Differential Effect of Vaccine Effectiveness and Safety on COVID-19 Vaccine Acceptance across Socioeconomic Groups in an International Sample

COVID-19 vaccination preferences during a pause in Johnson & Johnson vaccine administration

In April 2021, the US paused Janssen (J&J) COVID-19 vaccination because of reported blood clots post vaccination. This paper explores how vaccine decision-making--receiving a J&J vaccine right away vs waiting for a Pfizer vaccine--changed during the pause. In an opt-in internet-based survey April 2021 with 915 participants, 37 % were not vaccinated. Of these, 18 % would accept a J&J vaccine, 5 % would wait 1 month for a Pfizer vaccine, 25 % would wait 3 months, and 52 % would not want any vaccine. Among the unvaccinated, 56 % had heard of blood clots; 61 % of these did not want any vaccine, compared to 41 % of those who had not heard of blood clots. Moreover, among those vaccine hesitant in general, 11 % would still obtain a J&J vaccine if offered right away. These findings may suggest spillover of brand-specific adverse event concerns to the vaccine product as a whole.

Can psychological distress account for the associations between COVID-19 vaccination acceptance and socio-economic vulnerability?

Socially disadvantaged individuals and communities consistently showed lower COVID-19 vaccination acceptance. We aimed to examine the psychological mechanisms that could explain such vaccination disparities. This study used data from serial population-based surveys conducted since the COVID-19 vaccination programme being launched in Hong Kong (N = 28,734). We first assessed the correlations of community-level and individual-level social vulnerability with COVID-19 vaccination acceptance. Structural equation modelling (SEM) was then conducted to test whether psychological distress measured by PHQ-4 can account for the associations between participants' socio-economic vulnerability and COVID-19 vaccination acceptance. The third part analysis examined whether perceived negativity of vaccine-related news and affect towards COVID-19 vaccines accounted for the association between psychological distress and COVID-19 vaccination. Communities with higher social vulnerability scores and participants who had more vulnerable socio-economic status showed lower COVID-19 vaccination acceptance. Individuals with more vulnerable socio-economic status reported higher psychological distress, which lowered COVID-19 vaccination acceptance. Furthermore, higher psychological distress was associated with lower vaccination acceptance through its psychological mechanisms of processing vaccine-related information. We proposed a renewed focus on tackling psychological distress rather than merely increasing vaccine accessibility in more socio-economic-disadvantaged groups for promoting COVID-19 vaccination acceptance.

Factors associated with COVID-19 vaccine uptake among foreign migrants in China

Background/Purpose

The COVID-19 outbreak created unique policy challenges for vaccinating special groups like migrants. As part of sustainable development goals, the equitable distribution of the COVID-19 vaccine can contribute to ensuring health for all. This study examined COVID-19 vaccine uptake among foreign migrants in China based on sociodemographics, cultural beliefs, past vaccine behaviors, and psychosocial factors.

Design

An online cross-sectional survey was conducted among foreign migrants in mainland China via social media platforms from 21 November through 20 December 2021. Bivariate (unadjusted odd-ratio) and multivariate logistic regression analyses were performed to establish the correlates of COVID-19 vaccine uptake.

Result

Surveyed foreign migrants that are culture neutral (AOR: 2.5, CI: 95%, 1.02-5.90, p = 0.044), willing to pay for vaccination (AOR: 2.27, CI: 95%, 1.18-3.98, p = 0.012), believe in vaccine efficacy (AOR: 3.00, CI: 95%, 1.75-5.16, p < 0.000), have poor psychological health (AOR: 1.96, CI: 95%, 1.14-3.38, p = 0 0.014), and have higher perceived seriousness of COVID-19 (AOR: 2.12, CI: 95%, 1.26-3.57, p = 0.005) are more likely to receive COVID-19 vaccine. Those migrants with a history of declining vaccination (AOR: 0.34, CI: 95%, 0.18-0.65, p = 0.000) and middle-income earners $1701-3500 (AOR: 0.43, CI: 95%, 0.23-0.82, p = 0.010) are less likely to receive the COVID-19 vaccine.

