a significant advancement in dengue disease prevention, where it could be used regardless of previous exposure [28,29]. In 2024, the WHO fulfilled its advisory role by issuing a position paper on dengue vaccines tailored for large-scale vaccination initiatives [30]. Within this directive, the WHO recommends the administration of TAK-003, particularly targeting children aged 6 to 16 years, especially in regions with high dengue transmission rates [30,31]. This recommendation gains further importance against the backdrop of escalating dengue cases reported in endemic areas, underscoring the urgent need for additional preventive measures.

Consequently, evidence-based guidance is needed to inform the development of vaccination education strategies involving DOLs, particularly given the scientific complexity of dengue and past controversies surrounding dengue vaccines. While SMIs have been involved in infectious disease prevention previously, the specific role of medically qualified DOLs in dengue prevention and how they differ from SMIs lacking medical backgrounds remains unexplored.

This study aims to examine the role and practice of DOLs in influencing dengue awareness and prevention on social media platforms. In addition, we investigated DOLs’ preferred modes of collaboration with other stakeholders in the health sector on dengue prevention.

We used a qualitative study approach to address the study objectives. Specifically, we conducted semistructured interviews with purposively selected DOLs in 8 countries in Latin America (Argentina, Brazil, and Colombia) and Southeast Asia (Indonesia, Malaysia, the Philippines, Singapore, and Thailand), where dengue is endemic.

We purposively recruited DOLs who were qualified health care providers and have been actively disseminating information on infectious disease prevention (including dengue) and vaccination online. Specific inclusion criteria are listed in Textbox 1. Web-based research was conducted by the research team to identify eligible DOLs in each country. On the basis of the inclusion and exclusion criteria, we selected and compiled a list of potential study participants who met the inclusion criteria in each country. The research team contacted potential participants either using their contact information available online or via their social media accounts to obtain initial consent to participate in our study.

In each country, interviews were conducted by female facilitators who had bachelor’s degrees in communication or health-related majors and extensive experience in qualitative research. To minimize interviewer bias and ensure consistency in interview delivery, all interviews were moderated by the same facilitator in each country, and the DOLs did not have established relationships or previous knowledge of the interviewers. A topic guide was used to facilitate the interviews (Multimedia Appendix 1). In Singapore, Malaysia, and the Philippines, interviews were conducted in English. In Indonesia, Thailand, Brazil, Argentina, and Colombia, interviews were conducted either in English or the local languages, depending on participants’ preferences. The topic guide was translated into local languages and reviewed by the research team before the interviews to ensure translation accuracy. A briefing session was conducted with all the facilitators to ensure they were thoroughly familiar with the objectives and methods of the study as well as the interview process and the questions in the topic guide.

The DOLs were initially contacted via email or direct messages through their social media platforms to seek their consent for participation in this study. Interviews were conducted either online (using video or audio calls) or in person, based on the participants’ preferences. Each interview lasted approximately 60 minutes and was audio recorded, with field notes taken concurrently. The interviews commenced with participant introductions and proceeded to cover three main areas: (1) the DOLs’ journey and engagement strategies with their followers; (2) their experiences and current practices in disseminating health information, particularly on dengue and other infectious disease prevention; and (3) the strategies and approaches they used or preferred for collaborating with various stakeholders in the health sector. In this study, the health sector is defined to encompass a broad range of stakeholders involved in or influencing the delivery of health care services or products, such as health care providers, public health agencies, the pharmaceutical industry, nongovernmental organizations (NGOs), and government regulatory agencies [32,33]. All audio-recorded interviews were transcribed verbatim. Transcriptions of interviews conducted in languages other than English were translated into English. None of the recruited DOLs withdrew from the study. Transcripts were not returned to the DOLs for their review or correction.

