Transmission of Vaccination Attitudes and Uptake Based on Social Contagion Theory: A Scoping Review

Patterns in COVID-19 vaccination among children aged 5-11 years in Alberta, Canada: Lessons for future vaccination campaigns

Objectives

In Alberta, Canada, the COVID-19 vaccination program for children aged 5-11 years was launched on November 26, 2021. Our objectives were to determine the cumulative vaccine coverage, stratified by age, during the first thirteen months of vaccine availability, and investigate factors associated with vaccine uptake.

Study design

This retrospective cohort study used population-based administrative health data.

Methods

We determined cumulative vaccine coverage among 5-11 year olds, stratified by year of age, during the first thirteen months of vaccine availability and used a modified Poisson regression to evaluate factors associated with vaccine uptake.

Results

Of 377,103 eligible children, 44.8 % (n = 168,761) received one or more doses of COVID-19 vaccine during the study period (9.7 % received only one dose, while 35.1 % received 2 doses). Almost 90 % of initial doses were received within the first two months of vaccine availability. We found a step-wise relationship between increasing child age and higher vaccine coverage.

Conclusions

Plateaued vaccine uptake indicates a need to adapt programmatic efforts to encourage parents to act on positive vaccination intentions, and reach the large contingent of parents who have reported that they remain undecided. In order to promote vaccine uptake, messaging around vaccine safety and need should be tailored to child age, rather than uniformly applied across the 5-11 year age range.

Associations Between Social Networks and COVID-19 Vaccine Uptake in 4 Rural Alabama Counties: Survey Findings

OBJECTIVES

The COVID-19 pandemic demonstrated how vaccination decisions are influenced by misinformation, disinformation, and social pressures, leading to varied and inequitable uptake rates. In this study, we examined how COVID-19 vaccine messages received via social networks were associated with vaccine uptake in rural Alabama.

METHODS

From November 2021 through March 2022, we collected 700 responses to a telephone survey administered in 4 rural Alabama counties. We asked respondents to indicate whether certain social relationships (eg, family, businesses) tried to influence them to (1) obtain or (2) avoid a COVID-19 vaccine. We used χ2 tests, Kruskal-Wallis tests, Mantel-Haenszel χ2 tests, and Fisher exact tests to examine the associations between vaccination status and survey responses.

RESULTS

Respondents in majority-African American counties were significantly more likely than those in majority-White counties to have received ≥1 dose of COVID-19 vaccine (89.8% vs 72.3%; P < .001). Respondents who received ≥1 dose had a significantly higher mean age than those who had not (58.0 vs 39.0 years; P < .001). Respondents who were encouraged to get vaccinated by religious leaders were more likely to have received ≥1 dose (P = .001), and those who were encouraged to avoid vaccination by family (P = .007), friends (P = .02), coworkers (P = .003), and health care providers (P < .001) were less likely to have received ≥1 dose. Respondents with more interpersonal relationships that encouraged them to avoid vaccination were more likely to be unvaccinated (P < .001).

CONCLUSIONS

Interpersonal relationships and demographic characteristics appeared to be important in COVID-19 vaccine decision-making in rural Alabama. Further research needs to identify how to facilitate vaccine-positive interpersonal relationships, such as peer mentoring and trusted messenger interventions.

The role of vaccine status homophily in the COVID-19 pandemic: a cross-sectional survey with modelling

BACKGROUND

Vaccine homophily describes non-heterogeneous vaccine uptake within contact networks. This study was performed to determine observable patterns of vaccine homophily, as well as the impact of vaccine homophily on disease transmission within and between vaccination groups under conditions of high and low vaccine efficacy.

METHODS

Residents of British Columbia, Canada, aged ≥ 16 years, were recruited via online advertisements between February and March 2022, and provided information about vaccination status, perceived vaccination status of household and non-household contacts, compliance with COVID-19 prevention guidelines, and history of COVID-19. A deterministic mathematical model was used to assess transmission dynamics between vaccine status groups under conditions of high and low vaccine efficacy.

RESULTS

Vaccine homophily was observed among those with 0, 2, or 3 doses of the vaccine. Greater homophily was observed among those who had more doses of the vaccine (p < 0.0001). Those with fewer vaccine doses had larger contact networks (p < 0.0001), were more likely to report prior COVID-19 (p < 0.0001), and reported lower compliance with COVID-19 prevention guidelines (p < 0.0001). Mathematical modelling showed that vaccine homophily plays a considerable role in epidemic growth under conditions of high and low vaccine efficacy. Furthermore, vaccine homophily contributes to a high force of infection among unvaccinated individuals under conditions of high vaccine efficacy, as well as to an elevated force of infection from unvaccinated to suboptimally vaccinated individuals under conditions of low vaccine efficacy.

