The effect of a short, animated story-based video on COVID-19 vaccine hesitancy: A study protocol for an online randomized controlled trial.

Introduction: Exposure to a high volume of vaccine misinformation on social media can have a negative effect on vaccine confidence and rates. To counteract misinformation, we designed a collage of three short, animated story-based (SAS) videos to convey scientifically informed and accessible information about COVID-19 vaccine applicable to a social media context. Methods and analysis: We will conduct an online randomized controlled trial primarily to: (1) determine the effectiveness of SAS videos in improving COVID-19 vaccine knowledge; (2) evaluate the effectiveness of SAS videos in increasing behavioral intent for COVID-19 vaccination; and (3) quantify people's interest in watching SAS videos about the COVID-19 vaccine. We also aim to identify barriers and facilitators to COIVD-19 vaccinations that have been shown to minimize vaccine hesitancy between vaccinated and unvaccinated populations. Using a web-based recruitment platform, a total of 10,000 adults from the United States will be recruited and randomly assigned to (1) a SAS video collage arm, (2) an attention placebo control video arm, or (3) no intervention arm (1:1:1). Furthermore, we will measure behavioral intent to obtain information on vaccination regarding COVID-19. At the end of the trial, participants randomized to arm 2 and arm 3 will be given the option of watching one of the intervention videos voluntarily to assess participant engagement with SAS videos. Finally, we will assess individual factors associated with vaccine hesitancy - hope, optimism, COVID-19 perceived risks and benefits, self-efficacy, perceived social norms, and trust - and compare vaccinated and unvaccinated participants across the three arms. Discussions: Evidence-based information from official channels can be complex and inaccessible to the general public, whereas false information on social media is frequently shared in brief postings, images, or videos that can easily reach the general public, thereby rapidly disseminating (mis-)information. To avoid the spread of misinformation, social media may be used to deliver evidence-based and emotionally compelling information in a readily accessible format in order to pre-empt misinformation. Our findings may help inform future SAS efforts addressing COVID-19 and other important public health challenges. Ethics and dissemination: The study was approved by the Heidelberg University Hospital's Ethics Committee (S-163/2022). The trial was registered with German Clinical Trials Register (www.drks.de) on 5 January 2022: number DRKS00027938. Findings of the study will be published in peer-reviewed scientific publications and possibly presented at scientific conferences.

Effects of side-effect risk framing strategies on COVID-19 vaccine intentions: a randomized controlled trial.

Background: Fear over side-effects is one of the main drivers of COVID-19 vaccine hesitancy. A large literature in the behavioral and communication sciences finds that how risks are framed and presented to individuals affects their judgments of its severity. However, it remains unknown whether such framing changes can affect COVID-19 vaccine behavior and be deployed as policy solutions to reduce hesitancy. Methods: We conducted a pre-registered randomized controlled trial among 8998 participants in the United States and the United Kingdom to examine the effects of different ways of framing and presenting vaccine side-effects on individuals' willingness to get vaccinated and their perceptions of vaccine safety. Results: Adding a descriptive risk label ('very low risk') next to the numerical side-effect and providing a comparison to motor-vehicle mortality increased participants' willingness to take the COVID-19 vaccine by 3.0 percentage points (p=0.003) and 2.4 percentage points (p=0.049), respectively. These effects were independent and additive and combining both framing strategies increased willingness to receive the vaccine by 6.1 percentage points (p<0.001). Mechanistically, we find evidence that these framing effects operate by increasing individuals' perceptions of how safe the vaccine is. Conclusions: Low-cost side-effect framing strategies can meaningfully affect vaccine intentions at a population level. Funding: Heidelberg Institute of Global Health. Clinical trial number: German Clinical Trials Registry (#DRKS00025551).

Vaccination is one of the main strategies for controlling the COVID-19 pandemic. But vaccination rates have slowed and are below target levels in countries like the United States and the United Kingdom. While there are many causes of vaccine hesitancy, several studies have found that fear of side effects is the one of the most important. Although COVID-19 vaccine side-effects are rare, how the media presents these risks may amplify concerns. Addressing public concerns over vaccine side effects is key to improving the uptake of vaccines and booster doses, which has been even lower than primary vaccine series uptake. Studies show that how risk is presented affects people's risk perceptions and behavior. To learn more about how COVID-19 vaccine risk framing affects risk perception, Sudharsanan et al. enrolled 8,998 people from the United States and the United Kingdom in an online randomized controlled trial. Participants received information about a hypothetical new COVID-19 vaccine, including its side effect rate, and reported their perception of safety and whether they would take the vaccine. The experiments showed that adding the label "very low risk" when describing vaccine side effect rates increased the number of people who said they would take the vaccine by three percentage points. Comparing the risks of the hypothetical vaccine to the much higher chances of motor vehicle deaths increased an individual's willingness to take the vaccine by 2.4 percentage points. Combining both framing strategies increased people's desire to get vaccinated by 6.1 percentage points. Deploying these two strategies in vaccine risk communications may help increase primary and booster vaccinations against COVID-19. A next step would be to measure both vaccination intentions and vaccination rates to confirm these strategies.

