First COVID-19 Booster Dose in the General Population: A Systematic Review and Meta-Analysis of Willingness and Its Predictors

Change in intention and hesitancy regarding COVID-19 vaccines in a cohort of adults in Quebec during the pandemic

Although COVID-19 vaccine uptake was high in Quebec for the primary series, vaccine acceptance decreased for the subsequent booster doses. This article presents the evolution of vaccine intention, self-reported vaccination behaviors, and vaccine hesitancy over 2 years. A series of cross-sectional surveys were conducted in Quebec between March 2020 and March 2023, with a representative sample of 3,330 adults recruited biweekly via a Web panel. Panelists could have answered multiple times over the course of the project. A cohort of respondents was created to assess how attitudes and behaviors about COVID-19 vaccines evolved. Descriptive statistics and multivariate logistic regressions were performed. Among the 1,914 individuals with no or low intention of getting vaccinated in Fall 2021 (Period 1), 1,476 (77%) reported having received at least two doses in the Winter 2023 (Period 2). Not believing in conspiracy theory (OR = 2.08, 95% CI: 1.65-2.64), being worried about catching COVID-19 (OR = 2.12, 95% CI: 1.65-2.73) and not living in a rural area (ORs of other areas are 2.27, 95% CI: 1.58-3.28; 1.66, 95% CI: 1.23-2.26; 1.82 95% CI: 1.23-2.73) were the three main factors associated with being vaccinated at Period 2. Among the 11,117 individuals not hesitant at Period 1, 1,335 (12%) became hesitant at Period 2. The three main factors significantly associated with becoming vaccine hesitant were the adherence to conspiracy theories (OR = 2.28, 95% CI: 1.95-2.66), being a female (OR = 1.67, 95% CI: 1.48-1.90) and being younger than 65 years old (the ORs for 18-34, 35-49, and 50-64 compared with 65 and over are 2.82, 95% CI: 2.32-3.44; 2.39, 95% CI: 2.00-2.86 and 1.82, 95% CI: 1.55-2.15 respectively). As the pandemic is over, monitoring the evolution of vaccine attitudes and uptake will be important.

Impact of the COVID-19 vaccination on confusion around vaccination in general: A longitudinal study on a university population over 18 months

Even before the COVID-19 pandemic, vaccine hesitancy was one of the main global public health threats. Unfortunately, the COVID-19 crisis and its associated risks only reinforced this hesitancy. This study aimed to identify to what extent the COVID-19 vaccination affected confusion around vaccination in general, its change and any associated factors. A questionnaire was distributed to the university population of Liège between April-June 2021 (Time 1) and July-September 2022 (Time 2). The impact of the COVID-19 vaccination on confusion around vaccination in general (score 0 to 100) was divided into three groups based on the tertiles of the study sample at different times and whether or not any change had been observed. Ordinal and multinomial regression analyses were performed to assess the relationship between the confusion and various determinants. The sample consisted of 491 participants. Time 1 vs Time 2, 41.3% vs 35.4% seemed to be less confused, 24.2% vs 28.7% were moderately confused and 34.4% vs 35.8% more confused, respectively. In terms of change, 19.4% of participants were less confused, 55.2% had not changed their opinion and 25.5% were more confused. The determinants causing confusion at both times and regarding change were self-perception, health literacy, past vaccination experiences and COVID-19 related factors (COVID-19 vaccination intention and trust in source of information at Time 1; preferred source of information, trust in vaccine producers and conspiratorial beliefs at Time 2; trust in vaccine producers for change). The results demonstrated that the COVID-19 vaccination impacted confusion around vaccination in general. Both unrelated and related COVID-19 factors, particularly regarding the progression of the pandemic, seem to have contributed to this confusion. Contributing factors require a personalised approach, evidence-based information being communicated with messages adapted to the situation and its evolution designed to allay individuals' fears about vaccination.

