Evaluating the Effectiveness of Internet-Based Communication for Public Health: Systematic Review

Background Communicating strategically is a key issue for health organizations. Over the past decade, health care communication via social media and websites has generated a great deal of studies examining different realities of communication strategies. However, when it comes to systematic reviews, there is fragmentary evidence on this type of communication. Objective The aim of this systematic review was to summarize the evidence on web institutional health communication for public health authorities to evaluate possible aim-specific key points based on these existing studies. Methods Guided by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement, we conducted a comprehensive review across 2 electronic databases (PubMed and Web of Science) from January 1, 2011, to October 7, 2021, searching for studies investigating institutional health communication. In total, 2 independent researchers (AN and SS) reviewed the articles for inclusion, and the assessment of methodological quality was based on the Kmet appraisal checklist. Results A total of 78 articles were selected. Most studies (35/78, 45%) targeted health promotion and disease prevention, followed by crisis communication (24/78, 31%), general health (13/78, 17%), and misinformation correction and health promotion (6/78, 8%). Engagement and message framing were the most analyzed aspects. Few studies (14/78, 18%) focused on campaign effectiveness. Only 23% (18/78) of the studies had an experimental design. The Kmet evaluation was used to distinguish studies presenting a solid structure from lacking studies. In particular, considering the 0.75-point threshold, 36% (28/78) of the studies were excluded. Studies above this threshold were used to identify a series of aim-specific and medium-specific suggestions as the communication strategies used differed greatly. Conclusions Overall, the findings suggest that no single strategy works best in the case of web-based health care communication. The extreme variability of outcomes and the lack of a unitary measure for assessing the end points of a specific campaign or study lead us to reconsider the tools we use to evaluate the efficacy of web-based health communication.

The majority of posts were implicitly targeting youth, with only 5.3% of the posts explicitly mentioning them. The most interactive implicitly targeted posts consistently resulted in higher numbers of interactions compared to the most interactive explicitly targeted posts, regardless of social media platform.
Many of the PHE accounts used the same post multiple times on different days. This may be seen as either an advantage or a disadvantage; Given the high number of youth on Instagram, PHEs may want to consider targeting youth on this site; Given the high concentration of youth on YouTube and the amount of time spent on this platform, PHEs may want to consider using YouTube in future health promotion campaigns in order to target the audiences 18 and younger. It was suspected that participants were aware of the benefits of the staying at home and thus formed highly favorable attitudes toward stay ing at home behavior. Results also further revealed that perceived norms and self-efficacy did not fully account for the association between interpersonal communication and behavioural intentions. • Government institutions such as the White House, CDC, and HHSGov were found to be highly authoritative and trustworthy sources • Entities with the highest betweenness centrality are mostly experts in infectious disease, several actors involved in politics also have high betweenness centrality Public health organizations can benefit by understanding the kinds of content that is transmitted through specific social media platforms and by identifying key participants who are authoritative, popular, and connected to disparate communities in order to efficiently communicate with the public. • Making use of the expertise and infrastructure of existing organizations saves critical time in responding to public health threats • Referring the public to expert groups that individuals can contact directly, expands the ways in which consumers can access information • Cross-referencing official guidance across organizations extends the reach of the content and demonstrates a consensus from trusted public health organizations • Establishing a means early on to collect detailed data on public inquiries allows organizations to measure their impact and adapt messaging in response to areas of public concern or confusion 0.46 Jang et al.

KR
Examine how credibility of information from PHOs is associated with the use of particular communication channels among a wide array of alternatives.  (51) 1 year (January 2016 -December 2016) Engagement • Findings showed that the public liked and shared the most in the pre-outbreak phase, and engaged much less in the outbreak messages than they did in the pre-outbreak phase • The public liked posts the most that encouraged self-efficacy Pre-outbreak messages on social media should include all the necessary information to update and educate the public about the risk of the potential crises, while providing reassurance and self-efficacy. The information function was the most prominent function, followed by the action or community functions. Beliefs regarding susceptibility, severity, and benefits were the most frequently covered health beliefs. Tweets that served the information or action functions were more likely to be retweeted, while tweets that served the action and community functions were more likely to be liked. Tweets that provided susceptibility information resulted in the most public engagement in terms of the number of retweets and likes.
Public health agencies should continue to use Twitter to disseminate information, promote action, and build communities. They need to improve their strategies for designing social media messages about the benefits of disease prevention behaviors and audiences'self-efficacy.