INTERPRETATION

The uneven uptake of COVID-19 vaccines and the nature of the contact network in the population play important roles in shaping COVID-19 transmission dynamics.

Willingness to accept monkeypox vaccine and its correlates among men who have sex with men in Southern China: a web-based online cross-sectional study

Background

The May 2022 global outbreak of monkeypox (MPX) poses a threat to the health of men who have sex with men. However, there is limited data on the willingness of MSM to receive monkeypox vaccination in Southern China. This study aimed to assess the knowledge of MPX, concerns regarding MPX, and willingness to receive monkeypox vaccination, as well as their correlates, among MSM in China.

Methods

We conducted a Web-based online survey of MSM in Southern China from August to September 2022. Data were collected on the socio-demographic characteristics, knowledge, worries, concerns regarding MPX and willingness to receive monkeypox vaccination. Multivariate logistic regression was employed to explore the factors associated with willingness to receive monkeypox vaccination.

Results

A total of 1903 participants completed the survey. Among them, approximately 69.9% reported being aware of MPX awareness, 94.1% of the participants supported the promotion of monkeypox vaccination. The majority of participants (91.4%) expressed their willingness to receive monkeypox vaccination. Participants who considered monkeypox vaccination safe [adjusted odds ratio (aOR) = 4.82, 95% CI: 1.35-17.18], agreed on the necessity of government promotion of monkeypox vaccination in China (aOR = 6.03, 95% CI: 1.07-33.93), believed in prioritizing monkeypox vaccination for MSM (aOR = 5.01, 95% CI: 1.10-22.71), and had friends or sexual partners who had already received the monkeypox or smallpox vaccination (aOR = 10.37, 95% CI: 2.11-50.99) are more likely to be vaccinated. Conversely, married individuals (aOR = 0.13, 95% CI: 0.03-0.47), those engaging in anal sex 4-6 times per week in the past 3 months (aOR = 0.26, 95% CI: 0.09-0.77) expressed hesitancy toward monkeypox vaccination.

Conclusion

There was a high willingness to receive monkeypox vaccination among MSM in China. The hesitancy toward the monkeypox vaccine can be effectively mitigated by addressing concerns about its safety and potential adverse reactions. Moreover, increasing acceptance of the monkeypox vaccination among MSM and their peers is crucial, as social influence significantly impacts vaccine attitudes and behaviors.

Addressing COVID-19 Vaccine Hesitancy With Community Distribution of Conversation Cards

To increase community conversations about COVID-19 vaccine hesitancy, we distributed vaccine cardholders and conversation cards to 6000 newly vaccinated adults at vaccination sites and encouraged them to talk with unvaccinated friends and family members. In 257 onsite exit interviews, we found that cardholders and conversation cards were well liked, and most recipients expected to use them. Follow-up surveys two weeks later showed that 51% of respondents used a card to start a conversation and 41% gave a card to an unvaccinated friend or family member. (Am J Public Health. 2024;114(S1):S87-S91. https://doi.org/10.2105/AJPH.2023.307481).

Can physicians and schools mitigate social inequalities in human papillomavirus vaccine awareness, uptake and vaccination intention among adolescents? A cross-sectional study, France, 2021 to 2022

