COVID-19 vaccine intentions in the United States,a social-ecological framework

BackgroundCOVID-19 vaccine hesitancy is a major obstacle for pandemic mitigation. As vaccine hesitancy occurs along multiple dimensions, we used a social-ecological framework to guide the examination of COVID-19 vaccine intentions.MethodsUsing an online survey in the US conducted in July 2020, we examined intentions to obtain a COVID-19 vaccine, once available. 592 respondents provided data, including measures of demographics, vaccine history, social norms, perceived risk, and trust in sources of COVID-19 information. Bivariate and multivariate multinomial models were used to compare respondents who intended to be vaccinated against COVID-19 to respondents who did not intend or were ambivalent about COVID-19 vaccination.ResultsOnly 59.1% of the sample reported that they intended to obtain a COVID-19 vaccine. In the multivariate multinomial model, those respondents who did not intend to be vaccinated, as compared to those who did, had significantly lower levels of trust in the CDC as a source of COVID-19 information (aOR = 0.29, CI = 0.17–0.50), reported lower social norms of COVID-19 preventive behaviors (aOR = 0.67, CI 0.51–0.88), scored higher on COVID-19 Skepticism (aOR = 1.44, CI = 1.28–1.61), identified as more politically conservative (aOR = 1.23, CI = 1.05–1.45), were less likely to have obtained a flu vaccine in the prior year (aOR = 0.21, CI = 0.11–0.39), were less likely to be female (aOR = 0.51, CI = 0.29–0.87), and were much more likely to be Black compared to White (aOR = 10.70, CI = 4.09–28.1). A highly similar pattern was observed among those who were ambivalent about receiving a COVID-19 vaccine compared to those who intended to receive one.ConclusionThe results of this study suggest several avenues for COVID-19 vaccine promotion campaigns, including social network diffusion strategies and cross-partisan messaging, to promote vaccine trust. The racial and gender differences in vaccine intentions also suggest the need to tailor campaigns based on gender and race.     

新型冠状病毒肺炎疫情期间公众口罩使用情况和基本防护意识分析

目的 调查新冠肺炎疫情期间公众口罩使用和认知情况及疫情基本防护意识,为今后疫情健康教育工作提供依据.方法 采用网络调查法,在“广东痰控”微信公众号发布问卷,以自行设计的调查表做自填式问卷调查.收集基本信息、口罩使用情况及防护信息,采用描述性方法和Logistic回归分别对公众口罩使用情况及新冠疫情防护意识强度的影响因素...     

Transmission dynamics of COVID-19 in Algeria: The impact of physical distancing and face masks

We propose an SIR epidemic model taking into account prevention measures against coronavirus disease 2019 (COVID-19) such as wearing masks and respecting safety distances. We look for the conditions to avoid a second epidemic peak in the phase of release from confinement. We derive equations for the critical levels of mask efficiency, mask adoption (fraction of population wearing masks) and fraction of population engaging in physical distancing that lower the basic reproduction number ℜ₀ to unity. Conclusions: For ℜ₀ = 2.5, if at least 40% of people wear masks with efficiency 50%, and at least 20% of the population without masks (or anti-maskers) respect physical distancing measures, the effective reproduction number can be reduced to less than 1 and COVID-19 infections would plummet. The model predicts also that if at least half of the people respecting physical distancing, COVID-19 outbreaks with ℜ₀ of about 3, would be theoretically extinguished without wearing masks. The results of this study provide an alternative explanation for the spread of the disease, and suggest some valuable policy recommendations about the control strategies applied to mitigate disease transmission.     

COVID-19 vaccine hesitancy cannot fully explain disparities in vaccination coverage across the contiguous United States

Vaccine hesitancy has been identified as a major obstacle preventing comprehensive coverage against the COVID-19 pandemic. However, few studies have analyzed the association between ex-ante vaccine hesitancy and ex-post vaccination coverage. This study leveraged one-year county-level data across the contiguous United States to examine whether the prospective vaccine hesitancy eventually translates into differential vaccination rates, and whether vaccine hesitancy can explain socioeconomic, racial, and partisan disparities in vaccine uptake. A set of structural equation modeling was fitted with vaccine hesitancy and vaccination rate as endogenous variables, controlling for various potential confounders. The results demonstrated a significant negative link between vaccine hesitancy and vaccination rate, with the difference between the two continuously widening over time. Counties with higher socioeconomic statuses, more Asian and Hispanic populations, more elderly residents, greater health insurance coverage, and more Democrats presented lower vaccine hesitancy and higher vaccination rates. However, underlying determinants of vaccination coverage and vaccine hesitancy were divergent regarding their different associations with exogenous variables. Mediation analysis further demonstrated that indirect effects from exogenous variables to vaccination coverage via vaccine hesitancy only partially explained corresponding total effects, challenging the popular narrative that portrays vaccine hesitancy as a root cause of disparities in vaccination. Our study highlights the need of well-funded, targeted, and ongoing initiatives to reduce persisting vaccination inequities.     