Using cluster analysis to explore COVID-19 vaccine booster hesitancy by levels of medical mistrust in fully vaccinated US adults

BACKGROUND

Underlying causes of vaccine hesitancy could significantly affect successful uptake of the SARS-CoV2 vaccine booster doses during new waves of COVID-19. Booster rates among US adults are far below what is needed for immunity, but little is known about booster hesitancy among fully vaccinated adults and whether medical mistrust exacerbates barriers to uptake.

METHODS

A cross-sectional survey was completed among 119 adults in Philadelphia, PA who reported having received the primary SARS-CoV2 vaccine series but not a booster dose. Using the LaVeist Medical Mistrust (MM) Index, a k-means cluster analysis showed two clusters (Low MM, High MM) and differences in attitudes and perceptions about COVID-19 booster vaccines were assessed using F-tests.

RESULTS

Respondents were 62% Black and female; mean age was 41; 46% reported earning less than $25,000 and 53% had a high school education or less. Overall intention to get boosted was low (mean 3.3 on 0-10 scale). Differences in COVID-19 booster perceptions between those with High (n = 56) vs. Low (n = 59) MM were found, independent of any demographic differences. Most statements (7/10) related to reasons to not be boosted were significant, with those with High MM indicating more concern about feeling sick from the vaccine (F=-3.91, p≤ .001), beliefs that boosters are ineffective for vaccinated people (F= -3.46, p≤ .001), and long-term side effect worries (F=-4.34, p≤ .001). Those with High MM were also more concerned about the adverse effects of the vaccine (F=-2.48, p=.02), but were more likely to trust getting information from doctors or healthcare providers (F= -2.25, p=.03).

CONCLUSIONS

Results indicate that medical mistrust is an important independent construct when understanding current COVID-19 booster hesitancy. While much work has looked at demographic differences to explain vaccine hesitancy, these results suggest that further research into understanding and addressing medical mistrust could be important for implementing interventions to increase booster rates.

Evidence brief on facilitators, barriers and hesitancy of COVID-19 booster doses in Canada

Background

Understanding the facilitators, barriers and hesitancy to accepting COVID-19 booster doses is important for encouraging recommended vaccination. This evidence brief summarizes literature on the intention to accept or reject COVID-19 vaccine booster doses and the factors associated with intention/uptake among individuals in Canada.

Methods

A database of COVID-19 literature established at the Public Health Agency of Canada was searched for articles referencing vaccination and knowledge, attitudes and behaviours towards COVID-19 boosters. A grey literature search of Canadian governmental and academic institutions was also conducted. Primary research conducted in Canada (n=21) and relevant systematic reviews of the global literature (n=8) were included in this evidence brief.

Results

Intentions to get a booster dose in the general population have decreased between 2021-2023, with intentions varying across subpopulations. In Canada and within the global systematic reviews, facilitators, barriers and hesitancy were similar. Older age was the most common factor positively associated with intention/uptake of a booster, and the most common motivators were government/healthcare provider recommendations and helping to protect others. The main reasons for hesitancy were concerns about vaccine side effects and a lack of belief in the vaccine's efficacy.

Conclusion

Intentions to get a booster dose have decreased in Canada. Understanding the reasons for vaccine hesitancy and motivators for obtaining a booster can help guide future public health COVID-19 booster vaccination programs.

Messaging to Reduce Booster Hesitancy among the Fully Vaccinated

Vaccine hesitancy was a serious problem in the United States throughout the COVID-19 pandemic, due in part to the reduction in public trust in science that accompanied the pandemic. Now we are facing a new, similar but more extensive problem: booster hesitancy. Even fewer Americans are current on the mRNA booster. We present the results of an experiment with residents of the US who received all initial doses of the mRNA vaccine but who were not up to date on the booster. Participants read a scientific explanation describing either the safety or the effectiveness of the boosters or nothing in the control group. The explanations significantly increased (compared to the control) participants' perceptions of the safety and effectiveness of the mRNA booster, as well as their willingness to get boosted. Explanations also improved emotions and attitudes toward the booster. Furthermore, although liberals were significantly more willing to get boosted than were conservatives, improvement due to the explanations was similar across political ideology groups. However, when interactions were observed, conservatives increased to a greater degree. Importantly, the explanations increased participants' perception of scientists' expertise and knowledge, as well as participants' trust in scientists and the vaccine technology.

