Vaccine Special Issue: The Role of Internet Use in Vaccination Decisions

Volume 30, Issue 25, Pages 3723-3818 (28 May 2012)

Special Issue: The Role of Internet Use in Vaccination Decisions
Edited by Cornelia Betsch and Katharina Sachse

Section 1. Web 2.0 – What it is and how it may affect vaccination decisions
Opportunities and challenges of Web 2.0 for vaccination decisions
Original Research Article
Pages 3727-3733
Cornelia Betsch, Noel T. Brewer, Pauline Brocard, Patrick Davies, Wolfgang Gaissmaier, Niels Haase, Julie Leask, Frank Renkewitz, Britta Renner, Valerie F. Reyna, Constanze Rossmann, Katharina Sachse, Alexander Schachinger, Michael Siegrist, Marybelle Stryk

A growing number of people use the Internet to obtain health information, including information about vaccines. Websites that allow and promote interaction among users are an increasingly popular source of health information. Users of such so-called Web 2.0 applications (e.g. social media), while still in the minority, represent a growing proportion of online communicators, including vocal and active anti-vaccination groups as well as public health communicators. In this paper, the authors: define Web 2.0 and examine how it may influence vaccination decisions; discuss how anti-vaccination movements use Web 2.0 as well as the challenges Web 2.0 holds for public health communicators; describe the types of information used in these different settings; introduce the theoretical background that can be used to design effective vaccination communication in a Web 2.0 environment; make recommendations for practice and pose open questions for future research. The authors conclude that, as a result of the Internet and Web 2.0, private and public concerns surrounding vaccinations have the potential to virally spread across the globe in a quick, efficient and vivid manner. Web 2.0 may influence vaccination decisions by delivering information that alters the perceived personal risk of vaccine-preventable diseases or vaccination side-effects. It appears useful for public health officials to put effort into increasing the effectiveness of existing communication by implementing interactive, customized communication. A key step to providing successful public health communication is to identify those who are particularly vulnerable to finding and using unreliable and misleading information. Thus, it appears worthwhile that public health websites strive to be easy to find, easy to use, attractive in its presentation and readily provide the information, support and advice that the searcher is looking for. This holds especially when less knowledgeable individuals are in need of reliable information about vaccination risks and benefits.

The defining characteristics of Web 2.0 and their potential influence in the online vaccination debate
Original Research Article
Pages 3734-3740
Holly O. Witteman, Brian J. Zikmund-Fisher

The emergence of Web 2.0 has led to more and more Web-based resources demonstrating three defining characteristics: user participation, openness and network effects. This paper discusses these characteristics in the context of the online vaccination debate, explores how they structurally alter the way people might interact with vaccination information online, and describes ways in which such characteristics support particular tendencies in human decision making processes. Specifically, user participation supports the influence of narratives and personal accounts, openness shapes expectations for greater levels of detail and movement toward models of informed decision making, and network effects demonstrate the social nature of decision making, the influence of like-minded others and thus, the pitfalls of polarization in the online vaccination debate. Web 2.0 means that concerns about vaccination information online must expand beyond simply the possibility that people might access information of varying quality to incorporate a more comprehensive understanding of how people use current Web functionality, how such usage influences expectations about information sources and decision making processes, and the implications for communication strategies about vaccination.

Section 2. Surfing the web – processing the obtained information
Sorting through search results: A content analysis of HPV vaccine information online
Original Research Article
Pages 3741-3746
Kelly Madden, Xiaoli Nan, Rowena Briones, Leah Waks

Surveys have shown that many people now turn to the Internet for health information when making health-related decisions. This study systematically analyzed the HPV vaccine information returned by online search engines. HPV is the most common sexually transmitted disease and is the leading cause of cervical cancers.

We conducted a content analysis of 89 top search results from Google, Yahoo, Bing, and The websites were analyzed with respect to source, tone, information related to specific content analyzed through the lens of the Health Belief Model, and in terms of two content themes (i.e., conspiracy theories and civil liberties). The relations among these aspects of the websites were also explored.

Most websites were published by nonprofit or academic sources (34.8%) and governmental agencies (27.4%) and were neutral in tone (57.3%), neither promoting nor opposing the HPV vaccine. Overall, the websites presented suboptimal or inaccurate information related to the five behavioral predictors stipulated in the Health Belief Model. Questions related to civil liberties were present on some websites.

