Behavioral and social drivers of COVID-19 vaccination initiation in the US: a longitudinal study March─ October 2021.

Many studies have examined behavioral and social drivers of COVID-19 vaccination initiation, but few have examined these drivers longitudinally. We sought to identify the drivers of COVID-19 vaccination initiation using the Behavioral and Social Drivers of Vaccination (BeSD) Framework. Participants were a nationally-representative sample of 1,563 US adults who had not received a COVID-19 vaccine by baseline. Participants took surveys online at baseline (spring 2021) and follow-up (fall 2021). The surveys assessed variables from BeSD Framework domains (i.e., thinking and feeling, social processes, and practical issues), COVID-19 vaccination initiation, and demographics at baseline and follow-up. Between baseline and follow-up, 65% of respondents reported initiating COVID-19 vaccination. Vaccination intent increased from baseline to follow-up (p < .01). Higher vaccine confidence, more positive social norms towards vaccination, and receiving vaccine recommendations at baseline predicted subsequent COVID-19 vaccine initiation (all p < .01). Among factors assessed at follow-up, social responsibility and vaccine requirements had the greatest associations with vaccine initiation (all p < .01). Baseline vaccine confidence, social norms, and vaccination recommendations were associated with subsequent vaccine initiation, all of which could be useful targets for behavioral interventions. Furthermore, interventions that highlight social responsibility to vaccinate or promote vaccination requirements could also be beneficial.

Strengthening COVID-19 vaccine confidence & demand during the US COVID-19 emergency response.

In October 2020, the CDC's Vaccinate with Confidence strategy specific to COVID-19 vaccines rollout was published. Adapted from an existing vaccine confidence framework for childhood immunization, the Vaccinate with Confidence strategy for COVID-19 aimed to improve vaccine confidence, demand, and uptake of COVID-19 vaccines in the US. The objectives for COVID-19 were to 1. build trust, 2. empower healthcare personnel, and 3. engage communities and individuals. This strategy was implemented through a dedicated unit, the Vaccine Confidence and Demand (VCD) team, which collected behavioral insights; developed and disseminated toolkits and best practices in collaboration with partners; and collaborated with health departments and community-based organizations to engage communities and individuals in behavioral interventions to strengthen vaccine demand and increase COVID-19 vaccine uptake. The VCD team collected and used social and behavioral data through establishing the Insights Unit, implementing rapid community assessments, and conducting national surveys. To strengthen capacity at state and local levels, the VCD utilized "Bootcamps," a rapid training of trainers on vaccine confidence and demand, "Confidence Consults", where local leaders could request tailored advice to address local vaccine confidence challenges from subject matter experts, and utilized surge staffing to embed "Vaccine Demand Strategists" in state and local public health agencies. In addition, collaborations with Prevention Research Centers, the Institute of Museum and Library Services, and the American Psychological Association furthered work in behavioral science, community engagement, and health equity. The VCD team operationalized CDC's COVID-19 Vaccine with Confidence strategy through behavioral insights, capacity building opportunities, and collaborations to improve COVID-19 vaccine confidence, demand, and uptake in the US. The inclusion of applied behavioral science approaches were a critical component of the COVID-19 vaccination program and provides lessons learned for how behavioral science can be integrated in future emergency responses.

What motivates adults to accept influenza vaccine? An assessment of incentives, ease of access, messaging, and sources of information using a discrete choice experiment.

Seasonal influenza vaccination rates remain low, and contribute to preventable influenza cases, hospitalizations, and deaths in the US. While numerous interventions have been implemented to increase vaccine uptake, there is a need to determine which interventions contribute most to vaccine willingness, particularly among age groups with vaccination rates that have plateaued at suboptimal levels. This study aimed to quantify the relative effect of multiple interventions on vaccine willingness to receive influenza vaccine in three age groups using a series of hypothetical situations with different behavioral interventions. We assessed the relative impact of four categories of interventions: source of vaccine messages, type of vaccination messages, vaccination incentives, and ease of vaccine access using a discrete choice experiment. Within each category, we investigated the role of four different attributes to measure their relative contribution to willingness to be vaccinated by removing one option from each of the intervention categories. Among the 1,763 Minnesota residents who volunteered for our study, participants expressed vaccine willingness in over 80% of the scenarios presented. Easy access to drop-in vaccination sites had the greatest impact on vaccine willingness in all age groups. Among the younger age group, small financial incentives also contributed to high vaccine willingness. Our results suggest that public health programs and vaccination campaigns may improve their chances of successfully increasing vaccine willingness if they offer interventions preferred by adults, including facilitating convenient access to vaccination and offering small monetary incentives, particularly for young adults.