We used a thematic analysis approach to analyze the data generated from the interviews [34]. Adopting an interpretivist lens, we focused on participants’ experiences, perceptions, and understanding of the discussed topics [35]. After data familiarization, 2 researchers coded the first 5 transcripts inductively and independently. They compared the codes regularly to ensure intercoder reliability and identified emerging themes. Disagreement was resolved through discussion and consultation with a third researcher who could provide neutral views on the analyzed data. Once a coding frame was developed and agreed upon, it was applied to the remaining transcripts to ensure consistency. The codes were refined and grouped into subthemes and main themes iteratively. The coding frame was finalized after analyzing all transcripts. The 2 researchers reviewed the themes to ensure alignment with the research questions and refined them as necessary. The analysis was conducted using Microsoft Excel. The findings were not returned to the DOLs for their review or feedback. The study methods and results were reported following the COREQ (Consolidated Criteria for Reporting Qualitative Research) checklist (Multimedia Appendix 2) [36].

This study received an exemption from the Pearl Institutional Review Board (reference number 2023-0424). Informed consent was obtained through a participant’s dated signature. For web-based interviews, the consent form was emailed to the participant before the interview. Participants provided their electronic signatures and returned the form via email. Data collected from the interviews were deidentified to ensure confidentiality, and access to these digital files was restricted to members of the research team. Participants received an honorarium based on the fair market value in each country as governed by the country’s pharmaceutical regulation and fair market value.

A total of 94 DOLs were identified to be eligible and approached, of which 37 (39%) gave their consent to participate in this study. As shown in Table 2, among these 37 DOLs interviewed, 24 (65%) were from Southeast Asia and 13 (35%) from Latin America, with a nearly equal distribution of female (n=17, 46%) and male (n=20, 54%) participants. Most DOLs were pediatricians (n=17, 46%) and had <20 years of professional experience (n=19, 51%). Most participants had been active online as DOLs for 3 to 5 years (n=16, 43%) or 5 to 10 years (n=11, 30%). The most commonly used social media platforms included TikTok (n=32, 86%), Instagram (n=29, 78%), Facebook (n=19, 51%), and YouTube (n=16, 43%). Across all platforms, most (27/37, 73%) participants had follower counts ranging from 14,000 to 300,000, with 6 (16%) participants having >600,000 followers.

DOLs primarily targeted a diverse audience through their content creation efforts, aiming to educate and engage individuals across various demographics. Of the 37 DOLs, many reported that their primary audience was the general public (n=23, 62%) and predominantly women (n=20, 54%). Most (n=32, 86%) DOLs mentioned that their followers were aged between 18 and 40 years. Some (n=10, 27%) DOLs, particularly those from Latin American countries, also indicated that they were followed by health care providers. As a result, the content created by the DOLs was often tailored to resonate with both laypersons and health care professionals, seeking to bridge gaps in public understanding while also facilitating knowledge exchange among health professionals.

As shown in Multimedia Appendix 3, the five emerging themes were organized into three sections to address the study objectives: (1) the increasing influence of DOLs in infectious disease prevention, (2) current practices of DOLs contributing to dengue prevention, and (3) exploring ways of collaboration to strengthen dengue prevention. The corresponding quotes supporting each theme are also presented in Multimedia Appendix 3.

The DOLs participating in this study acknowledged that the rise of social media and the increasing presence of health care providers in the digital space had changed how individuals sought and accessed health information. Currently, the DOLs contribute to the prevention of infectious diseases on online platforms through 3 primary pathways: raising public awareness, dispelling misconceptions, and serving as role models.

Many (16/37, 43%) DOLs perceived their primary role as raising public awareness about infectious diseases and their prevention. Leveraging the power of social media, DOLs aimed to educate the public on crucial health topics, including the recognition of common signs and symptoms of diseases and the appropriate timing for seeking medical care. Recognizing that building awareness was a gradual process, DOLs often began with simple, relatable content to encourage informed behaviors. For instance, they used notable cases, including those of prominent individuals with diseases such as dengue, to underscore the severity of certain conditions and advocate for preventive measures, such as vaccination. However, DOLs acknowledged that while online information dissemination could enhance knowledge, translating this knowledge into actionable behaviors was not guaranteed.

