Vaccine hesitancy: evidence from an adverse events following immunization database, and the role of cognitive biases.

BACKGROUND: Vaccine hesitancy has been a growing challenge for public health in recent decades. Among factors contributing to vaccine hesitancy, concerns regarding vaccine safety and Adverse Events (AEs) play the leading role. Moreover, cognitive biases are critical in connecting such concerns to vaccine hesitancy behaviors, but their role has not been comprehensively studied. In this study, our first objective is to address concerns regarding vaccine AEs to increase vaccine acceptance. Our second objective is to identify the potential cognitive biases connecting vaccine hesitancy concerns to vaccine-hesitant behaviors and identify the mechanism they get triggered in the vaccine decision-making process. METHODS: First, to mitigate concerns regarding AEs, we quantitatively analyzed the U.S. Vaccine Adverse Event Reporting System (VAERS) from 2011 to 2018 and provided evidence regarding the non-severity of the AEs that can be used as a communicable summary to increase vaccine acceptance. Second, we focused on the vaccination decision-making process. We reviewed cognitive biases and vaccine hesitancy literature to identify the most potential cognitive biases that affect vaccine hesitancy and categorized them adopting the Precaution Adoption Process Model (PAPM). RESULTS: Our results show that the top frequent AEs are expected mild reactions like injection site erythema (4.29%), pyrexia (3.66%), and injection site swelling (3.21%). 94.5% of the reports are not serious and the average population-based serious reporting rate over the 8 years was 25.3 reports per 1 million population. We also identified 15 potential cognitive biases that might affect people's vaccination decision-making and nudge them toward vaccine hesitancy. We categorized these biases based on the factors that trigger them and discussed how they contribute to vaccine hesitancy. CONCLUSIONS: This paper provided an evidence-based communicable summary of VAERS. As the most trusted sources of vaccine information, health practitioners can use this summary to provide evidence-based vaccine information to vaccine decision-makers (patients/parents) and mitigate concerns over vaccine safety and AEs. In addition, we identified 15 potential cognitive biases that might affect the vaccination decision-making process and nudge people toward vaccine hesitancy. Any plan, intervention, and message to increase vaccination uptake should be modified to decrease the effect of these potential cognitive biases.

Sources affecting knowledge and behavior responses to the Zika virus in US households with current pregnancy, intended pregnancy and a high probability of unintended pregnancy.

Background: This study examined the influences of information sources on Zika-relevant knowledge and behaviors in US households containing members who are pregnant, intend to become pregnant, or have a higher probability of unintended pregnancy in Zika-affected regions (i.e. respondents who are younger, are black, have less education, are unmarried, and reside in the southern USA). Methods: Over 32 000 US adults completed a survey measuring Zika-relevant knowledge and behaviors along with information sources (e.g. discussing Zika with practitioners), general media usage (e.g. TV) and demographic information over 30 weeks. Results: Respondents in the group with (versus without) either pregnancy or intended pregnancy were more likely to use all information sources, which in turn created differences in knowledge and behavior responses. To gauge information sources in US-South respondents with a high probability of having a household member with unintended pregnancy based on demographics, younger, less-educated, unmarried, black respondents had fewer Zika discussion with practitioners than another group. Conclusions: Efforts to increase Zika-related knowledge and protective behaviors should target households with members who are pregnant or intending to become pregnant via practitioners, family and friends. Additional efforts should target information channels to reach younger, less educated, unmarried, black respondents, which are at risk for unintended pregnancy.

The Effects of Non-Pharmaceutical Interventions on COVID-19 Cases, Hospitalizations, and Mortality: A Systematic Literature Review and Meta-Analysis.