Behavioral and Social Drivers of COVID-19 Vaccination in the United States, August-November 2021.

INTRODUCTION: COVID-19 vaccines are safe, effective, and widely available, but many adults in the U.S. have not been vaccinated for COVID-19. This study examined the associations between behavioral and social drivers of vaccination with COVID-19 vaccine uptake in the U.S. adults and their prevalence by region. METHODS: A nationally representative sample of U.S. adults participated in a cross-sectional telephone survey in August-November 2021; the analysis was conducted in January 2022. Survey questions assessed self-reported COVID-19 vaccine initiation, demographics, and behavioral and social drivers of vaccination. RESULTS: Among the 255,763 respondents, 76% received their first dose of COVID-19 vaccine. Vaccine uptake was higher among respondents aged ≥75 years (94%), females (78%), and Asian non-Hispanic people (94%). The drivers of vaccination most strongly associated with uptake included higher anticipated regret from nonvaccination, risk perception, and confidence in vaccine safety and importance, followed by work- or school-related vaccination requirements, social norms, and provider recommendation (all p<0.05). The direction of association with uptake varied by reported level of difficulty in accessing vaccines. The prevalence of all of these behavioral and social drivers of vaccination was highest in the Northeast region and lowest in the Midwest and South. CONCLUSIONS: This nationally representative survey found that COVID-19 vaccine uptake was most strongly associated with greater anticipated regret, risk perception, and confidence in vaccine safety and importance, followed by vaccination requirements and social norms. Interventions that leverage these social and behavioral drivers of vaccination have the potential to increase COVID-19 vaccine uptake and could be considered for other vaccine introductions.

A qualitative study of behavioral and social drivers of COVID-19 vaccine confidence and uptake among unvaccinated Americans in the US April-May 2021.

INTRODUCTION: Around one-third of Americans reported they were unwilling to get a COVID-19 vaccine in April 2021. This focus group study aimed to provide insights on the factors contributing to unvaccinated adults' hesitancy or refusal to get vaccinated with COVID-19 vaccines. METHOD: Ipsos recruited 59 unvaccinated US adults who were vaccine hesitant (i.e., conflicted about or opposed to receiving a COVID-19 vaccination) using the Ipsos KnowledgePanel. Trained facilitators led a total of 10 focus groups via video-conference in March and April 2021. Two coders manually coded the data from each group using a coding frame based on the focus group discussion guide. The coding team collaborated in analyzing the data for key themes. RESULTS: Data analysis of transcripts from the focus groups illuminated four main themes associated with COVID-19 vaccine hesitancy: lack of trust in experts and institutions; concern about the safety of COVID-19 vaccines; resistance towards prescriptive guidance and restrictions; and, despite personal reluctance or unwillingness to get vaccinated, acceptance of others getting vaccinated. DISCUSSION: Vaccine confidence communication strategies should address individual concerns, describe the benefits of COVID-19 vaccination, and highlight evolving science using factural and neutral presentations of information to foster trust.

Explaining demographic differences in COVID-19 vaccination stage in the United States - April-May 2021.

COVID-19 vaccine coverage in the US has marked demographic and geographical disparities, but few explanations exist for them. Our paper aimed to identify behavioral and social drivers that explain these vaccination disparities. Participants were a national probability sample of 3562 American adults, recruited from the Ipsos KnowledgePanel. Participants completed an online survey in spring 2021, when COVD-19 vaccination was available for higher-risk groups but not yet available to all US adults. The survey assessed COVID-19 vaccination stage (intentions and vaccine uptake), constructs from the Increasing Vaccination Model (IVM) domains (thinking and feeling, social processes, and direct behavior change), self-reported exposure to COVID-19 vaccine information, and demographic characteristics. Analyses used multiple imputation to address item nonresponse and linear regressions to conduct mediation analyses. Higher COVID-19 vaccination stage was strongly associated with older age, liberal political ideology, and higher income in adjusted analyses (all p < .001). Vaccination stage was more modestly associated with urbanicity, white race, and Hispanic ethnicity (all p < .05). Some key mediators that explained more than one-third of demographic differences in vaccination stage were perceived vaccine effectiveness, social norms, and recommendations from family and friends across most demographic characteristics (all p < .05). Other mediators included safety concerns, trust, altruism, provider recommendation, and information seeking. Access to vaccination, barriers to vaccination, and self-efficacy explained few demographic differences. One of the most reliable explanations for demographic differences in COVID-19 vaccination stage is social processes, including social norms, recommendations, and altruism. Interventions to promote COVID-19 vaccination should address social processes and other domains in the IVM.