Conclusion

This study brings a unique perspective to understanding vaccine behavior among international migrants in China. There is an urgent call from the World Health Organization and countries for complete vaccination and efforts to improve vaccine coverage. However, fewer studies have been conducted globally on the vaccination of migrant populations. The current study provides empirical information to increase the knowledge of the correlates of vaccine behavior among immigrants in countries around the globe. Future studies should conduct cross-country comparisons to understand the factors associated with increasing vaccination rates among immigrant populations to formulate a strong policy to increase vaccine coverage among immigrant populations across countries.

From Conspiracy to Hesitancy: The Longitudinal Impact of COVID-19 Vaccine Conspiracy Theories on Perceived Vaccine Effectiveness

The embrace of coronavirus disease 2019 (COVID-19) vaccine conspiracies has been linked to vaccine hesitancy. This study aimed to investigate the relationship between COVID-19 vaccine conspiracy theories and perceived vaccine effectiveness. The study utilized a longitudinal follow-up study in which adults in Chile completed surveys in December 2020 (T1) and May 2021 (T2). The psychometric properties of the five-item instrument on conspiracy theories for the COVID-19 vaccine were evaluated using data from T1 (n = 578). A confirmatory one-factor structure with suitable indicators of reliability was found. The longitudinal analysis (n = 292) revealed that conspiracy theories about the COVID-19 vaccine in T1 were associated with lower beliefs in its effectiveness in T2. However, no significant association was found between beliefs in effectiveness in T1 and conspiracy theories in T2. The study suggests that beliefs in conspiracy theories may temporally precede beliefs in vaccine effectiveness for COVID-19. The results have implications for strategies to address vaccine conspiracy beliefs and their implementation at the public policy level.

A Discrete Choice Analysis Comparing COVID-19 Vaccination Decisions for Children and Adults

IMPORTANCE

COVID-19 vaccination rates in the US remain below optimal levels. Patient preferences for different attributes of vaccine products and the vaccination experience can be important in determining vaccine uptake decisions.

OBJECTIVE

To assess preferences for attributes of adult and pediatric COVID-19 vaccination among US adults.

DESIGN, SETTING, AND PARTICIPANTS

An online survey of a national panel of 1040 US adults was conducted in May and June 2021. A discrete choice analysis was used to measure the relative value of each attribute in the decision to choose a COVID-19 vaccination option for adults or children. Six attributes were used to described hypothetical vaccination options: vaccine effectiveness, mild side effects, rare adverse events, number of doses, time required for vaccination, and regulatory approval. Respondents chose between hypothetical vaccination profiles or no vaccination. Additional survey questions asked about vaccination beliefs, COVID-19 illness experience, COVID-19 risk factors, vaccination status, and opinions about the risk of COVID-19.

EXPOSURES

Respondents chose which vaccine profile they would prefer to receive for themselves (or no vaccination). Respondents then considered an identical set of profiles for a hypothetical child aged 0 to 17 years.

MAIN OUTCOMES AND MEASURES

Relative value of vaccination-related attributes were estimated using Bayesian logit regression. Preference profiles for subgroups were estimated using latent class analyses.

RESULTS

A total of 1040 adults (610 [59%] female; 379 participants [36%] with an age of 55 years and older years) responded to the survey. When asked about vaccination choices for themselves, participants indicated that vaccine effectiveness (95% vs 60%) was a significant attribute (β, 9.59 [95% CrI, 9.20-10.00] vs β, 0.41 [95% CrI, 0-0.80]). Respondents also preferred fewer rare adverse events (β, 6.35 [95% CrI, 5.74-6.86), fewer mild side effects (β, 5.49; 95% CrI, 5.12-5.87), 1 dose (β, 5.41; 95% CrI, 5.04-5.78), FDA approval (β, 6.01; 95% CrI, 5.64-6.41), and shorter waiting times (β, 5.67; 95% CrI, 4.87-6.48). Results were very similar when framing the question as adult or child vaccination, with slightly stronger preference for fewer rare adverse events for children. Latent class analysis revealed 4 groups of respondents: (1) individuals sensitive to safety and regulatory status, (2) individuals sensitive to convenience, (3) individuals who carefully considered all attributes in making their choices, and (4) individuals who rejected the vaccine.