Comparison of test-negative and syndrome-negative controls in SARS-CoV-2 vaccine effectiveness evaluations for preventing COVID-19 hospitalizations in the United States

BackgroundTest-negative design (TND) studies have produced validated estimates of vaccine effectiveness (VE) for influenza vaccine studies. However, syndrome-negative controls have been proposed for differentiating bias and true estimates in VE evaluations for COVID-19. To understand the use of alternative control groups, we compared characteristics and VE estimates of syndrome-negative and test-negative VE controls.MethodsAdults hospitalized at 21 medical centers in 18 states March 11–August 31, 2021 were eligible for analysis. Case patients had symptomatic acute respiratory infection (ARI) and tested positive for SARS-CoV-2. Control groups were test-negative patients with ARI but negative SARS-CoV-2 testing, and syndrome-negative controls were without ARI and negative SARS-CoV-2 testing. Chi square and Wilcoxon rank sum tests were used to detect differences in baseline characteristics. VE against COVID-19 hospitalization was calculated using logistic regression comparing adjusted odds of prior mRNA vaccination between cases hospitalized with COVID-19 and each control group.Results5811 adults (2726 cases, 1696 test-negative controls, and 1389 syndrome-negative controls) were included. Control groups differed across characteristics including age, race/ethnicity, employment, previous hospitalizations, medical conditions, and immunosuppression. However, control-group-specific VE estimates were very similar. Among immunocompetent patients aged 18–64 years, VE was 93 % (95 % CI: 90–94) using syndrome-negative controls and 91 % (95 % CI: 88–93) using test-negative controls.ConclusionsDespite demographic and clinical differences between control groups, the use of either control group produced similar VE estimates across age groups and immunosuppression status. These findings support the use of test-negative controls and increase confidence in COVID-19 VE estimates produced by test-negative design studies.     

Evaluation of post-introduction COVID-19 vaccine effectiveness: Summary of interim guidance of the World Health Organization

Phase 3 randomized-controlled trials have provided promising results of COVID-19 vaccine efficacy, ranging from 50 to 95% against symptomatic disease as the primary endpoints, resulting in emergency use authorization/listing for several vaccines. However, given the short duration of follow-up during the clinical trials, strict eligibility criteria, emerging variants of concern, and the changing epidemiology of the pandemic, many questions still remain unanswered regarding vaccine performance. Post-introduction vaccine effectiveness evaluations can help us to understand the vaccine's effect on reducing infection and disease when used in real-world conditions. They can also address important questions that were either not studied or were incompletely studied in the trials and that will inform evolving vaccine policy, including assessment of the duration of effectiveness; effectiveness in key subpopulations, such as the very old or immunocompromised; against severe disease and death due to COVID-19; against emerging SARS-CoV-2 variants of concern; and with different vaccination schedules, such as number of doses and varying dosing intervals. WHO convened an expert panel to develop interim best practice guidance for COVID-19 vaccine effectiveness evaluations. We present a summary of the interim guidance, including discussion of different study designs, priority outcomes to evaluate, potential biases, existing surveillance platforms that can be used, and recommendations for reporting results.     

Effect of the suspension of the J&J COVID-19 vaccine on vaccine hesitancy in the United States

On April 13, 2021, U.S. authorities announced an investigation into potential adverse events associated with the Johnson & Johnson (Janssen, J&J) COVID-19 vaccine and recommended “a pause in the use of this vaccine out of an abundance of caution.” We examined whether public attitudes toward COVID-19 vaccination shifted after this recommended suspension using an interrupted time series with data from the Census Bureau’s Household Pulse Survey, which was fielded bi-weekly between January 6 and April 26, 2021. We found no significant changes in trends of the proportion of the U.S. adult population hesitant about getting a COVID-19 vaccine, but a significant increase in concerns about safety and efficacy of COVID-19 vaccines among the already hesitant population.     