Factors related to first COVID-19 booster vaccine acceptance in Indonesia: A cross-sectional multi-center study

A positive community perception of the coronavirus disease 2019 (COVID-19) vaccination program is crucial for increasing vaccination coverage and achieving herd immunity. This study aimed to identify factors influencing the acceptance of a COVID-19 booster vaccine in Indonesia. It was conducted as a cross-sectional, multicenter study using a validated questionnaire distributed online to Indonesian participants aged 18 years and older. The questionnaire covered sociodemographic characteristics, clinical conditions of both the participants and their closest contacts, the Health Belief Model (HBM) domain, and preferences for the location of receiving a booster vaccine, as well as reasons for declining a booster vaccine. Of 1550 respondents, 78.6% had received the first COVID-19 booster dose. Sociodemographic factors influencing first booster vaccine acceptance in Indonesia included age (OR36-45 vs 18-25 years: 2.43; 95%CI: 1.13-5.24; OR>45 vs 18-25 years: 3.58, 95%CI: 1.96-6.52), length of education (OR13-16 vs <12 years: 1.34; 95%CI: 1.00-1.80; OR>16 vs <12 years: 4.15, 95%CI: 2.12-8.09), monthly income (ORIDR3,500,000 vs 1,500,000: 1.72; 95%CI: 1.19- 2.49), and occupation (ORHealth workers vs not-working: 1.81; 95%CI: 1.00-3.29). Clinical aspects and HBM domains associated with booster vaccine acceptance were the presence of chronic disease (OR: 1.94; 95%CI: 1.03-3.66), previously tested positive for COVID-19 (OR: 1.90; 95%CI: 1.24-2.89), having a family member or friend who was hospitalized due to COVID-19 (OR: 1.86; 95%CI: 1.32-2.62), perceived susceptibility (OR: 1.20; 95%CI: 1.02-1.41), perceived access barriers to COVID-19 vaccination (OR: 0.52; 95%CI: 0.44-0.61), and perceived benefits of COVID-19 vaccination (OR: 1.67; 95%CI: 1.41-1.97). In conclusion, factors influencing the first COVID-19 booster vaccine acceptance in Indonesia ranged from demographic and clinical characteristics as well as HBM domains. Effective strategies to expand COVID-19 booster vaccine coverage should consider these factors to encourage participation in the vaccination program.

Willingness to get vaccinated initially and yearly against COVID-19 and its association with vaccine hesitancy, vaccine knowledge and psychological well-being: a cross-sectional study in UK adults

OBJECTIVES

This study explores the association between vaccine hesitancy, vaccine knowledge and psychological well-being with (1) receipt of/willingness to receive an initial vaccine against COVID-19, and (2) willingness to get vaccinated yearly against COVID-19. The importance of different vaccine attributes (eg, vaccine technology, effectiveness, side effects) to choose a specific COVID-19 vaccine was also assessed.

DESIGN

Cross-sectional survey administered during May to June 2021 on vaccine hesitancy, vaccine knowledge, psychological well-being, willingness to receive COVID-19 vaccines, sociodemographics and COVID-19-related factors.

SETTING

UK.

PARTICIPANTS

A self-selected sample of 1408 adults.

OUTCOME MEASURES

Receipt of/willingness to receive COVID-19 vaccine for the first time and yearly.