CONCLUSIONS AND RELEVANCE

In this survey study of US adults, the identification of 4 distinct preference groups provides new information to guide communications to support vaccine decision making. In particular, the group that prioritize convenience (less time required for vaccination and fewer doses) may present an opportunity to create actionable strategies to increase vaccination uptake for both adult and pediatric populations.

The Role of Trust in COVID-19 Vaccine Acceptance: Considerations from a Systematic Review

The goal of this research was to provide an overview of the role of trust in determining COVID-19 vaccine acceptance. Trust proved to be a key issue in all the strategic phases of the pandemic, a decisive element for the success of the worldwide vaccination campaign. By introducing a comprehensive systematic review of the state-of-the-art (N = 43), we intend to shed light on the various forms of trust that have been considered and how these relate to citizens’ vaccine acceptance. The analysis shows that trust has been used extensively, with particular reference to the COVID-19 vaccine, governments, manufacturers, healthcare systems, and science. A more in-depth analysis has also allowed us to evaluate the role that these factors have had and the social phenomena in which they have been decisive. Most notably, we proved that, in the different contributions, trust in the COVID-19 vaccine has a strong correlation with vaccine acceptance (R = 0.78, p < 0.01). Overall, vaccine acceptance emerges as a complex phenomenon that needs to be understood through the strictly interlaced relations of trust in the various factors coming into play. Besides clarifying what happened in previous years, the considerations included in this work also represent an important and useful interpretative framework to help public institutions and the healthcare system in the future.

Understanding Factors Influencing Polio Vaccine Uptake in Ghana-Developing Meaningful Community Mobilization and Engagement Strategies in Collaboration with Religious Leaders

This qualitative study explores how religious leaders in Ghana view polio and polio vaccine-related knowledge and perceptions of the community members. It also examines the personal characteristics of those who are most likely to accept or reject the vaccine. On the basis of the findings, this study provides a set of evidence-based recommendations to support religious leaders' efforts to create polio vaccine demand in their communities. The study is based on focus group discussions conducted with religious leaders from various geographic locations across Ghana. The discussions were transcribed verbatim and analyzed thematically. Twenty religious leaders, including Christian, Muslim, and leaders of traditional African religions, participated in the study. The findings show that both religious leaders and community members lack knowledge and have multiple culturally and religiously influenced explanations for polio. In addition, the findings reveal that vaccine safety and efficacy are linked to emotional narratives, and receiving the polio vaccine is not a social norm in all communities. Educated mothers in urban settings were identified as those most receptive to the polio vaccine. To create polio vaccine demand, religious leaders need to combat misinformation and the negative perceptions about the vaccine. Recommendations include conveying high-quality information to community members, developing tactics to address culturally and religiously sensitive matters, using emotionally inspired personal accounts to enhance positive attitudes toward polio vaccines and act as catalysts for positive social norms towards the polio vaccine. Educated mothers from urban areas can be engaged as champions in vaccine demand creation.

Willingness-to-pay for a booster dose of inactivated SARS-CoV-2 vaccine in Taizhou, China

This study was conducted to ascertain whether people in China would be willing to pay for an inactivated COVID-19 vaccine booster dose. An online survey estimating participants' willingness to pay (WTP) for a booster dose of COVID-19 vaccine was conducted in Taizhou, China. The participants received ane-mail or e-poster on WeChat. A total of 1576 subjects participated the survey. A total of 66.4% (1046/1576) of the respondents were willing to pay for a booster dose of COVID-19 vaccine for themselves. Using binary logistic regression analysis, the following factors were significantly related to a WTP for a booster dose of COVID-19 vaccine: 1) confidence in the safety of the COVID-19 vaccines (high vs. low, OR: 4.30, 95%CI: 1.61-11.43), 2) confidence in the preventive effectiveness of the COVID-19 vaccines against SARS-CoV-2 virus (moderate vs. little, OR: 1.76, 95%CI: 1.30-2.38; great vs. little, OR: 2.244, 95%CI: 1.62-3.12), and 3) COVID-19 vaccine hesitancy (unhesitant vs. very unhesitant, OR: 0.67, 95%CI: 0.45-1.02; hesitant vs. very unhesitant, OR: 0.29, 95%CI: 0.19-0.44; very hesitant vs. very unhesitant, OR: 0.09, 95%CI: 0.03-0.27). This study revealed that a moderate proportion of participants responded that they would be willing to pay for a booster dose of COVID-19 vaccine. These findings suggest the importance of a detailed assessment and a health education plan that better understands the population's risk perception as well as the potential health risks in China.

