Resistance to COVID-19 vaccination and the social contract: evidence from Italy.

Confronted with stalled vaccination efforts against COVID-19, many governments embraced mandates and other measures to incentivize vaccination that excluded the unvaccinated from aspects of social and economic life. Even still, many citizens remained unvaccinated. We advance a social contract framework for understanding who remains unvaccinated and why. We leverage both observational and individual-level survey evidence from Italy to study the relationship between vaccination status and social context, social trust, political partisanship, and adherence to core institutional structures such as the rule of law and collective commitments. We find that attitudes toward the rule of law and collective commitments outside the domain of vaccination are strongly associated with compliance with vaccine mandates and incentives. Partisanship also corresponds with vaccine behaviors, as supporters of parties whose leaders criticized aggressive policies to incentivize or mandate vaccination and emphasized individual liberty are least likely to comply. Our findings suggest appeals emphasizing individual benefits may be more effective than appeals emphasizing collective responsibility.

Persistent drop in confidence following US recommended pause of Ad26.COV2.S vaccine administration.

The Janssen COVID-19 vaccine came to market in February 2021 as the first non-mRNA and first single-dose formula approved for use in the US. In April 2021, a temporary pause was recommended for the vaccine after the discovery of rare but serious post-vaccination side-effects. We fielded a large-scale nationally representative survey (n = 401,398) on individual confidence in each of the COVID-19 vaccine formulas available in the US before, during, and after this pause. We find widespread loss of confidence in the Janssen vaccine across gender, age, and other demographics, which persisted over time and after lifting of the halt. Despite this drop, overall reasons for remaining unvaccinated were stable and there was a concurrent minor bump in confidence towards other vaccine formulas. This contrast between the persistent reduction in confidence in the Janssen vaccine and the apparent maintenance of the broader campaign's integrity, highlights the complex dynamics and downstream effects of the pause.

COVID-19 booster uptake among US adults: Assessing the impact of vaccine attributes, incentives, and context in a choice-based experiment.

OBJECTIVE: Evidence shows that booster shots offer strong protection against the Omicron variant of COVID-19. However, we know little about why individuals would receive a booster compared to the initial decision to vaccinate. We investigate and assess the factors that affect individuals' reported willingness to receive the COVID-19 vaccine booster. This information can aid in tailoring public health messaging to communicate attributes that are associated with individuals' attitudes toward the COVID-19 booster. RATIONALE: Existing research provides little insight into whether the same factors that affect Americans' likelihood of accepting initial vaccination against COVID-19 also affect booster uptake. Our experiment also examines the influence of contextual information about a novel variant on willingness to receive a booster. METHODS: We administered a conjoint experiment (N = 2740 trials) in a survey of fully vaccinated US adults that had not yet received a COVID-19 booster (N = 548) to assess the impact of varied vaccine attributes on willingness to receive a booster. RESULTS: The most important factors associated with higher willingness to receive a booster were efficacy, manufacturer, and the size of a financial incentive. Protection duration and protection against future variants vs. only current variants had modest influence. A contextual prime reporting that some public health experts believe the Omicron variant is more contagious, but less lethal than those previously seen, significantly increased favorability toward boosters. This provides potential motivation and guidance for vaccination campaigns to emphasize these variant-specific traits. CONCLUSION: With several vaccines with varying degrees of efficacy available to consumers, emphasizing boosters with a high efficacy would likely improve attitudes toward boosters. Financial incentives and predispositions toward manufacturers also matter. Concerns about more contagious variants may spur uptake, even if such variants are less lethal.

Communication about vaccine efficacy and COVID-19 vaccine choice: Evidence from a survey experiment in the United States.