RESULTS

Receipt of/willingness to receive a vaccine against COVID-19 initially and yearly were high (97.0% and 86.6%, respectively). Vaccine hesitancy was negatively associated with receipt of/willingness to receive vaccine initially/yearly (adjusted OR (aOR)=0.09, 95% CI 0.04 to 0.26, p<0.001/aOR=0.05, 95% CI 0.03 to 0.09, p<0.001). Vaccine knowledge and psychological well-being were positively associated with willingness to receive a yearly vaccine (aOR=1.81, 95% CI 1.43 to 2.29, p<0.001 and aOR=1.25, 95% CI 1.02 to 1.51, p=0.014, respectively), and general vaccine knowledge also with receipt of/willingness to receive vaccine initially (aOR=1.69, 95% CI 1.18 to 2.42, p=0.004). Vaccine effectiveness was the most important attribute for participants to choose a specific COVID-19 vaccine.

CONCLUSIONS

Improving vaccine knowledge and emphasising vaccine efficacy may minimise vaccine hesitancy and increase COVID-19 vaccine uptake.

Impact of prior SARS-CoV-2 infection on college students' hesitancy to receive additional COVID-19 vaccine booster doses: A study from Taizhou, China

Purpose

This study aimed to examine the impact of a history of SARS-CoV-2 infection on the hesitancy of college students to receive additional COVID-19 vaccine booster doses.

Methods

A population-based self-administered online survey was conducted in July 2024 in Taizhou, China. A total of 792 respondents were included in this study. Logistic regression was conducted to identify factors associated with college students' hesitation to receive booster doses of the COVID-19 vaccine.

Results

Of 792 respondents, 32.2 % hesitated to receive additional doses of the COVID-19 vaccine booster. Furthermore, 23.5 % of the respondents reported an increase in hesitancy to receiving additional COVID-19 vaccine booster doses compared to before they were infected with SARS-CoV-2. In the regression analyses, college students who had a secondary infection were more hesitant to receive additional COVID-19 vaccine booster doses (OR = 0.481, 95 % CI: (0.299-0.774), P = 0.003). Moreover, students with secondary infections who were male (OR = 0.417, 95 % CI: 0.221-0.784, P = 0.007), with lower than a bachelor's degree (OR = 0.471, 95 % CI: 0.272-0.815, P = 0.007), in non-medical majors (OR = 0.460, 95 % CI: 0.248-0.856, P = 0.014), and sophomores or below (OR = 0.483, 95 % CI: 0.286-0.817, P = 0.007) were more hesitant to receive additional COVID-19 vaccine booster doses.

Conclusion

A history of SARS-CoV-2 infection affects college students' hesitation to receive additional COVID-19 vaccine booster doses, which was higher in those who experienced secondary infections.

The Prevalence and Determinants of Hesitancy for Regular COVID-19 Vaccination among Primary Healthcare Patients with Asthma or COPD in Greece: A Cross-Sectional Study

The emergence of novel coronavirus mutations and signs of the waning immunity provided by COVID-19 vaccines underscore the importance of regular vaccination. This study aimed to investigate the prevalence of regular COVID-19 vaccination hesitancy and the factors that influence it among patients with asthma or chronic obstructive pulmonary disease (COPD) who visited primary care centers. The cross-sectional study was conducted in six primary healthcare centers in Crete, Greece (October-December 2023). Participants completed a questionnaire, which included questions about socio-demographic characteristics, health status, previous COVID-19 booster vaccination, attitudes, and beliefs about COVID-19 vaccination. Multivariate logistic regression was used to identify the factors that influenced vaccine hesitancy. Of the 264 participants, 65% exhibited hesitancy towards COVID-19 booster vaccination. Female gender, middle age, lower educational attainment, depression diagnosis, concerns about vaccine side effects, lack of confidence in vaccine efficacy, and reliance on media information were positively associated to vaccine hesitancy. Conversely, those having a cardiovascular disease or type 2 diabetes, those generally adhering to the recommendations of the treating physician, and those having previously received the flu vaccine or more than three COVID-19 vaccine doses were positively associated with regular COVID-19 vaccinations. Consequently, our findings could help develop strategies that could potentially reduce regular vaccination hesitancy among patients with asthma or COPD.