Engagement
The number of account followers, betweenness centrality, close-ness centrality, positive emotion, and tentativeness were all significantly associated with retweeting activity.
• Influential people shold be identified and targeted because their messages are more likely to be disseminated.
• Develop reliable messages about diagnosis, symptoms, and treatments with emotionally positive tones in an effort to capture the intended audiences' attention, associate an emotional state with coping behaviors, and promote social support and help people with health problems cope better • Health promotion organizations frequently provided statistics and facts and used a more serious tone, while lifestyle brands were positive and relatable • Positive emotion-inducing strategies were associated with more interactions on Facebook and Instagram and using an optimistic tone was associated with more interactions on Facebook • Posts classified as "relatable" were negatively associated with Facebook interactions but positively associated with Instagram interactions • Videos and body image content were statistically significantly positively associated with Facebook interactions, but not associated with Instagram interactions Health promotion organizations should try to build relationships with their users in a similar fashion as the lifestyle brands do. Conduct a content analysis of health communications posted on diabetes-related Facebook pages and explore the role of crowdsourcing (direct solicitation of user input) and use of external links and videos.

Facebook
Common-Sense Model of Illness Self-Regulation Content analysis Posts (500) 3-49 days Engagement • Imagery was the strongest predictor of both liking a health communication and sharing it with others but it also reduced the number of comments when paired with causal information • The use ofimagery attenuated or reversed the positive relationships of diabetes consequence information, control information, nega-tive affect, positive identity, and social support with user engagement • Messages with expressions of negative affect were shared less frequently relative to mes-sages without negative affect • External links were associated with lower engagement •Imagery should be carefully employed since it appears to be a powerful tool for attracting attention and briefly engaging users (i.e., increasing likes) as well as increasing message transmission (i.e., increasing shares).However, use of images with information about illness consequences and control or with messages conveying negative affect could mute responses.

Engagement
The moderator choose from a list of standardized responses; there was no attempt to engage in the conversation or stimulate discussion; allowed time for other posters to correct misinformation and then endorsed the corrections. User-generated content did not resolve uncertainty around some aspects of chlamydia testing: this maintained conversations by generating disagreement and encouraged sharing personal experience.
Moderation for online health promotion interventions: (1) unengaged and professional oversight to provide a safe space for discussion and to maintain information quality and (2)

Engagement
• Personal experience tweets were associated with more retweets in comparison with factual information tweets. tweets from individual senders wereassociated with fewer retweets in comparison to those from organiza-tional senders • Tweets with factual information and from organizational senders were significantly more likely to produce shares. Each of these factors was found to have an independent causal effect onmessage sharing behavior In the social media contexts, the relative importance of having clear informational content sent from organizations will be much greater for generating highly viewed and highly shared cancer prevention messages 0.93 Zhang et al.

US Disease prevention
Examine content variables, including threat and efficacy, and user variables, including processing style and image promotional consideration, to investigate the combined influence in driving SNS users' intention to share fear appeal messages. Three of the videos managed to raise sufficient attention to be shared further by a newspaper online portal. One video (the "dramatic" one) went viral. Viewers need to find the content particularly interesting or useful to them personally. Enhancing factors: well-known presenter, a "doomsday" topic, the presence of a controversy and an ongoing public debate.
Adjust the language and presentation used to be of more appeal to popular culture. Linking promotional materials to other popular topics could prove to be a successful strategy to achieve this.

US
Describe the contents and followers of the Twitter profile @CDC_AMD and to assess if attaching photos or videos to tweets posted by @CDC_AMD would increase retweet frequency.
Twitter n/a Observational Tweets (768) 18 months (5 May 2015 -16 November 2016) Engagement Attaching photos or videos to original @CDC_AMD tweets increases the number of retweets by 37%. Content topics did not explain or modify this association.
Attaching visual cues to tweets will increase their retweet frequency, and this practice may enhance Twitter users' engagement with health communication messages promoted by medical and public health professionals. • In terms of information design, credibility is better presented in the West than in the East, whereas users' needs are better presented in the East than in the West.
• In terms of multimedia design, demonstrations and humanity are better presented in the West than in the East, and the segmentation of demonstrations is valued by both the East and the West • In terms of interface design, the West presents a better appearance than the East, and methodology is valued by both the East and the West • General terms should replace the professional term • Simplified textbased content should be used • Advertising space, wich may increase users' cognition load and mislead patients' treatment decisions, must be reduced • Hi-Tec multimedia design, which may decrease the amount of explanatory text and increase the cognitive load, must be reduced 0.63 Kim et al.