Participant engagement with a short, wordless, animated video on COVID-19 prevention: a multi-site randomized trial.

COVID-19 misinformation has spread rapidly across social media. To counter misinformation, we designed a short, wordless and animated video (called the CoVideo) to deliver scientifically informed and emotionally compelling information about preventive COVID-19 behaviours. After 15 163 online participants were recruited from Germany, Mexico, Spain, the UK and the USA, we offered participants in the attention placebo control (APC) and do-nothing arms the option to watch the CoVideo (without additional compensation) as post-trial access to treatment. The objective of our study was to evaluate participant engagement by quantifying (i) the proportion of participants opting to watch the CoVideo and (ii) the duration of time spent watching the CoVideo. We quantified the CoVideo opt-in and view time by experimental arm, age, gender, educational status, country of residence and COVID-19 prevention knowledge. Overall engagement with the CoVideo was high: 72% of the participants [CI: 71.1%; 73.0%] opted to watch the CoVideo with an average view time of 138.9 out of 144.0 s [CI: 138.4; 139.4], with no statistically significant differences by arm. Older participants (35-59 years) and participants with higher COVID-19 prevention knowledge had higher view times than their counterparts. Spanish participants had the highest opt-in percentage whereas Germans exhibited the shortest view times of the five countries. Short, wordless and animated storytelling videos, optimized for 'viral spread' on social media, can enhance global engagement with COVID-19 prevention messages by transcending cultural, language and literary barriers.

The effect of framing and communicating COVID-19 vaccine side-effect risks on vaccine intentions for adults in the UK and the USA: A structured summary of a study protocol for a randomized controlled trial.