Pandemic antecedents - Exploring predictivity and relationships between COVID-19 vaccine uptake and influenza, shingles, and HPV vaccination

BACKGROUND

A wealth of extant research focuses on identifying barriers to, and predictors of, COVID-19 vaccination. In addition to treating COVID-19 vaccination and related experiences as antecedents, this study analyzes the relationships between COVID-19 vaccination experiences and intent to receive the flu, shingles, and HPV vaccines.

METHOD

Analyses were performed on the responses from U.S. survey panel of 1,024 participants (n = 1,024), 530 (51.8 %) who received at least a dose of the COVID-19 vaccine and 494 (48.2 %) who had not. Descriptive and inferential statistics identify participant demographic characteristics, prior vaccination behavior, vaccination intentions, risk behavior assessment, vaccination attitudes and beliefs, and the predictivity of COVID-19 vaccination, when treated as an antecedent.

RESULTS

Receiving a first dose of the COVID-19 vaccine interacted with receiving a past influenza vaccine, predicting the future intention to receive a COVID-19 vaccine or booster. Vaccine hesitancy in parents is significantly related to vaccination behaviors for themselves and their children. Analyses also showed differences between the vaccinated group (VG) and the unvaccinated group (UVG) on hesitancy, beliefs, and attitudes toward the COVID-19 vaccine.

CONCLUSION

Experience with COVID-19 vaccination and the relationship of those experiences with other vaccinations provide useful insight on leveraging vaccine uptake. Healthcare professionals should improve the COVID-19 vaccination experience and use vaccination appointments to promote other vaccinations. Research should continue to compare vaccination experiences and how they may persuade or dissuade vaccination intent for other vaccinations.

An intranasal combination vaccine induces systemic and mucosal immunity against COVID-19 and influenza

Despite prolonged surveillance and interventions, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses continue to pose a severe global health burden. Thus, we developed a chimpanzee adenovirus-based combination vaccine, AdC68-HATRBD, with dual specificity against SARS-CoV-2 and influenza virus. When used as a standalone vaccine, intranasal immunization with AdC68-HATRBD induced comprehensive and potent immune responses consisting of immunoglobin (Ig) G, mucosal IgA, neutralizing antibodies, and memory T cells, which protected the mice from BA.5.2 and pandemic H1N1 infections. When used as a heterologous booster, AdC68-HATRBD markedly improved the protective immune response of the licensed SARS-CoV-2 or influenza vaccine. Therefore, whether administered intranasally as a standalone or booster vaccine, this combination vaccine is a valuable strategy to enhance the overall vaccine efficacy by inducing robust systemic and mucosal immune responses, thereby conferring dual lines of immunological defenses for these two viruses.

Vaccine hesitancy for the COVID-19 vaccine booster dose among nursing home staff fully vaccinated with the primary vaccination course in Belgium

In Belgium, nursing home (NH) staff (NHS) and residents were prioritised for the initial COVID-19 vaccination and successive booster doses. The vaccination campaign for the first booster started in September 2021 in Belgian NH. Our first study about vaccine hesitancy towards the COVID-19 vaccine in Belgian NHS already showed a degree of fear for the primary vaccination course (T1). This new study aims to evaluate vaccine hesitancy to get the first booster (T2) in a population of fully vaccinated (with two doses) NHS. A random stratified sample of NHS who received the primary vaccination course (N = 954) completed an online questionnaire on COVID-19 booster hesitancy (between 25/11/2021 and 22/01/2022). NHS who hesitated or refused the booster were asked for the main reason for their hesitation/refusal. Overall, 21.0 % of our population hesitated before, were still hesitating or refused the booster, NHS that were not hesitant at T1 being 5.7 times less likely to hesitate to get the first booster dose (Adjusted OR 0.179, 95 % CI: 0.120, 0.267). Although there was a slight reduction (23.5 % to 20.1 %) in the proportion of NHS who hesitated/refused vaccination at T1 compared to T2 (p = 0.034), the fear of unknown effects was the principal reason for hesitation/refusal, already mentioned in our first study. NHS were not reassured concerning their initial fears. Given the likelihood that booster vaccinations will be necessary over the coming years, a communication strategy specific to NHS should be implemented.