Case report: Persistent shedding of a live vaccine-derived rubella virus in a young man with severe combined immunodeficiency and cutaneous granuloma.

A young man with X-linked severe combined immunodeficiency developed a persistent vaccine-derived rubella virus (VDRV) infection, with the emergence of cutaneous granulomas more than fifteen years after receipt of two doses of measles-mumps-rubella (MMR) vaccine. Following nasopharyngeal swab (NP) collection, VDRV was detected by real-time polymerase chain reaction (RT-qPCR) and sequencing, and live, replication-competent VDRV was isolated in cell culture. To assess duration and intensity of viral shedding, sequential respiratory samples, one cerebrospinal fluid sample, and two urine samples were collected over 15 months, and VDRV RNA was detected in all samples by RT-qPCR. Live VDRV was cultured from nine of the eleven respiratory specimens and from one urine specimen. To our knowledge, this was the first reported instance of VDRV cultured from respiratory specimens or from urine. To assess potential transmission to close contacts, NP specimens and sera were collected from all household contacts, all of whom were immunocompetent and previously vaccinated with MMR. VDRV RNA was not detected in any NP swabs from the contacts, nor did serologic investigations suggest VDRV transmission to any contacts. This report highlights the need to understand the prevalence and duration of VDRV shedding in granuloma patients and to estimate the risk of VDRV transmission to immune and non-immune contacts.

Willingness to be vaccinated, preventative behaviors, and social contact patterns during the COVID-19 pandemic among US college students.

Objective: To assess the frequency of preventative COVID-19 behaviors and vaccination willingness among United States (US) college and university students during the COVID-19 pandemic. Participants: Participants (N = 653) were ≥18 years old and students at institutions for higher education in the US in March 2020. Methods: Students self-reported preventative behaviors, willingness to be vaccinated, and social contact patterns during four waves of online surveys from May-August 2020. Results: Student engagement in preventative behaviors was generally high. The majority of students intended to be vaccinated (81.5%). Overall, there were no significant differences in the proportion adopting preventative behaviors or in willingness to be vaccinated by sex or geographic location. The most common reason for willingness to get vaccinated was wanting to contribute to ending COVID-19 outbreaks (44.7%). Conclusions: Early in the pandemic, college students primarily reported willingness to vaccinate and adherence to preventative behaviors. Outreach strategies are needed to continue this momentum.

Employer requirements and COVID-19 vaccination and attitudes among healthcare personnel in the U.S.: Findings from National Immunization Survey Adult COVID Module, August - September 2021.

INTRODUCTION: Employer vaccination requirements have been used to increase vaccination uptake among healthcare personnel (HCP). In summer 2021, HCP were the group most likely to have employer requirements for COVID-19 vaccinations as healthcare facilities led the implementation of such requirements. This study examined the association between employer requirements and HCP's COVID-19 vaccination status and attitudes about the vaccine. METHODS: Participants were a national representative sample of United States (US) adults who completed the National Immunization Survey Adult COVID Module (NIS-ACM) during August-September 2021. Respondents were asked about COVID-19 vaccination and intent, requirements for vaccination, place of work, attitudes surrounding vaccinations, and sociodemographic variables. This analysis focused on HCP respondents. We first calculated the weighted proportion reporting COVID-19 vaccination for HCP by sociodemographic variables. Then we computed unadjusted and adjusted prevalence ratios for vaccination coverage and key indicators on vaccine attitudes, comparing HCP based on individual self-report of vaccination requirements. RESULTS: Of 12,875 HCP respondents, 41.5% reported COVID-19 vaccination employer requirements. Among HCP with vaccination requirements, 90.5% had been vaccinated against COVID-19, as compared to 73.3% of HCP without vaccination requirements-a pattern consistent across sociodemographic groups. Notably, the greatest differences in uptake between HCP with and without employee requirements were seen in sociodemographic subgroups with the lowest vaccination uptake, e.g., HCP aged 18-29 years, HCP with high school or less education, HCP living below poverty, and uninsured HCP. In every sociodemographic subgroup examined, vaccine uptake was more equitable among HCP with vaccination requirements than in HCP without. Finally, HCP with vaccination requirements were also more likely to express confidence in the vaccine's safety (68.3% vs. 60.1%) and importance (89.6% vs 79.6%). CONCLUSION: In a large national US sample, employer requirements were associated with higher and more equitable HCP vaccination uptake across all sociodemographic groups examined. Our findings suggest that employer requirements can contribute to improving COVID-19 vaccination coverage, similar to patterns seen for other vaccines.