BackgroundIn France, human papillomavirus (HPV) vaccination coverage varies across socioeconomic levels.AimWe aimed at assessing HPV vaccine awareness, uptake and vaccination intention among adolescents in France.MethodsIn a cluster-randomised study, 13-15-year-old students in 61 French middle schools completed a web-based questionnaire. We used multivariable logistic regression to evaluate determinants of HPV vaccine awareness, self-reported uptake and vaccination intention among unvaccinated students and interaction terms to explore effects of visits to family physician and remembering school lessons on vaccination. The French deprivation index of school municipalities served as proxy for socioeconomic levels.ResultsAmong 6,992 participants, awareness was significantly associated with parental education (odds ratio (OR) = 0.82; 95% confidence interval (CI): 0.71-0.95), language spoken at home (OR = 0.59; 95% CI: 0.52-0.66) and deprivation level (OR = 0.57; 95% CI: 0.44-0.71), regardless of physician visit or school lessons. Vaccine uptake was associated with parental education without a recent physician visit (OR = 0.31; 95% CI: 0.16-0.59, vs OR = 0.64; 95% CI: 0.52-0.78 with a visit, interaction p = 0.045). Vaccination intention among unvaccinated was associated with deprivation level (moderate-low vs low) among students not remembering school lessons on vaccination (OR = 0.17; 95% CI: 0.05-0.62, vs OR = 0.93; 95% CI: 0.51-1.67 remembering school lessons, interaction p = 0.022). Parental education was associated with vaccination intention among students reporting a physician visit (OR = 0.41; 95% CI: 0.26-0.64 vs OR = 1.05; 95% CI: 0.50-2.20 without a visit, interaction p = 0.034).ConclusionOur results suggest that healthcare and school could promote vaccination and mitigate social inequalities in HPV vaccination coverage.

A qualitative study exploring the social contagion of attitudes and uptake of COVID-19 vaccinations

Vaccination attitudes and uptake can spread within social networks. This study aims to understand the perceived social contagion mechanisms of vaccination uptake in the context of COVID-19 pandemic. Eleven semi-structured interviews were conducted following a purposive sampling of three hesitant, three anti- COVID-19 vaccine and five pro- COVID-19 vaccine (27% females). Thematic Analysis suggested two general themes reflecting the type of contagion: 1) information contagion and 2) behavior contagion. Transcending these themes was the notion of ownership of choice/decision. Almost all participants used the media and experts as the main source of information regarding vaccination. They influenced - and they were being influenced by - friends and family members with whom they share similar traits and attitudes and have a close relationship of trust and intimacy. Also, being exposed to positive attitudes and beliefs toward vaccination and COVID-19 vaccines, enhanced vaccination behaviors. However, the vaccination decision-making process was not perceived as a passive process - there was ownership over the decisions made. This study highlights the perceived mechanisms of social contagion. It also suggests that the meaning individuals pose on their social world is crucial on their decision-making. Policymakers are advised to consider including social networks of individuals and trusted sources (i.e. healthcare providers) when delivering interventions or educational campaigns on vaccinations.

Correlations between COVID-19 cases and temperature, air humidity, and social isolating rate with cross wavelet transform and wavelet coherence: Case study of New York and São Paulo cities

The COVID-19 pandemic originated in 2019 and has become an endemic disease that we must learn to live with, similar to other strains of influenza. The Organization (WHO) declared on May 5, 2023, in Geneva, Switzerland, the end of the Public Health Emergency of International Concern regarding COVID-19. As vaccines become more widely available and the pandemic appears to be improved, our focus shifts to the challenges we still face. Understanding how external factors like temperature, air humidity, and social isolation impact the spread of the SARS-CoV-2 virus remains a crucial challenge beyond our control. In this study, potential links between the number of COVID-19 cases in São Paulo City (SPC) and New York City (NWC) were explored. Our analysis was carried out utilizing the continuous wavelet transform, alongside other tools such as cross-wavelet transform and wavelet coherence. Based on our findings, there appears to be a correlation between the variables related to low frequencies, which aligns with previous research on the topic. Particularly, our research has revealed a connection between COVID-19 cases and factors such as temperature, air humidity, and social isolation rates. Regarding the latter, our findings indicate that implementing social distancing measures was a wise public policy decision, although the correlation with daily COVID-19 cases requires careful analysis. For this study, we analyzed data from February of 2020, when the first cases were reported in the cities under investigation, SPC and NWC, up until December 31, 2022, by which time the vaccination campaign was well under way.

Barriers to and facilitators of populational adherence to prevention and control measures of COVID-19 and other respiratory infectious diseases: a qualitative evidence synthesis

AIMS

To summarise the evidence on barriers to and facilitators of population adherence to prevention and control measures for coronavirus disease 2019 (COVID-19) and other respiratory infectious diseases.

METHODS

A qualitative synthesis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis and the Cochrane Effective Practice and Organization of Care: Qualitative Evidence Synthesis. We performed an electronic search on MEDLINE, Embase and PsycINFO from their inception to March 2023.

RESULTS

We included 71 studies regarding COVID-19, pneumonia, tuberculosis, influenza, pertussis and H1N1, representing 5966 participants. The measures reported were vaccinations, physical distancing, stay-at-home policy, quarantine, self-isolation, facemasks, hand hygiene, contact investigation, lockdown, infection prevention and control guidelines, and treatment. Tuberculosis-related measures were access to care, diagnosis and treatment completion. Analysis of the included studies yielded 37 barriers and 23 facilitators.