Health professionals designing online communication with the intent of increasing HPV vaccine uptake should take care to include information about the risks of HPV, including susceptibility and severity. Additionally, websites should include information about the benefits of the vaccine (i.e., effective against HPV), low side effects as a barrier that can be overcome, and ways in which to receive the vaccine to raise individual self-efficacy.

Do the media provide transparent health information? A cross-cultural comparison of public information about the HPV vaccine
Original Research Article
Pages 3747-3756
Nicolai Bodemer, Stephanie M. Müller, Yasmina Okan, Rocio Garcia-Retamero, Angela Neumeyer-Gromen

The media is a powerful tool for informing the public about health treatments. In particular, the Internet has gained importance as a widely valued source for health information for parents and adolescents. Nonetheless, traditional sources, such as newspapers, continue to report on health innovations. But do websites and newspaper reports provide balanced information? We performed a systematic media analysis to evaluate and compare media coverage of the human papillomavirus (HPV) vaccine on websites and in newspapers in Germany and Spain. We assessed to what extent the media provide complete (pros and cons), transparent (absolute instead of relative numbers), and correct information about the epidemiology and etiology of cervical cancer as well as the effectiveness and costs of the HPV vaccine. As a basis for comparison, a facts box containing current scientific evidence about cervical cancer and the HPV vaccine was developed. The media analysis included 61 websites and 141 newspaper articles in Germany, and 41 websites and 293 newspaper articles in Spain. Results show that 57% of German websites and 43% of German newspaper reports communicated correct estimates of epidemiological data, whereas in Spain 39% of the websites and 20% of the newspaper did so. While two thirds of Spanish websites explicitly mentioned causes of cervical cancer as well as spontaneous recovery, German websites communicated etiological information less frequently. Findings reveal that correct estimates about the vaccine’s effectiveness were mentioned in 10% of German websites and 6% of German newspaper reports; none of the Spanish newspaper reports and 2% of Spanish websites reported effectiveness correctly. Only German websites (13%) explicitly referred to scientific uncertainty regarding the vaccine’s evaluation. We conclude that the media lack balanced reporting on the dimensions completeness, transparency, and correctness. We propose standards for more balanced reporting on websites and in newspapers.

Parents’ Internet use for information about HPV vaccine
Original Research Article
Pages 3757-3762
Annie-Laurie McRee, Paul L. Reiter, Noel T. Brewer

The Internet is an increasingly common source of health-related information. We sought to examine associations between parents’ Internet information-seeking and their knowledge, attitudes and beliefs about human papillomavirus (HPV) vaccine.

We interviewed parents within a year after approval of HPV vaccine for females and males. Participants were North Carolina parents with daughters ages 10–18 surveyed by telephone in Fall 2007 (n = 773); and a national sample of parents with sons ages 11–17 surveyed online in Fall 2010 (n = 115). We used multivariate regression to examine associations of past and intended Internet seeking for HPV vaccine information with knowledge and health belief model-related constructs.

Among parents of daughters, having heard of HPV vaccine through the Internet (8%) was associated with higher HPV knowledge, perceived likelihood of HPV, and vaccination willingness, and with receiving a doctor’s recommendation. It was also associated with lower perceived vaccine harms, uncertainty, and anticipated regret. Parents of sons who heard of HPV vaccine through the Internet (10%) perceived greater barriers to vaccination than parents who learned about HPV vaccine for males through other sources. Intended future Internet information-seeking among parents of daughters (69%) was more likely if they perceived a lower likelihood that their daughters would get HPV if they were vaccinated (all p < .05).

Our findings suggest a positive influence of accessing information on the Internet about HPV vaccine. It was associated with higher knowledge and mostly positive parental attitudes and beliefs.