Acceptance and willingness to purchase a hypothetical COVID-19 vaccine in a region under Shariah law: A cross-sectional study in Aceh, Indonesia

Vaccines are urgently needed to control the coronavirus disease 2019 (COVID-19) pandemic. The aim of this study was to determine the acceptance of and willingness to purchase a hypothetical COVID-19 vaccine in the general population of Aceh, a holistic Shariah law implementation province in Indonesia. An online cross-sectional study was conducted using a quota sampling technique between 1 to 24 September 2021. To determine hypothetical vaccine acceptance, respondents were asked if they were willing to accept vaccines with combinations of either 50% or 95% effectiveness and either 5% or 20% risk of adverse effects. Willingness to purchase was assessed by asking whether the participants would pay for such vaccines at certain price points. Logistic regression analysis was used to assess the associated determinants. Out of 377 respondents included in the final analysis, 86.5% were willing to accept a COVID-19 vaccine with 95% effectiveness and 5% adverse effects. The acceptance rate dropped to 45.1% if the risk of adverse effects was 20%. Vaccines with 50% effectiveness and 5% adverse effects were acceptable to 42.2% but the acceptance went down to 17.2% if the risk of adverse effects increased to 20%. Multivariate analysis found that men were twice as likely to accept a vaccine with 95% effectiveness and 5% adverse effects compared to females (aOR: 2.01; 95% CI 1.05-3.86). We found that 156/377 (41.3%) of respondents were willing to purchase a COVID-19 vaccine and of these participants 71.1% were willing to pay between Indonesian Rupiah (IDR) 50,000-150,000 (US$ 3.33-10.00). In conclusion, the acceptance rate of a hypothetical COVID-19 vaccine varied based on effectiveness and the risk of adverse effects.

Immunogenicity and Reactogenicity of the Booster Dose of COVID-19 Vaccines and Related Factors: A Panel Study from the General Population in Serbia

The Republic of Serbia applied the booster dose of the following COVID-19 vaccines: BNT162b2 mRNA (Pfizer-BioNTech), Sinopharm BBIBP-CorV (Vero Cell®), Gam-COVID-Vac (Sputnik V) and ChAdOk1 nCoV-19 (AstraZeneca). We aimed to examine the immunogenicity and reactogenicity of the booster dose and identify factors related to immune response and adverse events. Panel study, conducted during August and September 2021, included 300 persons receiving the booster dose at the Institute of Public Health of Serbia. Blood samples were taken on the day of receiving the booster dose, and after 7 and 28 days. When applying homologous regimen, the average increase in anti-spike immunoglobulin G was 8782.2 (after 7 days), 1213.9 after 28 days, while 9179.5 (after 7 days) and 16,728.1 after 28 days of heterologous regimen. Sinopharm BBIBP-CorV (p < 0.001) and Sputnik V (p < 0.001), age 65 and over (p = 0.001) and currently smoking (p < 0.001) were independently associated with lower levels of anti-spike immunoglobulin G. Female sex (OR = 1.77; 95%CI = 1.01−3.12), previous COVID-19 infection (OR = 3.62; 95%CI = 1.13−11.63) and adverse events after the second dose (OR = 2.66; 95%CI = 1.33−5.32) were independently associated with intense systemic adverse events 7 days after. Booster dose significantly increased antibodies titers, especially 28 days after heterologous regimen, without a significant increase in reactogenicity.