CONCLUSIONS

This review suggests that financial and social support, assertive communication, trust in political authorities and greater regulation of social media enhance adherence to prevention and control measures for COVID-19 and infectious respiratory diseases. Designing and implementing effective educational public health interventions targeting the findings of barriers and facilitators highlighted in this review are key to reducing the impact of infectious respiratory diseases at the population level.

Patient-Provider Health Communication Strategies: Enhancing HPV Vaccine Uptake among Adolescents of Color

Cervical cancer remains a public health issue in the United States, particularly among stigmatized racial and ethnic populations. The human papillomavirus (HPV) vaccine has been clinically proven to prevent cervical cancers, and other HPV-associated cancers, among men and women. However, HPV vaccine uptake is suboptimal; only 55% of adolescents complete the two-dose series by age 15. Past research has shown that provider HPV vaccine communication for people of marginalized races/ethnicities is subpar. This article focuses on provider communication strategies to promote HPV vaccine uptake effectively and equitably. The authors reviewed the literature on evidence-based patient-provider HPV vaccine communication techniques to create a set of communication language providers could use and avoid using to enhance HPV vaccine acceptance and uptake among adolescents of marginalized racial and ethnic groups. Evidence has shown that information and the manner of dissemination are critical for influencing HPV vaccine uptake. These communication strategies must be suited to the context of the targeted population, and the message content can be broadly categorized into source, content, and modality. Strategies to improve patient-provider communication among adolescents of color using source, modality, and content include the following: (1) Source: increase provider self-efficacy to provide the recommendation, building rapport between providers and parents; (2) Content: persistent, forceful language with minimal acquiescence should be employed, reframing the conversation focus from sex to cancer; and (3) Modality: use multiple vaccine reminder modalities, and work with the community to culturally adapt the vaccination language. Utilizing effective behavior-change communication adapted for adolescents of color can reduce missed opportunities for HPV prevention, potentially decreasing racial and ethnic disparities in HPV-related morbidity and mortality.

Political network composition predicts vaccination attitudes

Political polarization is growing rapidly in the United States and has been linked to politicized public health issues including vaccination. Political homogeneity among one's interpersonal relationships may predict polarization levels and partisan bias. In this study, we analyzed if political network structure predicted partisan beliefs about the COVID-19 vaccine, beliefs about vaccines in general, and COVID-19 vaccine uptake. Personal networks were measured by whom the respondent discussed "important matters" with to obtain a list of individuals who are close to the respondent. The number of associates listed who share the political identity or vaccine status with the respondent was calculated as a measure of homogeneity. We find that having more Republicans and unvaccinated individuals in one's network predicted lower vaccine confidence whereas having more Democrats and vaccinated individuals in one's network predicted higher vaccine confidence. Exploratory network analyses revealed that non-kin others are especially impactful on vaccine attitudes when those network connections are also Republican and unvaccinated.

Polarization in COVID-19 Vaccine Discussion Networks

The emergence of COVID-19 spurred the fastest development of a vaccine in history. Yet, a large proportion of Americans remain hesitant to receive it. Our paper investigates how the social networks we inhabit might explain persistent vaccine hesitancy. We argue that the COVID-19 vaccination status of respondents' closest associates inhibits or motivates their decision to receive a COVID-19 vaccine. To test our argument, we conduct an original survey asking respondents a battery of questions about the people with whom individuals most frequently discuss vaccines and COVID-19. Our survey reports that individuals' discussion networks are polarized by vaccination status. Concurrently, there is a strong association between the social network's vaccination status and the respondent's vaccination status. This association is so robust that partisanship does not moderate the association between discussants' vaccination status and respondents' vaccination status. Together, our results imply that unvaccinated individuals remain hesitant because they face reinforcing social pressure from their closest associates. The unique timing of our survey, during an unprecedented vaccination campaign against a novel disease, offers a snapshot of how relationships may affect attitudes.