OBJECTIVES: Vaccine hesitancy is a major hurdle for stopping the COVID-19 pandemic. Recently, fear of vaccine side effects created widespread concern and paused global vaccination efforts. Many studies find that how medical risks are framed and communicated can influence individuals' perceptions and behavior, yet there is little evidence on how the communication of COVID-19 vaccine side-effect risks influences vaccine intentions. The primary objective of our study is to evaluate how the framing of vaccine-side effect risks impacts individuals' vaccine intentions and perceptions of vaccine safety. The study will assess the impact of 3 dimensions of side-effect framing: 1. Qualitative risk labels: Determine whether attaching a qualitative risk label (e.g. adding "very low risk" next to the actual numerical risk) impacts individuals' willingness to take a vaccine and their perceptions of its safety. 2. Comparison groups: Determine how framing side-effect risks in comparison to other causes of mortality (COVID-19 mortality and motor vehicle mortality) impacts individuals' willingness to take a vaccine and their perceptions of its safety. 3. How the comparison risks are presented: Determine whether comparisons to other causes of mortality are presented on an absolute or relative scale impacts individuals' willingness to take a vaccine and their perceptions of its safety. Secondarily, we will also randomize a subset of individuals to receive the "status-quo" framing, where the vaccine side-effect risks are presented like how they were presented in the media. We will then compare vaccine intentions and perceptions of vaccine safety between the status-quo and the pooled intervention group samples to provide some insight into how "harmful" the status-quo framing was. Ultimately, we believe that our results will provide the some of the first experimental evidence on how the communication of COVID-19 vaccine risks may impact the public's willingness to be vaccinated and can inform future efforts to increase vaccination rates. TRIAL DESIGN: Our study is an online-based randomized controlled trial designed to evaluate the effect of different vaccine side-effect framings on COVID-19 vaccine intentions and perceived safety for a hypothetical COVID-19 vaccine. Using a factorial design, we will experimentally assess the impact of 3 risk framing strategies, varying whether the risk is presented: (1) with a qualitative label, (2) whether the risk is presented with a comparison risk, and (3) for comparison cases, whether the comparison is in absolute or relative terms. We will also randomize a portion of respondents to a status quo framing where the side effect risk mimics the media's communication in early April 2021. PARTICIPANTS: This will be an online study setting. We will use Prolific to recruit participants and host our study on the Gorilla platform. To be eligible, participants must be 18 years old or over (male, female, or other), have current residence in the US or UK, and be able to speak English. Participants will be excluded from the study if they do not meet our inclusion criteria. INTERVENTION AND COMPARATOR: Our study content will consist of five pages presented to individuals online. Page 1 will explain the purpose of the study and contain the consent information. Page 2 will contain basic sociodemographic questions, including participants' age, sex, and schooling level. Page 3 will set up the experiment by telling individuals that we will describe a hypothetical new COVID-19 vaccine and that we would like to know how likely they would be to take the vaccine and how safe they think the vaccine is. On this page, we will also encourage individuals to respond truthfully and remind them that their answers are confidential and cannot be linked back to any personal identifying information. Page 4 will be the main experimental slide, where we will present individuals with information on the vaccine, varying how the vaccination risk is communicated based on which experimental framing arm they are randomized to. We will factorially randomize across the following factors in the following order (separately by country). First, we will determine whether individuals are randomized to the status quo framing, or the intervention framings (1500 respondents to the status quo, and 4500 to the intervention). Among those randomized to the intervention framing, we will randomize (equal allocation) whether the side effect is presented without a comparison, with a comparison to COVID-19 mortality, or with a comparison to motor vehicle mortality. We will then factorially randomize (equal allocation) whether the risk is presented with a qualitative risk label or not (e.g. "very low risk"). To ensure that the factors are independent of one another, we will do this by randomizing individuals to the risk labels within strata of the comparison group factor. Lastly, among those randomized to the comparison group, we will factorially randomize whether the risk is presented as an absolute or relative comparison. As previously, we will ensure independence by doing this randomization within strata of comparison group*risk labelling. This entire design is visualized in the full protocol. The experimental text for each arm is: Arm 1: With regards to side effects, so far 8 individuals have developed potentially life-threatening blood clots. This is among the approximately 7 million adults that have received the vaccine so far. Arm 2: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. Arm 3: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). Arm 4: Text for USA participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. As a reference, 170 out of every 100,000 unvaccinated Americans died of COVID-19 based on data from the past year. Text for UK participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. As a reference, 108 out of every 100,000 unvaccinated individuals in the UK died of COVID-19 based on data from the past year. Arm 5: Text for USA participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. As a reference, this is 1/170th of the risk of COVID-19 mortality among unvaccinated Americans based on data from the past year. Text for UK participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. As a reference, this is 1/108th of the risk of COVID-19 mortality among unvaccinated individuals in the UK based on data from the past year. Arm 6: Text for USA participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). As a reference, 170 out of every 100,000 unvaccinated Americans died of COVID-19 based on data from the past year. Text for UK participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). As a reference, 108 out of every 100,000 unvaccinated individuals in the UK died of COVID-19 based on data from the past year. Arm 7: Text for USA participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). As a reference, this is 1/170th of the risk of COVID-19 mortality among unvaccinated Americans based on data from the past year. Text for UK participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). As a reference, this is 1/108th of the risk of COVID-19 mortality among unvaccinated individuals in the UK based on data from the past year. Arm 8: Text for USA participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. As a reference, 12 out of every 100,000 Americans died in a motor vehicle accident based on data from the past year. Text for UK participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. As a reference, 2.6 out of every 100,000 individuals in the UK died in a motor vehicle accident based on data from the past year. Arm 9: Text for USA participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. As a reference, this is 1/12th of the risk of dying in a motor vehicle accident based on data from the past year. Text for UK participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots. As a reference, this is almost 1/4th of the risk of dying in a motor vehicle accident based on data from the past year. Arm 10: Text for USA participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). As a reference, 12 out of every 100,000 Americans died in a motor vehicle accident based on data from the past year. Text for UK participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). As a reference, 2.6 out of every 100,000 individuals in the UK died in a motor vehicle accident based on data from the past year. Arm 11: Text for USA participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). As a reference, this is 1/12th of the risk of dying in a motor vehicle accident based on data from the past year. Text for UK participants: With regards to side effects, 1 out of 100,000 vaccinated individuals may develop serious blood clots (very low risk). As a reference, this is nearly 1/4th of the risk of dying in a motor vehicle accidentbased on data from the past year. The risk information will be presented on a single page along with the two main outcome questions. Lastly, for individuals that reported that they are unlikely or unsure about whether they would take the vaccine, the final page will ask them their reason (question based on a recently published study of COVID-19 vaccine hesitancy). MAIN OUTCOMES: Our primary outcome is individuals' willingness to take the hypothetical COVID-19 vaccine. We will measure this outcome by asking, "How likely would you be to take this vaccine?" allowing individuals to choose from a four-point Likert response of "Unlikely, Unsure leaning towards unlikely, Unsure leaning towards likely, Very likely." This outcome variable, including the categories and phrasing, is based on a recently published study on COVID-19 vaccine hesitancy conducted by researchers with the Vaccine Hesitance Project at the London School of Hygiene and Tropical Medicine. Our secondary outcome is individuals' perceived safety of the vaccine. We will assess this outcome by asking individuals, "How safe do you feel this vaccine is?" allowing them to choose answers ranging from 1-10 where 1 is extremely unsafe, and 10 is extremely safe. Both outcomes will be measured at the time of the questionnaire. Participants can take up to 45 min to complete the questions but will not be able to go back and change their responses after submitting their questionnaire. RANDOMIZATION: Using a web-based randomization algorithm, Gorilla will randomly allocate participants to each of the experimental arms. Gorilla allows for two randomization options - independent randomization of each individual based on a probability draw and balanced randomization, which randomizes without replacement such that among groups of respondents a fixed proportion will end up in each experimental arm. We will use the "balanced randomization" option to ensure that our experimental arms are balanced. Participants will be randomized based on the allocations described above. BLINDING: Because Prolific handles the interaction between the study investigators and participants, the participants will be completely anonymous to the study investigators. The outcome measures will be self-reported and submitted anonymously. All persons in the study team will be blinded to the group allocation. NUMBERS TO BE RANDOMIZED: We will randomize 6000 participants per country for a total sample of 12000 individuals. TRIAL STATUS: The protocol version number is 1.0 and the date is July 14, 2021. Recruitment is expected to begin on 26 July 2021 and end by August 10, 2021. TRIAL REGISTRATION: The study and its outcomes were registered at the German Clinical Trials Register ( www.drks.de ) on July 12th, 2021: # DRKS00025551 . FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Full_Protocol_20Jul2021) In the interest of expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