Percentages of Vaccination Coverage Required to Establish Herd Immunity against SARS-CoV-2

The pandemic associated with SARS-CoV-2 is a worldwide public health challenge. The WHO has proposed to achieve 70% COVID-19 vaccination coverage in all countries by mid-2022. Nevertheless, the prevention strategy based on COVID-19 vaccination and other applied prevention measures has not been sufficient to prevent SARS-CoV-2 epidemic waves. This study assessed the vaccination coverage that would be required to establish herd immunity against SARS-CoV-2, taking into account virus transmissibility (R_o values from 1.1 to 10) and COVID-19 vaccination effectiveness. The study found that high percentages of vaccination coverage and high levels of vaccination effectiveness are necessary to block the transmission of Omicron and other SARS-CoV-2 variants with greater infectious capacity. COVID-19 vaccination programs could establish herd immunity against SARS-CoV-2, with R_o values ranging from 3 to 10 and levels of COVID-19 vaccination effectiveness of 70–100%. Factors reducing COVID-19 vaccination effectiveness (emergent variants, infections among vaccinated individuals, high risk individuals) and factors increasing SARS-CoV-2 transmissibility (close settings) increased the percentages of vaccination coverage that would be required to establish herd immunity. Two measures should be implemented to establish herd immunity against SARS-CoV-2: (1) achieve ≥ 90% COVID-19 vaccination coverage in all countries worldwide, and (2) increase the effectiveness of COVID-19 vaccines in preventing Omicron infection to at least 88%.

Chinese University Students' Awareness and Acceptance of the COVID-19 Vaccine: A Cross-Sectional Study

Purpose

The emergence of the mutant virus has exacerbated the COVID-19 epidemic, and vaccines remain an effective and viable means of resistance. As a socially influential young group, university students’ awareness and acceptance of the COVID-19 vaccine are crucial to achieving herd immunity. This study aimed to assess the awareness and acceptance of the COVID-19 vaccine among Chinese university students and identify possible factors associated with their awareness level and vaccine hesitancy.

Patients and Methods

An anonymous cross-sectional survey was conducted among Chinese university students between 10 and 28 June 2021. We collected information on the demographic characteristics, awareness and acceptance of the COVID-19 vaccine, and influencing factors. Sleep disturbances and anxiety disorders were also evaluated. Multinomial logistic regression analyses were performed.

Results

Among the 721 participants (aged 18 to 23 years) with a female predominance (68.9%), 40.4% of cases exhibited moderate awareness the COVID-19 vaccine, and 87.4% of cases expressed high acceptance of the vaccine. Participants’ awareness of the COVID-19 vaccine was associated with gender, ethnicity, region of residence, grade level, satisfaction with current state of pandemic control, the perceived likelihood of a COVID-19 pandemic rebound, the source number of COVID-19 information, concerns about differences in vaccine manufacturers, acceptance of current state-approved vaccines and insomnia level. Furthermore, age, preferred channels for vaccination and the acceptance of current state-approved vaccines were significantly associated with their acceptance of the vaccine.

Conclusion

This study reflected Chinese university students’ high acceptance, but insufficient awareness of the COVID-19 vaccine, some students have insomnia and anxiety problems. These require the government to take measures such as individualized publicity and education, adding professional psychological counseling courses to improve the university students’ awareness of vaccines and public health events, and comprehensively promote vaccination to cope with the ever-changing situation of the COVID-19 epidemic.

Individual Preferences for COVID-19 Vaccination under the China’s 2021 National Vaccination Policy: A Discrete Choice Experiment Study

(1) Background: Since China’s national vaccination policy announcement in January 2021, individual vaccination preferences related to vaccine characteristics, social relationships, sociodemographic characteristics and cognition remain opaque. This study aims to investigate vaccination preferences regarding these attributes, and to assess changes in individual vaccine preferences since the pre-2021 emergency vaccination phase. (2) Methods: The two-part questionnaire surveyed 849 individuals between May and June 2021 in Qingdao, China. The survey contained eight binary choice tasks that investigated preference trade-offs. Respondents’ sociodemographic characteristics, including age, sex, urban/rural residence, income, education and whether living with the young or old, were also collected. Conditional logit, mixed logit and latent class models were used to quantify preference utility and identify preference heterogeneity. (3) Results: Vaccine effectiveness, vaccine side effects, duration of protection and probability of infection all significantly affected vaccination utility. Preference heterogeneity based on individual social relationships and sociodemographic characteristics were also established. Marginal analysis showed that compared to the pre-2021 phase, individuals’ preferences had shifted towards vaccines with longer protection periods and better accessibility. (4) Conclusion: This study will inform the full rollout of China’s 2021 national vaccination program and provide valuable information for future vaccination policy design to meet resurgent COVID-19 risks.