Qualitative Insights into Vaccine Uptake of Nursing Staff in Long-Term Care Facilities in Finland

Vaccine hesitancy and refusal have undermined COVID-19 vaccination efforts of nursing staff. This study aimed to identify behavioral factors associated with COVID-19 vaccine uptake among unvaccinated nursing staff in long-term care facilities (LTCF) in Finland. Methodology: The study was based on the Theoretical Domains Framework. Data were collected through qualitative in-depth interviews among nursing staff and managers of LTCFs. The analysis was based on thematic analysis. We identified seven behavioral domains, with several themes, that reduced the staff's intention to get vaccinated: knowledge (information overload, inability to identify trustworthy information sources, lack of vaccine-specific and understandable scientific information), beliefs about consequences (incorrect perceptions about the vaccine effectiveness, and lack of trust in the safety of the vaccine), social influences (influence of family and friends), reinforcement (limited abilities of the management to encourage vaccination), beliefs about capabilities (pregnancy or desire to get pregnant), psychological factors (coping with changing opinion), and emotions (confusion, suspicion, disappointment, and fatigue). We also identified three behavioral domains that encouraged vaccine uptake: social influences (trust in health authorities), environmental context and resources (vaccination logistics), and work and professional role (professional pride). The study findings can help authorities to develop tailored vaccine promotion strategies for healthcare workers in LTCFs.

COVID-19 Vaccine Hesitancy: Disadvantaged Groups’ Experience with Perceived Barriers, Cues to Action, and Attitudes

Purpose

Drawing from the Health Belief Model, we explored how disadvantaged groups in the U.S., including Black, Hispanic, less educated and wealthy individuals, experienced perceived barriers and cues to action in the context of the COVID-19 vaccination.

Design

A cross-sectional survey administered in March 2021.

Setting

USA

Subjects

A national sample of U.S. residents (n = 795) recruited from Prolific.

Measures

Perceived barriers (clinical, access, trust, religion/spiritual), cues to action (authorities, social circles), attitudes toward COVID-19 vaccination.

Analysis

Factor analysis and Structural Equation Model (SEM) were performed in STATA 16.

Results

Black and less educated individuals experienced higher clinical barriers (CI [.012, .33]; CI [.027, .10]), trust barriers (CI [.49, .92]; CI [.057, .16]), and religious/spiritual barriers (CI [.28, .66]; CI [.026, .11]). Hispanics experienced lower levels of clinical barriers (CI [-.42, .0001]). Clinical, trust, and religious/spiritual barriers were negatively related to attitudes toward vaccination (CI [-.45, −.15]; CI [-.79, −.51]; CI [-.43, −.13]). Black and less educated individuals experienced fewer cues to action by authority (CI [-.47, −.083]; CI [-.093, −.002]) and social ties (CI [-.75, −.33]; CI [-.18, −.080]). Lower-income individuals experienced fewer cues to action by social ties (CI [-.097, −.032]). Cues from social ties were positively associated with vaccination attitudes (CI [.065, .26]).

Conclusion

Communication should be personalized to address perceived barriers disadvantaged groups differentially experience and use sources who exert influences on these groups.

Spatial clustering in vaccination hesitancy: The role of social influence and social selection

The phenomenon of vaccine hesitancy behavior has gained ground over the last three decades, jeopardizing the maintenance of herd immunity. This behavior tends to cluster spatially, creating pockets of unprotected sub-populations that can be hotspots for outbreak emergence. What remains less understood are the social mechanisms that can give rise to spatial clustering in vaccination behavior, particularly at the landscape scale. We focus on the presence of spatial clustering, and aim to mechanistically understand how different social processes can give rise to this phenomenon. In particular, we propose two hypotheses to explain the presence of spatial clustering: (i) social selection, in which vaccine-hesitant individuals share socio-demographic traits, and clustering of these traits generates spatial clustering in vaccine hesitancy; and (ii) social influence, in which hesitant behavior is contagious and spreads through neighboring societies, leading to hesitant clusters. Adopting a theoretical spatial network approach, we explore the role of these two processes in generating patterns of spatial clustering in vaccination behaviors under a range of spatial structures. We find that both processes are independently capable of generating spatial clustering, and the more spatially structured the social dynamics in a society are, the higher spatial clustering in vaccine-hesitant behavior it realizes. Together, we demonstrate that these processes result in unique spatial configurations of hesitant clusters, and we validate our models of both processes with fine-grain empirical data on vaccine hesitancy, social determinants, and social connectivity in the US. Finally, we propose, and evaluate the effectiveness of two novel intervention strategies to diminish hesitant behavior. Our generative modeling approach informed by unique empirical data provides insights on the role of complex social processes in driving spatial heterogeneity in vaccine hesitancy.