What drives willingness to receive a new vaccine that prevents an emerging infectious disease? A discrete choice experiment among university students in Uganda.

BACKGROUND: There is a critical need to identify the drivers of willingness to receive new vaccines against emerging and epidemic diseases. A discrete choice experiment is the ideal approach to evaluating how individuals weigh multiple attributes simultaneously. We assessed the degree to which six attributes were associated with willingness to be vaccinated among university students in Uganda. METHODS: We conducted a single-profile discrete choice experiment at Makerere University in 2019. Participants were asked whether or not they would be vaccinated in 8 unique scenarios where attributes varied by disease risk, disease severity, advice for or against vaccination from trusted individuals, recommendations from influential figures, whether the vaccine induced indirect protection, and side effects. We calculated predicted probabilities of vaccination willingness using mixed logistic regression models, comparing health professional students with all other disciplines. FINDINGS: Of the 1576 participants, 783 (49.8%) were health professional students and 685 (43.5%) were female. Vaccination willingness was high (78%), and higher among health students than other students. We observed the highest vaccination willingness for the most severe disease outcomes and the greatest exposure risks, along with the Minister of Health's recommendation or a vaccine that extended secondary protection to others. Mild side effects and recommendations against vaccination diminished vaccination willingness. INTERPRETATION: Our results can be used to develop evidence-based messaging to encourage uptake for new vaccines. Future vaccination campaigns, such as for COVID-19 vaccines in development, should consider acknowledging individual risk of exposure and disease severity and incorporate recommendations from key health leaders.

COVID-19 Case Investigation and Contact Tracing in the US, 2020.

Importance: Contact tracing is a multistep process to limit SARS-CoV-2 transmission. Gaps in the process result in missed opportunities to prevent COVID-19. Objective: To quantify proportions of cases and their contacts reached by public health authorities and the amount of time needed to reach them and to compare the risk of a positive COVID-19 test result between contacts and the general public during 4-week assessment periods. Design, Setting, and Participants: This cross-sectional study took place at 13 health departments and 1 Indian Health Service Unit in 11 states and 1 tribal nation. Participants included all individuals with laboratory-confirmed COVID-19 and their named contacts. Local COVID-19 surveillance data were used to determine the numbers of persons reported to have laboratory-confirmed COVID-19 who were interviewed and named contacts between June and October 2020. Main Outcomes and Measures: For contacts, the numbers who were identified, notified of their exposure, and agreed to monitoring were calculated. The median time from index case specimen collection to contact notification was calculated, as were numbers of named contacts subsequently notified of their exposure and monitored. The prevalence of a positive SARS-CoV-2 test among named and tested contacts was compared with that jurisdiction's general population during the same 4 weeks. Results: The total number of cases reported was 74 185. Of these, 43 931 (59%) were interviewed, and 24 705 (33%) named any contacts. Among the 74 839 named contacts, 53 314 (71%) were notified of their exposure, and 34 345 (46%) agreed to monitoring. A mean of 0.7 contacts were reached by telephone by public health authorities, and only 0.5 contacts per case were monitored. In general, health departments reporting large case counts during the assessment (≥5000) conducted smaller proportions of case interviews and contact notifications. In 9 locations, the median time from specimen collection to contact notification was 6 days or less. In 6 of 8 locations with population comparison data, positive test prevalence was higher among named contacts than the general population. Conclusions and Relevance: In this cross-sectional study of US local COVID-19 surveillance data, testing named contacts was a high-yield activity for case finding. However, this assessment suggests that contact tracing had suboptimal impact on SARS-CoV-2 transmission, largely because 2 of 3 cases were either not reached for interview or named no contacts when interviewed. These findings are relevant to decisions regarding the allocation of public health resources among the various prevention strategies and for the prioritization of case investigations and contact tracing efforts.