While mass vaccination campaigns against COVID-19 have inoculated almost 200 million Americans and billions more worldwide, significant pockets of vaccine hesitancy remain. Research has firmly established that vaccine efficacy is an important driver of public vaccine acceptance and choice. However, current vaccines offer widely varying levels of protection against different adverse health outcomes of COVID-19. This study employs an experiment embedded on a survey of 1,194 US adults in June 2021 to examine how communications about vaccine efficacy affect vaccine choice. The experiment manipulated how vaccine efficacy was defined across four treatments: (1) protection against symptomatic infection; (2) protection against severe illness; (3) protection against hospitalization/death; (4) efficacy data on all three metrics. The control group received no efficacy information. Subjects were asked to choose between a pair of vaccines-a one-dose viral vector vaccine or two-dose mRNA vaccine-whose efficacy data varied across the four experimental treatment groups. Efficacy data for each vaccine on each dimension were adapted from clinical trial data on the Johnson & Johnson/Janssen and Pfizer/BioNTech vaccines. Among all respondents, only modest preference gaps between the two vaccines emerged in the control group and when the two vaccines' roughly equivalent efficacy data against hospitalization and death were reported. Strong preferences for a two-dose mRNA vaccine emerged in treatments where its higher efficacy against symptomatic or severe illness was reported, as well as in the treatment where data on all three efficacy criteria were reported. Unvaccinated respondents preferred a one-dose viral vector vaccine when only efficacy data against hospitalization or death was presented. Black and Latino respondents were significantly more likely to choose the one-shot viral vector vaccine in the combined efficacy treatment than were whites. Results speak to the importance of understanding how communications about vaccine efficacy affect public preferences in an era of increasing uncertainty about efficacy against variants.

COVID-19 Infodemic and the Efficacy of Interventions Intended to Reduce Misinformation

The COVID-19 pandemic has prompted social media platforms to take unprecedented steps—ranging from false tags to journalistic factchecks—to stanch the flow of misinformation that could pose a health risk. However, there is little evidence about the relative efficacy of these approaches in this unique context of a pandemic. Using a pair of survey experiments, we examine whether false tags and journalistic factchecks reduce accuracy misperceptions and sharing propensity on social media that can spread false claims. False tags had little effect on subjects' accuracy assessments and social media sharing. Journalistic factchecks that offer accurate information to counter misinformation were more effective in reducing both misperceptions and sharing on social media. Further, we find no evidence of partisan backfire effects, even in response to interventions against claims with a plausible partisan valence. Our results suggest that journalistic factchecks provide an effective counternarrative to COVID-19 misinformation even in the context of the increasing politicization of America's pandemic response and polarization more generally. [ FROM AUTHOR] Copyright of Public Opinion Quarterly is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

The Relationship between US Adults' Misconceptions about COVID-19 Vaccines and Vaccination Preferences.

While mass vaccination has blunted the pandemic in the United States, pockets of vaccine hesitancy remain. Through a nationally representative survey of 1027 adult Americans conducted in February 2021, this study examined individual misconceptions about COVID-19 vaccine safety; the demographic factors associated with these misconceptions; and the relationship between misconceptions and willingness to vaccinate. Misconceptions about vaccine safety were widespread. A sizeable minority (40%) believed that vaccine side effects are commonly severe or somewhat severe; 85% significantly underestimated the size and scale of the clinical trials; and a sizeable share believed either that the vaccines contain live coronavirus (10%) or were unsure (38%), a proxy for fears that vaccination itself may cause infection. These misconceptions were particularly acute among Republicans, Blacks, individuals with lower levels of educational attainment, and unvaccinated individuals. Perceived side effect severity and underestimating the size of the clinical trials were both significantly associated with vaccine hesitancy.

Public attitudes toward COVID-19 vaccination: The role of vaccine attributes, incentives, and misinformation.

While efficacious vaccines have been developed to inoculate against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; also known as COVID-19), public vaccine hesitancy could still undermine efforts to combat the pandemic. Employing a survey of 1096 adult Americans recruited via the Lucid platform, we examined the relationships between vaccine attributes, proposed policy interventions such as financial incentives, and misinformation on public vaccination preferences. Higher degrees of vaccine efficacy significantly increased individuals' willingness to receive a COVID-19 vaccine, while a high incidence of minor side effects, a co-pay, and Emergency Use Authorization to fast-track the vaccine decreased willingness. The vaccine manufacturer had no influence on public willingness to vaccinate. We also found no evidence that belief in misinformation about COVID-19 treatments was positively associated with vaccine hesitancy. The findings have implications for public health strategies intending to increase levels of community vaccination.