Study on the Refusal of Vaccination against COVID-19 in Romania

The refusal to be inoculated with the anti-COVID-19 vaccine by a part of the Romanian population becomes a barrier against controlling and stopping this particularly infectious virus. The rapid evolution of COVID-19 vaccines has created confusion regarding health and safety. Many Romanian citizens refuse vaccination because of fears generated by uncertainties based on information obtained from fake news. At the present moment, January 2022, Romania has one of the lowest vaccination rates in the European Union, below 45% of the total population. In our study, we want to identify the determining factors behind the refusal of vaccination, offering a sociological analysis that, we hope, will help to understand this phenomenon. The analysis revealed that 81% of the respondents trust the mandatory vaccines under the national scheme and 57.3% trust the optional ones other than the anti-COVID-19 vaccines (like Rotavirus, Hepatitis A and B, Influenza, Meningococcal, Pneumococcal, etc.) and have less confidence in the anti-COVID-19 vaccines. The study also reveals a very high percentage of respondents who trust fake news claims.

Using a health belief model to assess COVID-19 vaccine intention and hesitancy in Jakarta, Indonesia

Since January 2021, Indonesia has administered a nationwide COVID-19 vaccination. This study examined vaccine intention and identified reasons for vaccine hesitancy in the capital city of Jakarta. This is a cross-sectional online survey using the Health Belief Model (HBM) to assess vaccine intent predictors and describe reasons for hesitancy among Jakarta residents. Among 11,611 respondents, 92.99% (10.797) would like to get vaccinated. This study indicated that all HBM constructs predict vaccine intention (P< 0.05). Those with a high score of perceived susceptibility to the COVID-19 vaccine were significantly predicted vaccine hesitancy (OR = 0.18, 95% CI: 0.16-0.21). Perceived higher benefits of COVID-19 vaccine (OR = 2.91, 95% CI: 2.57-3.28), perceived severity of COVID-19 disease (OR: 1.41, 95% CI: 1.24-1.60), and perceived susceptibility of the current pandemic (OR = 1.21, 95% CI: 1.06-1.38) were significantly predicted vaccination intend. Needle fears, halal concerns, vaccine side effects, and the perception that vaccines could not protect against COVID-19 disease emerged as reasons why a small portion of the respondents (n = 814, 7.23%) are hesitant to get vaccinated. This study demonstrated a high COVID-19 vaccine intention and highlighted the reasons for vaccine refusal, including needle fears, susceptibility to vaccine efficacy, halal issues, and concern about vaccine side effects. The current findings on COVID-19 vaccination show that the government and policymakers should take all necessary steps to remove vaccine hesitancy by increasing awareness of vaccine efficacy and benefit interventions.

Mediators of Racial Differences in COVID-19 Vaccine Acceptance and Uptake: A Cohort Study in Detroit, MI

Despite their disparate rates of infection and mortality, many communities of color report high levels of vaccine hesitancy. This paper describes racial differences in COVID-19 vaccine uptake in Detroit, and assesses, using a mediation model, how individuals' personal experiences with COVID-19 and trust in authorities mediate racial disparities in vaccination acceptance. The Detroit Metro Area Communities Study (DMACS) is a panel survey of a representative sample of Detroit residents. There were 1012 respondents in the October 2020 wave, of which 856 (83%) were followed up in June 2021. We model the impact of race and ethnicity on vaccination uptake using multivariable logistic regression, and report mediation through direct experiences with COVID as well as trust in government and in healthcare providers. Within Detroit, only 58% of Non-Hispanic (NH) Black residents were vaccinated, compared to 82% of Non-Hispanic white Detroiters, 50% of Hispanic Detroiters, and 52% of other racial/ethnic groups. Trust in healthcare providers and experiences with friends and family dying from COVID-19 varied significantly by race/ethnicity. The mediation analysis reveals that 23% of the differences in vaccine uptake by race could be eliminated if NH Black Detroiters were to have levels of trust in healthcare providers similar to those among NH white Detroiters. Our analyses suggest that efforts to improve relationships among healthcare providers and NH Black communities in Detroit are critical to overcoming local COVID-19 vaccine hesitancy. Increased study of and intervention in these communities is critical to building trust and managing widespread health crises.