Many (17/37, 46%) DOLs mentioned that they actively addressed misconceptions surrounding infectious disease prevention, especially regarding vaccines. They tackled community concerns, such as fears of vaccines causing autism or other adverse events, by producing content that provided explanations and clarifications on these issues. Through their efforts, they aimed to educate the public and alleviate concerns. In addition, these DOLs emphasized that while vaccines are crucial for disease prevention, they are just one aspect of a comprehensive strategy that should also include everyday preventive activities. Furthermore, they addressed misunderstandings regarding vaccine efficacy and corrected the misconception that vaccination provided absolute immunity, as illustrated in the following quote:

Furthermore, some (8/37, 22%) DOLs mentioned serving as role models for infectious disease prevention. Through their own health-promoting behaviors, they influenced their audiences to adopt similar practices. For example, DOLs shared personal practices, such as placing sand in plant dishes to prevent mosquito breeding, thereby educating and motivating their followers to take similar preventive actions. In addition, some (3/37, 8%) DOLs shared their experiences with receiving influenza or COVID-19 vaccinations to encourage vaccination uptake among their audience.

In this qualitative study, we found that online influencers, including qualified health care professionals (DOLs), have become an important avenue for public health education, particularly concerning the prevention of infectious diseases, such as dengue. Although traditional vector control methods remain essential and are actively endorsed by DOLs, the public’s attention can wane due to message fatigue. Both the public and DOLs are interested in new methods for dengue prevention, such as vaccines and new vector control technologies, such as Wolbachia. DOLs recognize the need to increase awareness and deliver education about dengue vaccines. They are aware of their role in debunking misconceptions and controversies about dengue vaccines in the digital space as a means to tackle vaccine hesitancy.

Our findings align with several well-established communication theories, offering a conceptual foundation for understanding their role in health promotion and communication. First, our findings align with the diffusion of innovations theory, which describes how new ideas and health information spread through communication channels before reaching the public [37]. In the case of DOLs, they act as intermediaries who disseminate evidence-based messages to their online audiences. Second, our findings align with the two-step flow theory, which suggests that media messages are not directly absorbed by the public but instead filtered through opinion leaders who reinterpret and disseminate information [38]. Previous research examining the role of SMIs in public health communication during the COVID-19 pandemic found that SMIs served as information mediators, translating and personalizing public health messages for their audiences while shaping social norms around pandemic behaviors [9]. This study reinforces the model by demonstrating how DOLs, akin to SMIs, adapted official health messages to enhance accessibility and engagement [9]. By effectively translating complex health information, DOLs facilitated the adoption of preventive behaviors, such as dengue vaccination and vector control measures, among their online audiences.

While DOLs and SMIs share overlapping roles in health communication, there are notable distinctions that can impact the weight and trustworthiness of their messages. First, misinterpretations by SMIs can arise due to their lack of formal medical training, as medical information can be complex and confusing without proper expertise [39,40]. Instead of delivering content based on rigorous evidence, SMIs often focus on fostering engagement with their audience that is more emotion driven with less emphasis on factual accuracy. This can sometimes lead to the inadvertent spread of misinformation, contributing to antivaccination movements and vaccine hesitancy, particularly during the COVID-19 pandemic [41-43]. This highlights the importance of medical training in accurately interpreting and conveying health information. DOLs, as medically trained professionals, use information from credible and authoritative sources to create their content, ensuring the validation of information and guiding their audience toward reliable sources [44]. There is substantial evidence supporting the positive impact of SMIs on health promotion, but the additional medical expertise of DOLs enhances the reliability of the health information they share.

Second, the motivations driving content creation can differ among influencers. Many SMIs leverage their influence for monetization through advertisements and brand endorsements, a common practice in the marketing and advertising industries, which can sometimes influence the type of content they produce [45-47]. In contrast, DOLs, who are also part of the broader SMI community, are typically bound by strict medical and ethical codes to adhere to unbiased, evidence-based practices in their posts. Our research supports this, showing that DOLs often avoid direct product endorsements, instead focusing on promoting scientifically backed health knowledge and behaviors. This approach helps build trust with their audience and enhances their credibility as sources of online health information.