Vaccine-critical videos on YouTube and their impact on medical students’ attitudes about seasonal influenza immunization: A pre and post study
Original Research Article
Pages 3763-3770
Pierre Robichaud, Steven Hawken, Leslie Beard, Dante Morra, George Tomlinson, Kumanan Wilson, Jennifer Keelan

YouTube is a video-sharing platform that is increasingly utilized to share and disseminate health-related information about immunization. Using a pre–post survey methodology, we compared the impact of two of the most popular YouTube videos discussing seasonal influenza vaccine, both vaccine-critical, on the attitudes towards immunizing of first year medical students attending a Canadian medical school. Forty-one medical students were randomized to view either a scientifically styled, seemingly “evidence-based”, vaccine-critical video or a video using anecdotal stories of harms and highly sensationalized imagery. In the pre-intervention survey, medical students frequently used YouTube for all-purposes, while 42% used YouTube for health-related purposes and 12% used YouTube to search for health information. While medical students were generally supportive of immunizing, there was suboptimal uptake of annual influenza vaccine reported, and a subset of our study population expressed vaccine-critical attitudes and behaviors with respect to seasonal influenza. Overall there was no significant difference in pre to post attitudes towards influenza immunization nor were there any differences when comparing the two different vaccine-critical videos. The results of our study are reassuring in that they suggest that medical students are relatively resistant to the predominately inaccurate, vaccine-critical messaging on YouTube, even when the message is framed as scientific reasoning. Further empirical work is required to test the popular notion that information disseminated through social media platforms influences health-related attitudes and behaviors. However, our study suggests that there is an opportunity for public health to leverage YouTube to communicate accurate and credible information regarding influenza to medical students and others.

Measuring people’s knowledge about vaccination: Developing a one-dimensional scale
Original Research Article
Pages 3771-3777
Alexandra Zingg, Michael Siegrist

We propose a new scale to measure people’s general knowledge about vaccinations. The scale’s psychometric properties and its relationship with people’s willingness to vaccinate were examined in two studies. In Study 1, a representative sample of the German- and French-speaking populations in Switzerland (N = 1123) responded to a mail survey. In Study 2, members of an online panel answered the same questions (N = 233). The results of both studies suggest that people differ considerably in their ability to correctly answer questions related to vaccinations. Mokken scale analyses and a test-retest analysis showed that nine items form a one-dimensional scale with good psychometric properties. In both studies, a substantial correlation between knowledge and willingness to vaccinate was observed. The scale proposed in this study is well suited for research examining group differences. In a time when new media such as the Internet is highly accessible to most people, misconceptions can easily be spread. A good knowledge scale is important for measuring possible knowledge changes.

Section 3. Online communication strategies – advocacy in a minefield
Anti-vaccine activists, Web 2.0, and the postmodern paradigm – An overview of tactics and tropes used online by the anti-vaccination movement
Original Research Article
Pages 3778-3789
Anna Kata

Websites opposing vaccination are prevalent on the Internet. Web 2.0, defined by interaction and user-generated content, has become ubiquitous. Furthermore, a new postmodern paradigm of healthcare has emerged, where power has shifted from doctors to patients, the legitimacy of science is questioned, and expertise is redefined. Together this has created an environment where anti-vaccine activists are able to effectively spread their messages. Evidence shows that individuals turn to the Internet for vaccination advice, and suggests such sources can impact vaccination decisions – therefore it is likely that anti-vaccine websites can influence whether people vaccinate themselves or their children. This overview examines the types of rhetoric individuals may encounter online in order to better understand why the anti-vaccination movement can be convincing, despite lacking scientific support for their claims. Tactics and tropes commonly used to argue against vaccination are described. This includes actions such as skewing science, shifting hypotheses, censoring dissent, and attacking critics; also discussed are frequently made claims such as not being “anti-vaccine” but “pro-safe vaccines”, that vaccines are toxic or unnatural, and more. Recognizing disingenuous claims made by the anti-vaccination movement is essential in order to critically evaluate the information and misinformation encountered online.

Risk perception and communication in vaccination decisions: A fuzzy-trace theory approach
Original Research Article
Pages 3790-3797
Valerie F. Reyna

The tenets of fuzzy-trace theory, along with prior research on risk perception and risk communication, are used to develop a process model of vaccination decisions in the era of Web 2.0. The theory characterizes these decisions in terms of background knowledge, dual mental representations (verbatim and gist), retrieval of values, and application of values to representations in context. Lack of knowledge interferes with the ability to extract the essential meaning, or gist, of vaccination messages. Prevention decisions have, by definition, a status quo option of “feeling okay.” Psychological evidence from other prevention decisions, such as cancer screening, indicates that many people initially mentally represent their decision options in terms of simple, categorical gist: a choice between (a) a feeling-okay option (e.g., the unvaccinated status quo) versus (b) taking up preventive behavior that can have two potential categorical outcomes: feeling okay or not feeling okay. Hence, applying the same theoretical rules as used to explain framing effects and the Allais paradox, the decision to get a flu shot, for example, boils down to feeling okay (not sick) versus feeling okay (not sick) or not feeling okay (sick, side effects, or death). Because feeling okay is superior to not feeling okay (a retrieved value), this impoverished gist supports choosing not to have the flu vaccine. Anti-vaccination sources provide more coherent accounts of the gist of vaccination than official sources, filling a need to understand rare adverse outcomes.