A historical analysis of vaccine mandates in the United States military and its application to the COVID-19 vaccine mandate

The Department of Defense has implemented a mandate that all military personnel be vaccinated against COVID-19. This article reviews the historical precedent of vaccine mandates for United States military personnel dating back to the formation of the continental army, as well as previous controversies about vaccine mandates such as the first influenza vaccine mandate and the Anthrax Vaccine Immunization Program. The historical review discusses precedent for the current COVID-19 vaccine mandate and the reception of these vaccine mandates by military personnel. The review then discusses how these historical lessons can inform the present COVID-19 vaccine mandate.     

Marketing the COVID-19 vaccine and the implications for public health

COVID-19 vaccines are new brands of consumer health technology being introduced to the market. Considering consumer behaviour approaches in this time of crisis, the risk of vaccine hesitancy, the call for more transparency and effective messaging to gain trust, and equitable distribution of this vaccine, this is unexplored theoretical terrain. This commentary takes a multidisciplinary approach to understand and theoretically explore the marketing, distribution, and acceptance of the COVID-19 vaccine. The paper integrates marketing principles, including advertisement and branding of consumer health technology with supply chain management, public affairs, and public health. A theoretical framework was presented to illustrate this relationship and key areas of concerns. The practical implications relevant to equity, ethics, education, employment, and the economic impact was presented.     

Factors associated with receipt of mRNA-1273 vaccine at a United States national retail pharmacy during the COVID-19 pandemic

IntroductionThe emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prompted accelerated vaccine development of novel messenger RNA (mRNA)-based vaccines by Moderna and Pfizer, which received FDA Emergency Use Authorization in December 2020. The purpose of this study was to examine trends in primary series administration and multi-dose completion rates with Moderna’s mRNA-1273 vaccine administered at a United States retail pharmacy.MethodsWalgreens pharmacy data were joined to publicly available data sets to examine trends in mRNA-1273 primary series and multi-dose completion across patient race/ethnicity, age, gender, distance to first vaccination, and community characteristics. Eligible patients received their first dose of mRNA-1273 administered by Walgreens between December 18, 2020 and February 28, 2022. Variables significantly associated with on-time second dose (all patients) and third dose (immunocompromised patients) in univariate analyses were included in linear regression models. A subset of patients in selected states were studied to identify differences in early and late vaccine adoption.ResultsPatients (N = 4,870,915) who received ≥ 1 dose of mRNA-1273 were 57.0% White, 52.6% female, and averaged 49.4 years old. Approximately 85% of patients received a second dose during the study period. Factors associated with on-time second dose administration included older age, race/ethnicity, traveling ≤ 10 miles for the first dose, higher community-level health insurance, and residing in areas with low social vulnerability. Only 51.0% of immunocompromised patients received the third dose as recommended. Factors associated with third dose administration included older age, race/ethnicity, and small-town residence. Early adopters accounted for 60.6% of patients. Factors associated with early adoption included older age, race/ethnicity, and metropolitan residence.ConclusionOver 80% of patients received their on-time second dose of mRNA-1273 vaccine per CDC recommendations. Patient demographics and community characteristics were associated with vaccine receipt and series completion. Novel approaches to facilitate series completion during a pandemic should be further studied.     

Assessing vaccine effectiveness against severe COVID-19 disease caused by omicron variant. Report from a meeting of the World Health Organization

Vaccine effectiveness is lower and wanes faster against infection and symptomatic disease caused by the omicron variant of SARS-CoV-2 than was observed with previous variants. Vaccine effectiveness against severe omicron disease, on average, is higher, but has shown variability, including rapid apparent waning, in some studies. Assessing vaccine effectiveness against omicron severe disease using hospital admission as a measure of severe disease has become more challenging because of omicron’s attenuated intrinsic severity and its high prevalence of infection. Many hospital admissions likely occur among people with incidental omicron infection or among those with infection-induced exacerbation of chronic medical conditions. To address this challenge, the World Health Organization held a virtual meeting on March 15, 2022, to review evidence from several studies that assessed Covid-19 vaccine effectiveness against severe omicron disease using several outcome definitions. Data was shown from studies in South Africa, the United States, the United Kingdom and Qatar. Several approaches were proposed that better characterize vaccine protection against severe Covid-19 disease caused by the omicron variant than using hospitalization of omicron-infected persons to define severe disease. Using more specific definitions for severe respiratory Covid-19 disease, such as indicators of respiratory distress (e.g. oxygen requirement, mechanical ventilation, and ICU admission), showed higher vaccine effectiveness than against hospital admission. Second, vaccine effectiveness against progression from omicron infection to hospitalization, or severe disease, also showed higher vaccine protection. These approaches might better characterize vaccine performance against severe Covid-19 disease caused by omicron, as well as future variants that evade humoral immunity, than using hospitalization with omicron infection as an indicator of severe disease.     