Mosquito larval source management for controlling malaria.

BACKGROUND: Malaria is an important cause of illness and death in people living in many parts of the world, especially sub-Saharan Africa. Long-lasting insecticide treated bed nets (LLINs) and indoor residual spraying (IRS) reduce malaria transmission by targeting the adult mosquito vector and are key components of malaria control programmes. However, mosquito numbers may also be reduced by larval source management (LSM), which targets mosquito larvae as they mature in aquatic habitats. This is conducted by permanently or temporarily reducing the availability of larval habitats (habitat modification and habitat manipulation), or by adding substances to standing water that either kill or inhibit the development of larvae (larviciding). OBJECTIVES: To evaluate the effectiveness of mosquito LSM for preventing malaria. SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CABS Abstracts; and LILACS up to 24 October 2012. We handsearched the Tropical Diseases Bulletin from 1900 to 2010, the archives of the World Health Organization (up to 11 February 2011), and the literature database of the Armed Forces Pest Management Board (up to 2 March 2011). We also contacted colleagues in the field for relevant articles. SELECTION CRITERIA: We included cluster randomized controlled trials (cluster-RCTs), controlled before-and-after trials with at least one year of baseline data, and randomized cross-over trials that compared LSM with no LSM for malaria control. We excluded trials that evaluated biological control of anopheline mosquitoes with larvivorous fish. DATA COLLECTION AND ANALYSIS: At least two authors assessed each trial for eligibility. We extracted data and at least two authors independently determined the risk of bias in the included studies. We resolved all disagreements through discussion with a third author. We analyzed the data using Review Manager 5 software. MAIN RESULTS: We included 13 studies; four cluster-RCTs, eight controlled before-and-after trials, and one randomized cross-over trial. The included studies evaluated habitat modification (one study), habitat modification with larviciding (two studies), habitat manipulation (one study), habitat manipulation plus larviciding (two studies), or larviciding alone (seven studies) in a wide variety of habitats and countries. Malaria incidenceIn two cluster-RCTs undertaken in Sri Lanka, larviciding of abandoned mines, streams, irrigation ditches, and rice paddies reduced malaria incidence by around three-quarters compared to the control (RR 0.26, 95% CI 0.22 to 0.31, 20,124 participants, two trials, moderate quality evidence). In three controlled before-and-after trials in urban and rural India and rural Kenya, results were inconsistent (98,233 participants, three trials, very low quality evidence). In one trial in urban India, the removal of domestic water containers together with weekly larviciding of canals and stagnant pools reduced malaria incidence by three quarters. In one trial in rural India and one trial in rural Kenya, malaria incidence was higher at baseline in intervention areas than in controls. However dam construction in India, and larviciding of streams and swamps in Kenya, reduced malaria incidence to levels similar to the control areas. In one additional randomized cross-over trial in the flood plains of the Gambia River, where larval habitats were extensive and ill-defined, larviciding by ground teams did not result in a statistically significant reduction in malaria incidence (2039 participants, one trial). Parasite prevalenceIn one cluster-RCT from Sri Lanka, larviciding reduced parasite prevalence by almost 90% (RR 0.11, 95% CI 0.05 to 0.22, 2963 participants, one trial, moderate quality evidence). In five controlled before-and-after trials in Greece, India, the Philippines, and Tanzania, LSM resulted in an average reduction in parasite prevalence of around two-thirds (RR 0.32, 95% CI 0.19 to 0.55, 8041 participants, five trials, moderate quality evidence). The interventions in these five trials included dam construction to reduce larval habitats, flushing of streams, removal of domestic water containers, and larviciding. In the randomized cross-over trial in the flood plains of the Gambia River, larviciding by ground teams did not significantly reduce parasite prevalence (2039 participants, one trial). AUTHORS' CONCLUSIONS: In Africa and Asia, LSM is another policy option, alongside LLINs and IRS, for reducing malaria morbidity in both urban and rural areas where a sufficient proportion of larval habitats can be targeted. Further research is needed to evaluate whether LSM is appropriate or feasible in parts of rural Africa where larval habitats are more extensive.