This study examines temporal trends, geographic distribution, and demographic correlates of anti-vaccine beliefs on Twitter, 2009–2015. A total of 549,972 tweets were downloaded and coded for the presence of anti-vaccine beliefs through a machine learning algorithm. Tweets with self-disclosed geographic information were resolved and United States Census data were collected for corresponding areas at the micropolitan/metropolitan level. Trends in number of anti-vaccine tweets were examined at the national and state levels over time. A least absolute shrinkage and selection operator regression model was used to determine census variables that were correlated with anti-vaccination tweet volume. Fifty percent of our sample of 549,972 tweets collected between 2009 and 2015 contained anti-vaccine beliefs. Anti-vaccine tweet volume increased after vaccine-related news coverage. California, Connecticut, Massachusetts, New York, and Pennsylvania had anti-vaccination tweet volume that deviated from the national average. Demographic characteristics explained 67% of variance in geographic clustering of anti-vaccine tweets, which were associated with a larger population and higher concentrations of women who recently gave birth, households with high income levels, men aged 40 to 44, and men with minimal college education. Monitoring anti-vaccination beliefs on Twitter can uncover vaccine-related concerns and misconceptions, serve as an indicator of shifts in public opinion, and equip pediatricians to refute anti-vaccine arguments. Real-time interventions are needed to counter anti-vaccination beliefs online. Identifying clusters of anti-vaccination beliefs can help public health professionals disseminate targeted/tailored interventions to geographic locations and demographic sectors of the population.

Standardized collection of social determinants of health in the Electronic Health Record is an importantfirst step in promoting more effective PCC.

Risk perceptions, an important determinant of positive behavioral change, are often conceptualized as an additive or multiplicative index of two concepts: susceptibility to and severity of a health risk. Susceptibility is the possibility of experiencing a health risk, whereas severity is its seriousness or harmfulness. This article challenged the current theorization of risk perceptions. To demonstrate the differential perceptions of susceptibility and severity, two self-report studies (N = 70, each) and one reaction time study (N = 476) provided data on 50 health conditions that varied on several risk characteristics (e.g., prevalence, personal experience). Results showed that susceptibility and severity were two distinct, inversely related concepts. Perceived susceptibility and severity varied by risk characteristics, mainly prevalence (i.e., how common a health risk was perceived to be). Self-report data showed that a progressive increase in perceptions of a health risk prevalence rates was associated with an increase in susceptibility and a decrease in severity (and vice versa). Reaction-time data mirrored this pattern and showed these differential perceptions of susceptibility and severity were highly accessible, as evident by fast reaction times. Several individual differences (e.g., optimism) emerged as significant predictors of risk perceptions and their accessibility. Theoretical and practical implications are discussed.

ObjectiveUnder US law, tobacco product marketing may claim lower exposure to chemicals, or lower risk of health harms, only if these claims do not mislead the public. We sought to examine the impact of such marketing claims about potential modified risk tobacco products (MRTPs).MethodsParticipants were national samples of 4797 adults and 969 adolescent US smokers and non-smokers. We provided information about a potential MRTP (heated tobacco product, electronic cigarette or snus). Experiment 1 stated that the MRTP was as harmful as cigarettes or less harmful (lower risk claim). Experiment 2 stated that the MRTP exposed users to a similar quantity of harmful chemicals as cigarettes or to fewer chemicals (lower exposure claim).ResultsClaiming lower risk led to lower perceived quantity of chemicals and lower perceived risk among adults and adolescents (all p<0.05, Experiment 1). Among adults, this claim led to higher susceptibility to using the MRTP (p<0.05). Claiming lower exposure led to lower perceived chemical quantity and lower perceived risk (all p<0.05), but had no effect on use susceptibility (Experiment 2). Participants thought that snus exposed users to more chemicals and was less safe to use than heated tobacco products or electronic cigarette MRTPs (Experiments 1 and 2).DiscussionRisk and exposure claims acted similarly on MRTP beliefs. Lower exposure claims misled the public to perceive lower perceived risk even though no lower risk claim was explicitly made, which is impermissible under US law.