Third, the ability of DOLs to navigate scientific and medical literature makes them valuable partners in health promotion activities. This is particularly true for complex diseases, such as dengue, where both the public and DOLs show a keen interest in novel approaches, such as vaccination and new vector control technologies. These approaches underscore the necessity for reliable and up-to-date information, which often can only be accessed through collaborations with ministries, recommending bodies, and vaccine manufacturers. Although collaborations within the health sector for dengue prevention remain limited, our study demonstrated that DOLs are receptive to engaging with diverse entities, provided these partnerships adhere to ethical standards and are backed by credible scientific evidence. These collaborations enable DOLs to align on best practices and public health priorities while staying informed about the latest technologies and developments in dengue prevention and treatment.

Expanding on the aforementioned information, we also noted differences in collaborative approaches between SMIs and DOLs. For instance, when government agencies engaged SMIs in campaigns for promoting influenza vaccines or raising awareness about COVID-19, SMIs were given fact-checked information to share directly or incorporate into their content [9,48]. Although this approach ensures the accuracy of shared information, studies argue that it does not fully leverage an influencer’s unique content creation abilities or reflect their persona, potentially undermining the impact of SMIs in health campaigns [49]. In addition, SMIs were sometimes not required to respond to comments by campaign sponsors, as the sponsors provided sample responses or guidelines for SMIs to engage with their audience and respond to technical questions [48,50]. In contrast, medically trained DOLs often enjoy more creative freedom. On the basis of our study, DOLs are frequently tasked with creating technical-oriented content. Furthermore, they are encouraged to actively counter misinformation on online platforms, engage in online forums to address queries, and monitor online discussions and sentiments about vaccines, thereby contributing to shaping a well-informed public perception of dengue vaccines [51,52].

More importantly, DOLs’ online activities can complement offline dengue prevention efforts. They can participate in dengue awareness and education campaigns led by NGOs or government health authorities, thereby improving reach and engagement among young, active online users. This can augment traditional dengue prevention campaigns, which often face challenges of limited reach and sustainability due to resource constraints for physical campaign activities, particularly in low- and middle-income countries [53].

Furthermore, as social media emerges as a primary source of health information, including vaccine-related content [54-56], the role of DOLs becomes increasingly crucial in addressing vaccine hesitancy by combating online misinformation and disinformation [51,57]. This is particularly relevant for raising awareness about dengue vaccines and the potential introduction of new dengue vaccines in the near future. DOLs can be leveraged to support vaccine advocacy efforts and tackle vaccine hesitancy through collaboration with various stakeholders, including national or regional health authorities, international organizations, pharmaceutical companies, and NGOs.

Leveraging their online influence and credibility, DOLs are invaluable in raising awareness about dengue preventive measures. They can play a crucial role in vaccine educational efforts by disseminating accurate information about vaccines and addressing hesitancy, especially with the introduction of a new dengue vaccine. To optimize the effectiveness of DOLs in dengue prevention strategies, we propose the following recommendations for best practices focusing on 2 key areas: content creation and collaboration (Figure 1).

First, to enhance the effectiveness of health communication, it is crucial to identify key aspects essential for understanding dengue and its prevention. Dengue is a complex disease with a wide spectrum of clinical presentations and intricate transmission dynamics involving vectors, humans, and the environment [19,20,58]. In addition, the nuanced considerations in the use of dengue vaccines, including differing recommendations based on previous exposure status and the anticipated effects of the vaccines, necessitate clear and accessible communication to prevent confusion and address vaccine hesitancy among the public [59-61]. To optimize the effectiveness of content created by DOLs, it is essential to tailor it to specific social media platforms and ensure that it resonates with the audience. Simplifying complex medical concepts and scientific evidence without resorting to jargon is vital for ensuring accessibility to a wide audience. Furthermore, citing references and sources can bolster the credibility of the content and educate the audience about reliable health information resources.