Who is motivated to accept a booster and annual dose? A dimensional and person-centered approach

The transmissibility of new COVID-19 variants and decreasing efficacy of vaccines led authorities to recommend a booster and even an annual dose. However, people's willingness to accept new doses varied considerably. Using two independent longitudinal samples of 4596 (Mean age = 53.6) and 514 (Mean age = 55.9) vaccinated participants, we examined how people's (lack of) vaccination motivation for their first dose was associated with their intention to get a booster (Sample 1) and an annual dose (Sample 2) several months later (Aim 1). We also aimed to capture the impact of the motivational heterogeneity on these intentions by capitalizing on participants' different motivational profiles collected at baseline (Aim 2). Across both samples, autonomous motivation, controlled motivation, and distrust-based amotivation were uniquely related to, respectively, higher, lower, and even lower booster and annual dose intentions. Further, a two-step clustering procedure revealed five profiles, with the profiles characterized by higher autonomous motivation (i.e. Good Quality and High Quantity profiles) reporting the highest vaccination intentions and the profile characterized by the highest number of obstacles (i.e. Global Amotivated profile) yielding the lowest vaccination intentions. These results stress the critical need to support citizens' volitional endorsement of vaccination to harvest long-term benefits with respect to COVID-19.

Immunogenicity and Reactogenicity of Messenger RNA Coronavirus Disease 2019 Vaccine Booster Administered by Intradermal or Intramuscular Route in Thai Older Adults

BACKGROUND

Intradermal (ID) vaccination may alleviate COVID-19 vaccine shortages and vaccine hesitancy.

METHODS

Persons aged ≥65 years who were vaccinated with 2-dose ChAdOx1 12-24 weeks earlier were randomized to receive a booster vaccination by either ID (20 µg mRNA-1273 or 10 µg BNT162b2) or intramuscular (IM) (100 µg mRNA-1273 or 30 µg BNT162b2) route. Anti-receptor-binding domain (RBD) immunoglobulin G (IgG), neutralizing antibody (NAb), and interferon gamma (IFN-γ)-producing cells were measured at 2-4 weeks following vaccination.

RESULTS

Of 210 participants enrolled, 70.5% were female and median age was 77.5 (interquartile range, 71-84) years. Following booster dose, both ID vaccinations induced 37% lower levels of anti-RBD IgG compared with IM vaccination of the same vaccine. NAb titers against ancestral and Omicron BA.1 were highest following IM mRNA-1273 (geometric mean, 1718 and 617), followed by ID mRNA-1273 (1212 and 318), IM BNT162b2 (713 and 230), and ID BNT162b2 (587 and 148), respectively. Spike-specific IFN-γ responses were similar or higher in the ID groups compared with IM groups. ID route tended to have fewer systemic adverse events (AEs), although more local AEs were reported in the ID mRNA-1273 group.

CONCLUSIONS

Fractional ID vaccination induced lower humoral but comparable cellular immunity compared to IM and may be an alternative for older people.

CLINICAL TRIALS REGISTRATION

TCTR20220112002.

The Social Attitudes Towards the Booster Dose of the COVID-19 Vaccine and the Associated Factors Among Residents of Riyadh, Saudi Arabia