The Effect of a Wordless, Animated, Social Media Video Intervention on COVID-19 Prevention: Online Randomized Controlled Trial.

BACKGROUND: Innovative approaches to the dissemination of evidence-based COVID-19 health messages are urgently needed to counter social media misinformation about the pandemic. To this end, we designed a short, wordless, animated global health communication video (the CoVideo), which was rapidly distributed through social media channels to an international audience. OBJECTIVE: The objectives of this study were to (1) establish the CoVideo's effectiveness in improving COVID-19 prevention knowledge, and (2) establish the CoVideo's effectiveness in increasing behavioral intent toward COVID-19 prevention. METHODS: In May and June 2020, we enrolled 15,163 online participants from the United States, Mexico, the United Kingdom, Germany, and Spain. We randomized participants to (1) the CoVideo arm, (2) an attention placebo control (APC) arm, and (3) a do-nothing arm, and presented 18 knowledge questions about preventive COVID-19 behaviors, which was our first primary endpoint. To measure behavioral intent, our second primary endpoint, we randomized participants in each arm to five list experiments. RESULTS: Globally, the video intervention was viewed 1.2 million times within the first 10 days of its release and more than 15 million times within the first 4 months. Knowledge in the CoVideo arm was significantly higher (mean 16.95, 95% CI 16.91-16.99) than in the do-nothing (mean 16.86, 95% CI 16.83-16.90; P<.001) arm. We observed high baseline levels of behavioral intent to perform many of the preventive behaviors featured in the video intervention. We were only able to detect a statistically significant impact of the CoVideo on one of the five preventive behaviors. CONCLUSIONS: Despite high baseline levels, the intervention was effective at boosting knowledge of COVID-19 prevention. We were only able to capture a measurable change in behavioral intent toward one of the five COVID-19 preventive behaviors examined in this study. The global reach of this health communication intervention and the high voluntary engagement of trial participants highlight several innovative features that could inform the design and dissemination of public health messages. Short, wordless, animated videos, distributed by health authorities via social media, may be an effective pathway for rapid global health communication during health crises. TRIAL REGISTRATION: German Clinical Trials Register DRKS00021582; https://tinyurl.com/6r4zkbbn. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1186/s13063-020-04942-7.