SARS-CoV-2 transmission and impacts of unvaccinated-only screening in populations of mixed vaccination status

Screening programs that test only the unvaccinated population have been proposed and implemented to mitigate SARS-CoV-2 spread, implicitly assuming that the unvaccinated population drives transmission. To evaluate this premise and quantify the impact of unvaccinated-only screening programs, we introduce a model for SARS-CoV-2 transmission through which we explore a range of transmission rates, vaccine effectiveness scenarios, rates of prior infection, and screening programs. We find that, as vaccination rates increase, the proportion of transmission driven by the unvaccinated population decreases, such that most community spread is driven by vaccine-breakthrough infections once vaccine coverage exceeds 55% (omicron) or 80% (delta), points which shift lower as vaccine effectiveness wanes. Thus, we show that as vaccination rates increase, the transmission reductions associated with unvaccinated-only screening decline, identifying three distinct categories of impact on infections and hospitalizations. More broadly, these results demonstrate that effective unvaccinated-only screening depends on population immunity, vaccination rates, and variant.

Herd immunity and epidemic size in networks with vaccination homophily

We study how the herd immunity threshold and the expected epidemic size depend on homophily with respect to vaccine adoption. We find that the presence of homophily considerably increases the critical vaccine coverage needed for herd immunity and that strong homophily can push the threshold entirely out of reach. The epidemic size monotonically increases as a function of homophily strength for a perfect vaccine, while it is maximized at a nontrivial level of homophily when the vaccine efficacy is limited. Our results highlight the importance of vaccination homophily in epidemic modeling.

Uptake of COVID-19 Vaccination Among Frontline Workers in California State Prisons

Question

In California prisons, what proportion of prison staff who have direct contact with residents are unvaccinated, and what are their characteristics?

Findings

In this cohort study of 23 472 custody staff and 7617 health care staff in California state prisons, 14 317 custody staff (61%) and 2819 (36%) health care staff remained unvaccinated through June 30, 2021, despite widespread vaccine availability. Unvaccinated staff were younger and more likely to have had COVID-19; they were also more likely to work alongside other unvaccinated staff and live in communities with relatively low rates of vaccination.

Meaning

The study results suggest that low vaccination rates among prison staff pose continuing risks.

Importance

Prisons and jails are high-risk environments for COVID-19. Vaccination levels among workers in many such settings remain markedly lower than those of residents and members of surrounding communities. The situation is troubling because prison staff are a key vector for COVID-19 transmission.

Objective

To assess patterns and timing of staff vaccination in California state prisons and identify individual-level and community-level factors associated with remaining unvaccinated.

Design, Setting, and Participants

This cohort study used data from December 22, 2020, through June 30, 2021, to quantify the fractions of staff and incarcerated residents who remained unvaccinated among 23 472 custody and 7617 health care staff who worked in roles requiring direct contact with residents at 33 of the 35 prisons operated by the California Department of Corrections and Rehabilitation. Multivariable probit regressions assessed demographic, community, and peer factors associated with staff vaccination uptake.

Main Outcomes and Measures

Remaining unvaccinated throughout the study period.

Results

Of 23 472 custody staff, 3751 (16%) were women, and 1454 (6%) were Asian/Pacific Islander individuals, 1571 (7%) Black individuals, 9008 (38%) Hispanic individuals, and 6666 (28%) White individuals. Of 7617 health care staff, 5434 (71%) were women, and 2148 (28%) were Asian/Pacific Islander individuals, 1201 (16%) Black individuals, 1409 (18%) Hispanic individuals, and 1771 (23%) White individuals. A total of 6103 custody staff (26%) and 3961 health care staff (52%) received 1 or more doses of a COVID-19 vaccine during the first 2 months vaccines were offered, but vaccination rates stagnated thereafter. By June 30, 2021, 14 317 custody staff (61%) and 2819 health care staff (37%) remained unvaccinated. In adjusted analyses, remaining unvaccinated was positively associated with younger age (custody staff: age, 18-29 years vs ≥60 years, 75% [95% CI, 73%-76%] vs 45% [95% CI, 42%-48%]; health care staff: 52% [95% CI, 48%-56%] vs 29% [95% CI, 27%-32%]), prior COVID-19 infection (custody staff: 67% [95% CI, 66%-68%] vs 59% [95% CI, 59%-60%]; health care staff: 44% [95% CI, 42%-47%] vs 36% [95% CI, 36%-36%]), residing in a community with relatively low rates of vaccination (custody staff: 75th vs 25th percentile:, 63% [95% CI, 62%-63%] vs 60% [95% CI, 59%-60%]; health care staff: 40% [95% CI, 39%-41%] vs 34% [95% CI, 33%-35%]), and sharing shifts with coworkers who had relatively low rates of vaccination (custody staff: 75th vs 25th percentile, 64% [95% CI, 62%-66%] vs 59% [95% CI, 57%-61%]; health care staff: 38% [95% CI, 36%-41%] vs 35% [95% CI, 31%-39%]).