Background As a result of the Coronavirus (COVID-19) pandemic, global health was significantly affected. Therefore, the booster dose was approved to be administered to people who had completed a primary vaccination series in order to enhance their immunity. This study aims to identify the factors that lead to willingness or hesitancy toward the third/booster dose of the COVID-19 vaccine, to estimate the rate of acceptance and hesitancy toward the third/booster dose of the COVID-19 vaccine, and to measure third/booster dose COVID-19 vaccine literacy among residents of Riyadh. Methods This study is a quantitative analytical cross-sectional, questionnaire-based study from March 2022 to December 2022. The data were gathered using a convenience sampling technique from 435 participants in the Riyadh region 16 years old and above by using a validated questionnaire. Results Among the participants, 72.6% were females; 53.4% of young participants aged 16-25 years had a good knowledge of the booster dose versus 26.2% of those aged 45 years or above, with reported statistical significance (P=0.001). The functional literacy of the COVID-19 vaccine which is defined as the ability to read and write effectively was higher among the non-hesitant group compared to the hesitant group. The interactive/critical literacy of the COVID-19 vaccine, which is defined as the advanced abilities that enable people to make sense of information so they may take decisions that are relevant to their own lives, was higher among the non-hesitant group compared to the hesitant group. 72.2% of the study participants reported that if the booster dose of the COVID-19 vaccine was not mandatory by the government, they would not have taken it. Also, 19.1% thought that taking the booster dose of the COVID-19 vaccine would endanger their lives. Conclusion The findings of the current study revealed that the factors leading to the willingness or hesitancy toward the booster dose of the COVID-19 vaccine include age, gender, and side effects. Also, measuring the COVID-19 vaccine literacy revealed that it is higher among the non-hesitant group than the hesitant group although it was statistically insignificant. Meanwhile, further studies should be done to track and measure COVID-19 vaccine literacy over time, and examine the factors associated with the booster dose of COVID-19 vaccine hesitancy for more validation and application.

Factors associated with COVID-19 booster vaccine hesitancy: a nationwide, cross-sectional survey in Japan

OBJECTIVES

COVID-19 vaccine hesitancy/fatigue is increasing as the pandemic enters the endemic phase. The present study aimed to explore current perceptions about COVID-19 booster vaccination among the Japanese public.

STUDY DESIGN

This was a cross-sectional study.

METHODS

This cross-sectional study used data from the Japan COVID-19 and Society Internet Survey conducted in September 2021 and September 2022. The public's perceptions of COVID-19 vaccination and factors associated with COVID-19 booster vaccine hesitancy were analyzed.

RESULTS

In total, 56,735 respondents were included. In the Japan COVID-19 and Society Internet Survey 2021, 75.1% of the participants (21,126/28,118) had completed the primary vaccination series. In the 2022 survey, 74.1% of the respondents (21,216/28,617) completed the primary series of vaccination with booster doses. The proportion of fear toward COVID-19 and obtaining information about COVID-19 has decreased from 2021 to 2022. Factors independently associated with booster vaccine hesitancy were young age (range: 18-29 years; adjusted odds ratio [aOR]: 6.56), history of COVID-19 (aOR: 1.82), distrust of the Japanese government's COVID-19 prevention measures (aOR: 1.55), lack of confidence in COVID-19 vaccine efficacy (aOR: 1.30), lack of confidence in COVID-19 vaccine safety (aOR: 1.62), low reliance on the COVID-19 vaccine (aOR: 1.92), and belief in COVID-19 conspiracy theories (aOR: 1.77).

CONCLUSIONS

Providing clear and trustworthy information is critically important, especially targeted and tailored messages for the young generation, to promoting COVID-19 booster vaccination. Policymakers should therefore develop consistent and transparent communication strategies and the ability to respond promptly and flexibly to mitigate the negative impact of COVID-19 on the public while preparing for the next pandemic.

Changes in Confidence, Feelings, and Perceived Necessity Concerning COVID-19 Booster

The COVID-19 booster first became available to all adults in the U.S. in November 2021 and a bivalent version in September 2022, but a large population remains booster-hesitant; only 17% of Americans have obtained the updated vaccine as of June 2023. We conducted two cross-sectional surveys in 2021 and 2022 (n = 1889 and 1319) to determine whether changes in booster-related feelings or perceptions had occurred and whether they altered vaccination rates over time. We found that both positive and negative emotions had grown stronger between the two years, with the prevalence of annoyance increasing the most (21.5% to 39.7%). The impact of trust on booster intention more than doubled (OR = 7.46 to 16.04). Although perceived risk of infection decreased, more participants in 2022 indicated uncertainty or unwillingness to obtain a new booster than in 2021, while the proportion refusing a booster remained constant at 22.5%. Confidence in the COVID-19 vaccine and feelings of hope from the booster motivated acceptance; both were stronger predictors of booster receptivity than prior vaccination history. Our findings signal a need to rebuild trust by informing people of their continued risk and appealing to positive, especially optimistic emotions to encourage booster uptake. Future research should explore longitudinal trends in behavior and feelings toward new booster doses and the impact of prolonged vaccine hesitancy on infection rates.