A public-professional web-bridge for vaccines and vaccination: User concerns about vaccine safety
Original Research Article
Pages 3798-3805
Alberto L. García-Basteiro, María-José Álvarez-Pasquín, Guillermo Mena, Anna Llupià, Marta Aldea, Victor-Guillermo Sequera, Sergi Sanz, Jose Tuells, José-Antonio Navarro-Alonso, Javier de Arísteguí, José-María Bayas

Abstract (), a website founded by the Spanish Association of Vaccinology offers a personalized service called Ask the Expert, which answers any questions posed by the public or health professionals about vaccines and vaccination. The aim of this study was to analyze the factors associated with questions on vaccination safety and determine the characteristics of questioners and the type of question asked during the period 2008–2010. A total of 1341 questions were finally included in the analysis. Of those, 30% were related to vaccine safety. Questions about pregnant women had 5.01 higher odds of asking about safety (95% CI 2.82–8.93) than people not belonging to any risk group. Older questioners (>50 years) were less likely to ask about vaccine safety compared to younger questioners (OR: 0.44, 95% CI 0.25–0.76). Questions made after vaccination or related to influenza (including H1N1) or travel vaccines were also associated with a higher likelihood of asking about vaccine safety. These results identify risk groups (pregnant women), population groups (older people) and some vaccines (travel and influenza vaccines, including H1N1) where greater efforts to provide improved, more-tailored vaccine information in general and on the Internet are required.

Lessons from an online debate about measles–mumps–rubella (MMR) immunization
Original Research Article
Pages 3806-3812
Michelle S. Nicholson, Julie Leask

To provide strategies for immunization advocates on how best to participate in online discussion forums about immunization.

Content and thematic analysis of an online discussion forum held following the national screening of a documentary about the measles-mumps-rubella (MMR) vaccine and autism scare. A subsample of branches containing more than 20 posts was analysed. Each distinct message (a “post”) was coded for the author’s manifest position on immunization, author type, topic, and evidence presented or sought.

From 103 distinct branches there were 1193 posts sent over a 3½ h period. We selected the 13 longest branches containing 466 posts from 166 individuals. One third of these individuals were explicitly critical of MMR immunization and one third sought information. The remainder were ambivalent but seeking no information (5%), supportive (14%), or unstated (15%). Among five author categories, only 4% identified themselves as health professionals. Topics included alleged adverse effects of immunization (35%); autism spectrum disorders treatment and causes (31%); vaccine ingredients (12%); a conspiracy (9%); immunization policies (8%); and measles, mumps or rubella (4%). Scientific concepts of evidence failed to compete with lay concepts and personal anecdotes prevailed.

Health professionals and other advocates of immunization should engage in similar types of post-broadcast online discussion forums in a planned and strategic manner that accounts for the decision processes of lay people. This involves expanding and diversifying the support base of people contributing to the forum; setting the agenda; introducing messages known to influence behaviour; not overselling vaccination; and avoiding personal attacks.

Toward interactive, Internet-based decision aid for vaccination decisions: Better information alone is not enough
Original Research Article
Pages 3813-3818
Terry Connolly, Jochen Reb

Vaccination decisions, as in choosing whether or not to immunize one’s small child against specific diseases, are both psychologically and computationally complex. The psychological complexities have been extensively studied, often in the context of shaping convincing or persuasive messages that will encourage parents to vaccinate their children. The computational complexity of the decision has been less noted. However, even if the parent has access to neutral, accurate, credible information on vaccination risks and benefits, he or she can easily be overwhelmed by the task of combining this information into a well-reasoned decision. We argue here that the Internet, in addition to its potential as an information source, could provide useful assistance to parents in integrating factual information with their own values and preferences – that is, in providing real decision aid as well as information aid. We sketch one approach for accomplishing this by means of a hierarchy of interactive decision aids ranging from simple advice to full-scale decision analysis.