Conclusions and Relevance

This cohort study of California state prison custody and health care staff found that vaccination uptake plateaued at levels that posed ongoing risks of further outbreaks in the prisons and continuing transmission from prisons to surrounding communities. Prison staff decisions to forgo vaccination appear to be multifactorial, and vaccine mandates may be necessary to achieve adequate levels of immunity in this high-risk setting.

It Takes a Village to Trust Science: Towards a (Thoroughly) Social Approach to Public Trust in Science

In this paper, I distinguish three general approaches to public trust in science, which I call the individual approach, the semi-social approach, and the social approach, and critically examine their proposed solutions to what I call the problem of harmful distrust. I argue that, despite their differences, the individual and the semi-social approaches see the solution to the problem of harmful distrust as consisting primarily in trying to persuade individual citizens to trust science and that both approaches face two general problems, which I call the problem of overidealizing science and the problem of overburdening citizens. I then argue that in order to avoid these problems we need to embrace a (thoroughly) social approach to public trust in science, which emphasizes the social dimensions of the reception, transmission, and uptake of scientific knowledge in society and the ways in which social forces influence both positively and negatively the trustworthiness of science.

Risk-Perception Change Associated with COVID-19 Vaccine's Side Effects: The Role of Individual Differences

The COVID-19 vaccine appears to be a crucial requirement to fight the pandemic. However, a part of the population possesses negative attitudes towards the vaccine. The spread of conspiracy theories and contradictory information about the pandemic have altered the population’s perception of risk. The risk-perception of the vaccine’s side effects may be affected by individual differences. The complex relationship between risk-perception and individual differences is relevant when people have to make decisions based on ambiguous and constantly changing information, as in the early phases of the Italian vaccination campaign. The present study aimed at measuring the effect of individual differences in risk-perception associated with the COVID-19 vaccine’s side effects in a context characterized by information ambiguity. An online survey was conducted to classify a sample of Italian pro-vaccine people into cognitive/behavioral style groups. Furthermore, changes in vaccine risk-perception after inconsistent communications regarding the vaccine’s side effects were compared between groups. The results showed that “analytical” individuals did not change their perception regarding the probability of vaccine side effects but changed their perception regarding the severity of side effects; “open” and “polarized” individuals neither changed their perception regarding the probability nor of the severity of side effects, showing a different kind of information processing, which could interfere with an informed decision-making process.

COVID-19 Vaccine Hesitancy Among Deployed Personnel in a Joint Environment

INTRODUCTION

In the United States, vaccine hesitancy has been identified as a major barrier to vaccination against COVID-19, but attitudes toward COVID-19 vaccination among military personnel are not well understood. We evaluated the prevalence and correlates of COVID-19 vaccine consent or refusal among deployed personnel in a joint environment.

MATERIALS AND METHODS

Deidentified data were retrospectively extracted from the electronic medical record of the Military Health System in May 2021. All personnel currently assigned to the deployment area of operations were included in the analysis if their choice to receive the vaccine was known. Personnel characteristics were compared by vaccine acceptance status using chi-square tests, Fisher's exact tests, or correlation coefficients. This analysis was exempted from Institutional Review Board review.

RESULTS

The sample included 1,809 individuals, primarily members of the Army (72%) and members of Reserve (53%) or National Guard (27%) units. In the overall sample, 61% accepted the vaccine, with vaccine acceptance rates being lowest among Black or African American personnel (54%; P = .03 for comparison across racial groups) and members of Reserve or National Guard units (59%; P < .001 for comparison by component). No differences in vaccine acceptance were found according to sex or health status (including prior COVID-19 infection).