A cross-sectional analysis of the association between social capital and willingness to get COVID-19 vaccine in Ontario,Canada

ObjectiveWe examine the role of social capital in intention to take the vaccine at the end of the first wave of the COVID-19 pandemic.MethodsThis study uses observational, cross-sectional data from the Ontario sample of the fall 2020 Canadian Community Health Survey (CCHS), a representative sample of the population with added questions relative to symptoms of COVID-19 and intentions to get vaccinated. Questions on social capital were asked to respondents from Ontario only, yielding a sample of 6516. Odds ratios (OR) and marginal effects at sample mean of an index of social capital (at the individual or aggregated level) on changes in intentions to get vaccinated are estimated from logistic regression models.ResultsIndividual-level social capital is associated with greater willingness to get vaccinated against COVID-19 (OR 1.09). Associations with aggregated-level social capital are less precisely estimated. Associations are the same for both males and females but vary across age categories: individual-level social capital is associated with higher willingness to get vaccinated among working-age respondents, but aggregate-level social capital is associated with higher willingness to get vaccinated among older adults.ConclusionVaccine hesitancy is not a random phenomenon, nor is it explained by individual characteristics such as education or income only. It also reflects the state of the social environment in which individuals live and public health messaging should take this into account if it is to be successful.Supplementary InformationThe online version contains supplementary material available at 10.17269/s41997-023-00746-9.     

Geo-prioritization framework for COVID-19 vaccine allocation in India

Up until now, countries have adopted a ‘isolate-test-treat-trace’ strategy to contain the COVID-19 pandemic. The next critical intervention in the fight against COVID-19 will be effective delivery of safe and efficacious vaccines. Various countries such as the USA, the UK, Canada, Israel, etc., have started administering vaccines to priority population groups. India is gearing up its critical components of the vaccine delivery system to effectively deliver vaccines across the country and has prioritized certain population groups to whom the vaccine will be administered. Considering India’s ambitious target to vaccinate close to 300 million people in the first phase of the vaccination drive with limited initial supply (which will be ramped up gradually), it is critical for stakeholders at all the levels – national, state and district – to understand the estimated need for vaccines across geographies based on the vulnerable population and disease epidemiology with the objective of preventing maximum number of future infections from the disease. This paper aims to describe a comprehensive geo-prioritization framework based on existing prevalence of COVID-19, high-risk co-morbidities, and demographic analysis to identify states/districts that could be most in need of the COVID-19 vaccines.     

Trends in effectiveness of inactivated influenza vaccine in children by age groups in seven seasons immediately before the COVID-19 era

BackgroundWe have reported the vaccine effectiveness of inactivated influenza vaccine in children aged 6 months to 15 years between the 2013/14 and 2018/19 seasons. Younger (6–11 months) and older (6–15 years old) children tended to have lower vaccine effectiveness. The purpose of this study is to investigate whether the recent vaccine can be recommended to all age groups.MethodsThe overall adjusted vaccine effectiveness was assessed from the 2013/14 until the 2020/21 season using a test-negative case-control design based on rapid influenza diagnostic test results. Vaccine effectiveness was calculated by influenza type and by age group (6–11 months, 1–2, 3–5, 6–12, and 13–15 years old) with adjustments including influenza seasons.ResultsA total of 29,400 children (9347, 4435, and 15,618 for influenza A and B, and test-negatives, respectively) were enrolled. The overall vaccine effectiveness against influenza A, A(H1N1)pdm09, and B was significant (44% [95% confidence interval (CI), 41–47], 63% [95 %CI, 51–72], and 37% [95 %CI, 32–42], respectively). The vaccine was significantly effective against influenza A and B, except among children 6 to 11 months against influenza B. The age group with the highest vaccine effectiveness was 1 to 2 years old with both influenza A and B (60% [95 %CI, 55–65] and 52% [95 %CI, 41–61], respectively). Analysis for the 2020/21 season was not performed because no cases were reported.ConclusionsThis is the first report showing influenza vaccine effectiveness by age group in children for several seasons, including immediately before the coronavirus disease (COVID-19) era. The fact that significant vaccine effectiveness was observed in nearly every age group and every season shows that the recent vaccine can still be recommended to children for the upcoming influenza seasons, during and after the COVID-19 era.     