Factors Associated With US Adults' Likelihood of Accepting COVID-19 Vaccination.

Importance: The development of a coronavirus disease 2019 (COVID-19) vaccine has progressed at unprecedented speed. Widespread public uptake of the vaccine is crucial to stem the pandemic. Objective: To examine the factors associated with survey participants' self-reported likelihood of selecting and receiving a hypothetical COVID-19 vaccine. Design, Setting, and Participants: A survey study of a nonprobability convenience sample of 2000 recruited participants including a choice-based conjoint analysis was conducted to estimate respondents' probability of choosing a vaccine and willingness to receive vaccination. Participants were asked to evaluate their willingness to receive each hypothetical vaccine individually. The survey presented respondents with 5 choice tasks. In each, participants evaluated 2 hypothetical COVID-19 vaccines and were asked whether they would choose vaccine A, vaccine B, or neither vaccine. Vaccine attributes included efficacy, protection duration, major adverse effects, minor adverse effects, US Food and Drug Administration (FDA) approval process, national origin of vaccine, and endorsement. Levels of each attribute for each vaccine were randomly assigned, and attribute order was randomized across participants. Survey data were collected on July 9, 2020. Main Outcomes and Measures: Average marginal component effect sizes and marginal means were calculated to estimate the relationship between each vaccine attribute level and the probability of the respondent choosing a vaccine and self-reported willingness to receive vaccination. Results: A total of 1971 US adults responded to the survey (median age, 43 [interquartile range, 30-58] years); 999 (51%) were women, 1432 (73%) White, 277 (14%) were Black, and 190 (10%) were Latinx. An increase in efficacy from 50% to 70% was associated with a higher probability of choosing a vaccine (coefficient, 0.07; 95% CI, 0.06-0.09), and an increase from 50% to 90% was associated with a higher probability of choosing a vaccine (coefficient, 0.16; 95% CI, 0.15-0.18). An increase in protection duration from 1 to 5 years was associated with a higher probability of choosing a vaccine (coefficient, 0.05 95% CI, 0.04-0.07). A decrease in the incidence of major adverse effects from 1 in 10 000 to 1 in 1 000 000 was associated with a higher probability of choosing a vaccine (coefficient, 0.07; 95% CI, 0.05-0.08). An FDA emergency use authorization was associated with a lower probability of choosing a vaccine (coefficient, -0.03; 95% CI, -0.04 to -0.01) compared with full FDA approval. A vaccine that originated from a non-US country was associated with a lower probability of choosing a vaccine (China: -0.13 [95% CI, -0.15 to -0.11]; UK: -0.04 [95% CI, -0.06 to -0.02]). Endorsements from the US Centers for Disease Control and Prevention (coefficient, 0.09; 95% CI, 0.07-0.11) and the World Health Organization (coefficient, 0.06; 95% CI, 0.04-0.08), compared with an endorsement from President Trump were associated with higher probabilities of choosing a vaccine. Analyses of participants' willingness to receive each vaccine when assessed individually yielded similar results. An increase in efficacy from 50% to 90% was associated with a 10% higher marginal mean willingness to receive a vaccine (from 0.51 to 0.61). A reduction in the incidence of major side effects was associated with a 4% higher marginal mean willingness to receive a vaccine (from 0.54 to 0.58). A vaccine originating in China was associated with a 10% lower willingness to receive a vaccine vs one developed in the US (from 0.60 to 0.50) Endorsements from the Centers for Disease Control and Prevention and World Health Organization were associated with increases in willingness to receive a vaccine (7% and 6%, respectively) from a baseline endorsement by President Trump (from 0.52 to 0.59 and from 0.52 to 0.58, respectively). Conclusions and Relevance: In this survey study of US adults, vaccine-related attributes and political characteristics were associated with self-reported preferences for choosing a hypothetical COVID-19 vaccine and self-reported willingness to receive vaccination. These results may help inform public health campaigns to address vaccine hesitancy when a COVID-19 vaccine becomes available.