CONCLUSIONS

Overall vaccine acceptance was greater among deployed military personnel than that reported in the U.S. population as a whole. However, lower vaccine acceptance among personnel from marginalized populations suggests a need to ensure that all service members have sufficient opportunities to have a frank and ongoing discussion with health care providers to address concerns related to vaccination. Additionally, lower vaccine acceptance among Reserve and National Guard personnel indicates a need for innovative educational approaches to counter vaccine hesitancy in the premobilization phase of deployment.

Vaccinating against COVID-19: The Correlation between Pro-Vaccination Attitudes and the Belief That Our Peers Want to Get Vaccinated

This study verifies whether there is a strong correlation between the pro-vaccination, against COVID-19 attitude of the respondents and their belief that most of those around them want to be vaccinated against COVID-19. For this purpose, we analyzed data from a sociological survey conducted in April 2021 in Romania. The sample size was of 1001 respondents, the selection process was randomized and the population included in the sample is representative of the socio-demographic structure of Romania. The tool used to collect the data was CATI (telephonic interview). In order to test the existence of these correlations we performed the following tests: Chi-Square test, Kendall τ, Spearman ρ tests and Freeman's z-test. The pro-vaccination attitude strongly correlates with the perception of subjects that their primary group accepts vaccination and even correlates with the perception that the general public is rather pro-vaccination. The vaccination decision is closely linked to the social relations system and the rules of the community in which the subject lives. In this paper we discuss the correlation between attitude and belief, not the existence of a causal relation between the two of them.

SARS-CoV-2 Transmission and Impacts of Unvaccinated-Only Screening in Populations of Mixed Vaccination Status.. [PMID: 34909778 PMCID: PMC8669845 DOI: 10.1101/2021.10.19.21265231]

Community testing programs focused on the unvaccinated population are being enacted in populations with mixed vaccination status to mitigate SARS-CoV-2 spread. Presumably, these policies assume that the unvaccinated are driving transmission, though it is not well understood how viral spread occurs in mixed-status populations. Here, we analyze a model of transmission in which a variable fraction of the population is vaccinated, with unvaccinated individuals proactively screened for infection. By exploring a range of transmission rates, vaccine effectiveness (VE) scenarios, and rates of prior infection, this analysis reveals principles of viral spread in communities of mixed vaccination status, with implications for screening policies. As vaccination rates increase, the proportion of transmission driven by the unvaccinated population decreases, such that most community spread is driven by breakthrough infections once vaccine coverage exceeds 55% (omicron) or 80% (delta), with additional variation dependent on waning or boosted VE. More broadly, the potential impacts of unvaccinated-only screening fall into three distinct parameter regions: (I) “flattening the curve” with little impact on cumulative infections, (II) effectively suppressing transmission, and (III) negligible impact because herd immunity is reached without screening. By evaluating a wide range of scenarios, this work finds broadly that effective mitigation of SARS-CoV-2 transmission by unvaccinated-only screening is highly dependent on vaccination rate, population-level immunity, screening compliance, and vaccine effectiveness against the current variant.

Healthcare Providers' Vaccine Perceptions, Hesitancy, and Recommendation to Patients: A Systematic Review

Despite vaccines' effectiveness in reducing the rate of preventable diseases, vaccine hesitancy has threatened public health and economies worldwide. Healthcare providers' (HCP) communications and behavior strongly influence patient receptivity and uptake. The goal of this review was to examine HCP vaccine perceptions, knowledge, and reservations and how these attitudes affect their recommendations and vaccination practices. Primary research studies published by 16 September 2020 were searched in PubMed, Web of Science, Embase, CINAHL, and PsycINFO. A 14-item scale was developed for survey study and risk of bias appraisal (SSRBA). In total, 96 papers from 34 countries were included, covering 17 vaccines (HPV and influenza vaccines the most studied). Recommendation was positively associated with provider knowledge and experience, beliefs about disease risk, and perceptions of vaccine safety, necessity, and efficacy. HCP vaccination attitudes and practices varied across specialties, vaccines, and countries; demographic impact was inconclusive. Barriers included anticipation of patient/parental concerns or refusal, lacking clear guidelines, time constraints, and cost. For HPV, vaccines were more often recommended to older, female adolescents and by physicians who discussed sexual health. HCPs are vital advocates for patients and the public, but studies indicated a prevalence of provider hesitancy pertaining to inadequate knowledge, low vaccine confidence, and suboptimal uptake themselves. Improving HCP knowledge and assuring their access to information they deem trustworthy are essential to supporting HCPs' role as "trusted messengers" to promote vaccine acceptance.