U.S. public support for COVID-19 vaccine donation to low- and middle-income countries during the COVID-19 pandemic

As COVID-19 vaccines become available to the public, there will be a massive worldwide distribution effort. Vaccine distribution has historically been unequal primarily due to the inability of nations with developing economies to purchase enough vaccine to fully vaccinate their populations. Inequitable access to COVID-19 vaccines will not just cause humanitarian suffering, it will likely also be associated with increased economic suffering worldwide. This study focuses on the U.S. population and its beliefs about future COVID-19 vaccine donation by the U.S. to low- and middle-income countries.This study carried out a survey among 788 U.S. adults. Variables include demographics, COVID-19 vaccine priority status, COVID-19 vaccine donation beliefs, and Social Dominance Orientation.Analyses showed that older respondents were both less likely to endorse higher levels of COVID-19 vaccine donations and were more likely to want to wait until all in the U.S. who want the vaccine have received it; those who identified as Democrats were more likely to endorse higher levels of future COVID-19 vaccine donation than Republicans; and those scoring higher on SDO were both less likely to endorse higher levels of COVID-19 vaccine donations as well as more likely to want to wait until all in the U.S. who want the vaccine have received it. Policymakers, as well as healthcare providers and public health communication professionals, should give consideration to those messages most likely to engender support for global prevention efforts with each audience segment.     

A log-odds system for waning and boosting of COVID-19 vaccine effectiveness

Immunity to SARS-CoV-2 following vaccination wanes over time in a non-linear fashion, making modelling of likely population impacts of COVID-19 policy options challenging. We observed that it was possible to mathematize non-linear waning of vaccine effectiveness (VE) on the percentage scale as linear waning on the log-odds scale, and developed a random effects logistic regression equation based on UK Health Security Agency data to model VE against Omicron following two and three doses of a COVID-19 vaccine. VE on the odds scale reduced by 47% per month for symptomatic infection after two vaccine doses, lessening to 35% per month for hospitalisation. Waning on the odds scale after triple dose vaccines was 35% per month for symptomatic disease and 19% for hospitalisation. This log-odds system for estimating waning and boosting of COVID-19 VE provides a simple solution that may be used to parametrize SARS-CoV-2 immunity over time parsimoniously in epidemiological models.     

Protection motivation unmasked: Applying protection motivation theory to skepticism toward COVID-19 mask and vaccine mandates

Variants of COVID-19 have sparked controversy regarding mask and/or vaccine mandates in some sectors of the country. Many people hold polarized opinions about such mandates, and it is uncertain what predicts attitudes towards these protective behavior mandates. Through a snow-ball sampling procedure of respondents on social media platforms, this study examined skepticism of 774 respondents toward these mandates as a function of the Protection Motivation Theory (PMT) of health. Hierarchical linear regressions examined Protection Motivation (PM) as a predictor of mask and vaccine mandate skepticism independently and with political party affiliation as a control. PM alone accounted for 76% of the variance in mask mandate skepticism, p < 0.001 and 65% in vaccine mandate skepticism, p < 0.001. When political affiliation was entered (accounting for 28% of the variance in mask mandate skepticism, p < 0.001, and 26% in vaccine mandate skepticism, p < 0.001), PM still accounted for significant percentages of variance in both mask (50%) and vaccine (43%) mandate skepticism, ps < 0.001. Across regressions, perceived severity, outcome efficaciousness, and self-efficacy each directly accounted for unique variance in mask and vaccine mandate skepticism, ps < 0.001; only perceived vulnerability failed to account for unique variance in the regressions, ps > 0.05. Specifically, the more severe participants perceived COVID-19 to be and the greater the perceived efficacy of masks and vaccines preventing the spread of COVID-19, the lower participants'' skepticism toward mask and vaccine mandates. Similarly, the higher participants'' self-efficacy in wearing masks or receiving the vaccine, the lower their skepticism toward mask and vaccine mandates.