2020
US Explore the use of Instagram by the Centers for Disease Control and Prevention. Instagram n/a Content analysis Posts (1,545) n/a Engagement • The most frequent type of photo was text mainly about calls for actions, detailed information were usually listed in post texts •The mean engagement and the mean comment sentiments of text categorized photos were not relatively high • Photos with more and bigger human faces had lower level of engagement and an higher level of comment sentiment, happiness and neutral expressed on the faces in photos were negatively associated with engagement.
• The variances of RGB, the variances of saturation and value, share of warm colors, contrast, and RGB contrast, were negatively correlated with engagement The message design should be different depending on whether they aim to increase the number of likes and comments or they aim to induce more positive response from public. Information quality had significant associations with all outcome variables: user satisfaction, intention to reuse the site, and perceived benefits of site use in health settings. Service quality had a significant association with user satisfaction, and its impact on perceived benefits occurred indirectly through user satisfaction and intention.
It is important to build trusted relationships with site usersand appropriately respond to their demands.
Both the quality of the information provided on a health information site and the quality of service available on the site play significant roles in increasing users' perceived benefits.

US, UK
Identify the key factors influencing US and UK citizens' trust and intention to act on advice found on health websites and to understand the role of patient experiences.
Website n/a Observational Adults (1123) n/a Message framing Trust was found to have a significant direct effect on intention to act, and of the trust factors, only credibility and impartiality had a significant direct effect on trust. The impact of personal experiences on trust was mediated through information corroboration.
Impartiality continues to remain a key predictor of trust in health websites as well as the extent to which users consider information sources to be credible. The presence of personal experiences information can have a positive influence on trust provided that users corroborate the information through additional sources. Three of the videos managed to raise sufficient attention to be shared further by a newspaper online portal. One video (the "dramatic" one) went viral. Viewers need to find the content particularly interesting or useful to them personally. Enhancing factors: well-known presenter, a "doomsday" topic, the presence of a controversy and an ongoing public debate.

0.81
Adjust the language and presentation used to be of more appeal to popular culture. Linking promotional materials to other popular topics could prove to be a successful strategy to achieve this.

US
Describe the contents and followers of the Twitter profile @CDC_AMD and to assess if attaching photos or videos to tweets posted by @CDC_AMD would increase retweet frequency.
Twitter n/a Observational Tweets (768) 18 months (5 May 2015 -16 November 2016) Engagement Attaching photos or videos to original @CDC_AMD tweets increases the number of retweets by 37%. Content topics did not explain or modify this association.
Attaching visual cues to tweets will increase their retweet frequency, and this practice may enhance Twitter users' engagement with health communication messages promoted by medical and public health professionals. • In terms of information design, credibility is better presented in the West than in the East, whereas users' needs are better presented in the East than in the West.
• In terms of multimedia design, demonstrations and humanity are better presented in the West than in the East, and the segmentation of demonstrations is valued by both the East and the West • In terms of interface design, the West presents a better appearance than the East, and methodology is valued by both the East and the West • General terms should replace the professional term • Simplified textbased content should be used • Advertising space, wich may increase users' cognition load and mislead patients' treatment decisions, must be reduced • Hi-Tec multimedia design, which may decrease the amount of explanatory text and increase the cognitive load, must be reduced Information quality had significant associations with all outcome variables: user satisfaction, intention to reuse the site, and perceived benefits of site use in health settings. Service quality had a significant association with user satisfaction, and its impact on perceived benefits occurred indirectly through user satisfaction and intention.
It is important to build trusted relationships with site usersand appropriately respond to their demands.
Both the quality of the information provided on a health information site and the quality of service available on the site play significant roles in increasing users' perceived benefits.

US, UK
Identify the key factors influencing US and UK citizens' trust and intention to act on advice found on health websites and to understand the role of patient experiences.
Website n/a Observational Adults (1123) n/a Message framing Trust was found to have a significant direct effect on intention to act, and of the trust factors, only credibility and impartiality had a significant direct effect on trust. The impact of personal experiences on trust was mediated through information corroboration.
Impartiality continues to remain a key predictor of trust in health websites as well as the extent to which users consider information sources to be credible. The presence of personal experiences information can have a positive influence on trust provided that users corroborate the information through additional sources. • The average reliability and satisfaction was significantly higher for subjects that had read the experimental condition correction post rather than the subject that had read the traditional correction post • Even the pro-vaccination group prefers to receive full information that addresses emotions and concerns and expresses less satisfaction with a response that does not address those aspects

0.81
The findings indicate that it is very important for organizations to correct misinformation transparently while addressing the emotional aspect both for the pro-vaccination and the hesitant group.