Sentiment, Contents, and Retweets: A Study of Two Vaccine-Related Twitter Datasets.

INTRODUCTION: Social media platforms are important channels through which health education about the utility and safety of vaccination is conducted. OBJECTIVE: To investigate if tweets with different sentiments toward vaccination and different contents attract different levels of Twitter users' engagement (retweets). METHODS: A stratified random sample (N = 1425) of 142,891 #vaccine tweets (February 4, 2010, to November 10, 2016) was manually coded. All 201 tweets with 100 or more retweets from 194,259 #vaccineswork tweets (January 1, 2014, to April 30, 2015) were manually coded. Regression models were applied to identify factors associated with retweet frequency. RESULTS: Among #vaccine tweets, provaccine tweets (adjusted prevalence ratio = 1.5836, 95% confidence interval = 1.2130-2.0713, p < 0.001) and antivaccine tweets (adjusted prevalence ratio = 4.1280, 95% confidence interval = 3.1183-5.4901, p < 0.001) had more retweets than neutral tweets. No significant differences occurred in retweet frequency for content categories among antivaccine tweets. Among 411 links in provaccine tweets, Twitter (53; 12.9%), content curator Trap.it (14; 3.4%), and the Centers for Disease Control and Prevention (8; 1.9%) ranked as the top 3 domains. Among 325 links in antivaccine tweets, social media links were common: Twitter (44; 14.9%), YouTube (25; 8.4%), and Facebook (10; 3.4%). Among highly retweeted #vaccineswork tweets, the most common theme was childhood vaccinations (40%; 81/201); 21% mentioned global vaccination improvement/efforts (42/201); 29% mentioned vaccines can prevent outbreaks and deaths (58/201). CONCLUSION: Engaging social media key opinion leaders to facilitate health education about vaccination in their tweets may allow reaching a wider audience online.

Contents, Followers, and Retweets of the Centers for Disease Control and Prevention's Office of Advanced Molecular Detection (@CDC_AMD) Twitter Profile: Cross-Sectional Study.

BACKGROUND: The Office of Advanced Molecular Detection (OAMD), Centers for Disease Control and Prevention (CDC), manages a Twitter profile (@CDC_AMD). To our knowledge, no prior study has analyzed a CDC Twitter handle's entire contents and all followers. OBJECTIVE: This study aimed to 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. METHODS: Data of @CDC_AMD were retrieved on November 21, 2016. All followers (N=809) were manually categorized. All tweets (N=768) were manually coded for contents and whether photos or videos were attached. Retweet count for each tweet was recorded. Negative binomial regression models were applied to both the original and the retweet corpora. RESULTS: Among the 809 followers, 26.0% (210/809) were individual health professionals, 11.6% (94/809) nongovernmental organizations, 3.3% (27/809) government agencies' accounts, 3.3% (27/809) accounts of media organizations and journalists, and 0.9% (7/809) academic journals, with 54.9% (444/809) categorized as miscellaneous. A total of 46.9% (360/768) of @CDC_AMD's tweets referred to the Office's website and their current research; 17.6% (135/768) referred to their scientists' publications. Moreover, 80% (69/86) of tweets retweeted by @CDC_AMD fell into the miscellaneous category. In addition, 43.4% (333/768) of the tweets contained photos or videos, whereas the remaining 56.6% (435/768) did not. Attaching photos or videos to original @CDC_AMD tweets increases the number of retweets by 37% (probability ratio=1.37, 95% CI 1.13-1.67, P=.002). Content topics did not explain or modify this association. CONCLUSIONS: This study confirms CDC health communicators' experience that original tweets created by @CDC_AMD Twitter profile sharing images or videos (or their links) received more retweets. The current policy of attaching images to tweets should be encouraged.

Fluoride-related YouTube videos: A cross-sectional study of video contents by upload sources.

Purpose: The aim of this study was to describe characteristics of the most widely viewed fluoride-related videos on the video sharing website, YouTube, and to compare the content of videos uploaded from different sources.Methods: Using a cross-sectional design, a total of 100 fluoride-related, English language videos were manually coded and statistically analyzed.Results: A majority of videos were consumer-generated. Videos that were consumer-generated had the most views of any source (9,737,845 views; 69.32%). Compared to consumer-generated videos, videos uploaded by a professional source were 15.52 times as likely to mention fluoridated toothpaste (Odds ratio, OR=15.52, 95% CI, 1.92, 125.35), 5.04 times as likely to mention the need for training of health personnel (OR=5.04, 95% CI, 1.15, 22.02), 9.69 times as likely to mention the benefits of fluoride on teeth (OR=9.69; 95% CI, 2.01, 46.81), 3.52 times as likely to mention that too much fluoride is negative (OR=3.52, 95% CI, 1.06, 11.73), and 3.44 times as likely to mention the dangers of fluoride use in children 1-5 years old (OR=3.44, 95% CI, 1.05, 11.23).Conclusion: Widely-viewed fluoride-related information on YouTube has an anti-fluoride sentiment, focusing more on the danger of fluoride rather than its benefits.