Second, collaborations between DOLs and other health sector stakeholders should focus on the ethical promotion of health behaviors or education rather than endorsing specific brands or products. This is particularly relevant when DOLs engage with pharmaceutical companies. Obtaining information about novel vaccines, such as those for dengue, can be challenging, and accessing such information may require direct engagement with pharmaceutical companies. To facilitate DOLs in upholding ethical and professional standards, collaborations between DOLs and pharmaceutical companies could involve training sessions to ensure accurate and informed posting of vaccine-related information. It is important to present scientific evidence that supports partnership efforts, emphasizing an evidence-based approach. In addition, given that dengue prevention is often a government-initiated priority, partnering with government agencies for public education initiatives and aligning with their strategies can be beneficial for effectively disseminating information about dengue prevention and vaccination. DOLs should consciously avoid endorsing or naming specific products in their content but focus on promoting prevention measures and raising awareness about dengue. However, such collaboration with government authorities is sometimes challenged by the lengthy process of obtaining approvals. Streamlining the approval process would make these collaborations more efficient and help avoid unnecessary delays.

To our knowledge, this is the first qualitative study to explore the role and practices of DOLs with medical credentials in the domain of dengue prevention. Our findings support the engagement of DOLs as an innovative channel in public health promotion that could significantly enhance dengue prevention initiatives. Moreover, the recruitment of DOLs from dengue-endemic regions ensures the representativeness of our study participants in discussing dengue prevention strategies. The inclusion of participants from a wide range of countries helped enrich the data with opinions from different perspectives. Finally, data saturation was achieved, with no new codes or themes emerging after the analysis of 12 transcripts.

Our study has several limitations. First, we focused exclusively on DOLs specializing in communicable diseases and vaccination, which may limit the generalizability of our findings to other health topics. Future research exploring DOLs’ roles across different disease contexts could provide a broader understanding of their impact. In addition, selection bias may be present, as we recruited DOLs with substantial social media followings due to their wider reach and potential for public health collaboration. While this approach captured insights from those with the greatest audience influence, it may have excluded perspectives from DOLs with smaller platforms, who might use different engagement strategies. Second, as with all qualitative research, our findings are subject to interpretation. To ensure rigor, we used a structured topic guide, conducted interviews using experienced qualitative researchers in each country, held facilitator briefing sessions to align methodological approaches, and engaged multiple researchers in data analysis to reduce bias [62]. Third, while thematic saturation was not a predetermined sampling criterion, we observed inductive data saturation, as no new themes emerged after analyzing 12 interviews [63]. Fourth, member checking was not conducted due to practical constraints. Re-engaging health care professionals across 8 countries would have imposed a significant logistical burden, likely leading to low response rates and selection bias. In addition, multilingual translations could have introduced inconsistencies, while the additional time and financial resources required for postanalysis engagement made member checking unfeasible within the study’s scope. Finally, our findings indicate limited engagement of DOLs in dengue prevention collaborations with other health sector stakeholders. This may reflect insufficient governmental initiatives for dengue prevention and control, as reported by the DOLs in our study and previous research [64,65]. Future studies incorporating perspectives from government agencies responsible for communicable disease prevention are needed to address this knowledge gap.

As a credible health information source, DOLs can be instrumental in raising awareness about dengue preventive measures and introducing new dengue prevention strategies, including dengue vaccines, particularly to the digitally engaged population that often seeks health information online. Recognizing the multifaceted nature of dengue prevention, collaborative endeavors involving DOLs should prioritize the ethical promotion of health knowledge and behaviors over product endorsement, which is particularly relevant when collaborating with pharmaceutical companies. By leveraging their credibility and reach, DOLs stand poised to catalyze transformative efforts in dengue prevention, heralding a new era of collective action and informed public health discourse.