Introduction: To assess the effects of various non-pharmaceutical interventions (NPI) on cases, hospitalizations, and mortality during the first wave of the COVID-19 pandemic. Methods: To empirically investigate the impacts of different NPIs on COVID-19-related health outcomes, a systematic literature review was conducted. We studied the effects of 10 NPIs on cases, hospitalizations, and mortality across three periodic lags (2, 3, and 4 weeks-or-more following implementation). Articles measuring the impact of NPIs were sourced from three databases by May 10, 2022, and risk of bias was assessed using the Newcastle-Ottawa scale. Results: Across the 44 papers, we found that mask wearing corresponded to decreased per capita cases across all lags (up to -2.71 per 100,000). All NPIs studied except business and bar/restaurant closures corresponded to reduced case growth rates in the two weeks following implementation, while policy stringency and travelling restrictions were most effective after four. While we did not find evidence of reduced deaths in our per capita estimates, policy stringency, masks, SIPOs, limited gatherings, school and business closures were associated with decreased mortality growth rates. Moreover, the two NPIs studied in hospitalizations (SIPOs and mask wearing) showed negative estimates. Conclusions: When assessing the impact of NPIs, considering the duration of effectiveness following implementation has paramount significance. While some NPIs may reduce the COVID-19 impact, others can disrupt the mitigative progression of containing the virus. Policymakers should be aware of both the scale of their effectiveness and duration of impact when adopting these measures for future COVID-19 waves.

Associations of Topics of Discussion on Twitter With Survey Measures of Attitudes, Knowledge, and Behaviors Related to Zika: Probabilistic Study in the United States.

BACKGROUND: Recent outbreaks of Zika virus around the world led to increased discussions about this issue on social media platforms such as Twitter. These discussions may provide useful information about attitudes, knowledge, and behaviors of the population regarding issues that are important for public policy. OBJECTIVE: We sought to identify the associations of the topics of discussions on Twitter and survey measures of Zika-related attitudes, knowledge, and behaviors, not solely based upon the volume of such discussions but by analyzing the content of conversations using probabilistic techniques. METHODS: Using probabilistic topic modeling with US county and week as the unit of analysis, we analyzed the content of Twitter online communications to identify topics related to the reported attitudes, knowledge, and behaviors captured in a national representative survey (N=33,193) of the US adult population over 33 weeks. RESULTS: Our analyses revealed topics related to "congress funding for Zika," "microcephaly," "Zika-related travel discussions," "insect repellent," "blood transfusion technology," and "Zika in Miami" were associated with our survey measures of attitudes, knowledge, and behaviors observed over the period of the study. CONCLUSIONS: Our results demonstrated that it is possible to uncover topics of discussions from Twitter communications that are associated with the Zika-related attitudes, knowledge, and behaviors of populations over time. Social media data can be used as a complementary source of information alongside traditional data sources to gauge the patterns of attitudes, knowledge, and behaviors in a population.

Legacy and social media respectively influence risk perceptions and protective behaviors during emerging health threats: A multi-wave analysis of communications on Zika virus cases.

OBJECTIVE: Both legacy media, such as television and newspapers, and online social media are potentially important but incompletely understood sources of information in the face of emerging public health risks. This research aimed to understand media effects on risk perceptions and behaviors concerning the Zika virus in the United States. METHODS: We analyzed a multi-wave nationally representative survey (N = 29,062) and the volume of communications in social and legacy media (i.e., legacy media data from news sources and databases, N = 2,660 and social media data from Twitter, N = 1,605,752) in the United States between April and October 2016, dates coinciding with the early cases of local transmission of Zika in the United States (i.e., 25 weeks). The present study conducted econometric analyses (i.e., Granger causality tests) to assess the associations of legacy and social media coverage with risk perceptions and protective behaviors in the total sample and specific groups separated by pregnancy status/intent, geographic region, income, education level, age, and ethnicity. RESULTS: The results from the overall sample suggested that changes in the volume of information in legacy and social media (i.e., Twitter) were followed by different changes in community risk perceptions and protective behaviors. Specifically, social media coverage correlated with the level of risk perceptions, whereas the legacy media coverage correlated with the level of protective behaviors. Analyses across different subpopulations, including those of different pregnancy status/intent, geographic Zika risk, income, education level, age, and ethnicity, replicated the social media associations with risk perceptions in most cases. However, legacy media and protective behaviors were linked only in some vulnerable subpopulations (e.g., the less-educated populations). CONCLUSION: Understanding how media coverage relates to Zika risk perceptions and protective behaviors will help to facilitate effective risk communications by healthcare professionals and providers, particularly when a health risk emerges.