The determinants of COVID-19 vaccination intention: a meta-review

Background

A large number of systematic reviews have been published that synthesized various determinants of COVID-19 vaccination intention (CVI). However, they reported inconsistent evidence. Therefore, we conducted a meta-review (systematic review of systematic reviews) to provide a comprehensive synthesis of factors influencing CVI.

Methods

This meta-review was conducted in accordance with PRISMA guidelines. PubMed, Scopus, Web of Science, and CINAHL were searched for systematic reviews published from 2020 to 2022 that examined the determinants of CVI. AMSTAR-2 critical appraisal tool was used to ensure the quality of included reviews, and ROBIS tool was used to evaluate the risk of bias.

Results

Globally, the average rate of COVID-19 vaccination intention was 56.97%. We identified 21 main determinants of CVI: socio-demographic, geographical location, social, political, government role, study timeline, attitude, perceived severity, perceived susceptibility, perceived benefits, perceived barriers, self-efficacy and perceived behavioral control, norms, trust, conspiracy theory/propaganda/misinformation, knowledge, information and communication, vaccination recommendation, vaccination history, history of COVID-19 infection, and health status and well-being.

Conclusions

These results suggest that COVID-19 vaccination intention is a complex process and is affected by numerous multidimensional factors. Therefore, integrated communication strategies and multifaceted interventions may be effective for improving vaccination intention against COVID-19.

Association of systemic adverse reaction patterns with long-term dynamics of humoral and cellular immunity after coronavirus disease 2019 third vaccination

The objective of this study was to clarify the impact of adverse reactions on immune dynamics. We investigated the pattern of systemic adverse reactions after the second and third coronavirus disease 2019 (COVID-19) vaccinations and their relationship with immunoglobulin G against severe acute respiratory syndrome coronavirus 2 spike 1 protein titers, neutralizing antibody levels, peak cellular responses, and the rate of decrease after the third vaccination in a large-scale community-based cohort in Japan. Participants who received a third vaccination with BNT162b2 (Pfizer/BioNTech) or mRNA-1273 (Moderna), had two blood samples, had not had COVID-19, and had information on adverse reactions after the second and third vaccinations (n = 2198) were enrolled. We collected data on sex, age, adverse reactions, comorbidities, and daily medicine using a questionnaire survey. Participants with many systemic adverse reactions after the second and third vaccinations had significantly higher humoral and cellular immunity in the peak phase. Participants with multiple systemic adverse reactions after the third vaccination had small changes in the geometric values of humoral immunity and had the largest geometric mean of cellar immunity in the decay phase. Systemic adverse reactions after the third vaccination helped achieve high peak values and maintain humoral and cellular immunity. This information may help promote uptake of a third vaccination, even among those who hesitate due to adverse reactions.

Prevalence and risk factors of adverse effects after the first COVID-19 booster dose: evidence from Greece

Background

In general, COVID-19 vaccines are safe and effective, but minor adverse effects are common. However, adverse effects have not been measured in several countries including Greece.

Objective

To estimate the prevalence of adverse effects after the first COVID-19 booster dose, and to identify possible risk factors.

Material and methods

We conducted a cross-sectional study with a convenience sample in Greece during November 2022. We measured several adverse effects after the booster dose, such as fatigue, headaches, fever, chills, nausea, etc. We considered gender, age, chronic disease, self-assessment of health status, COVID-19 diagnóstico, and self-assessment of COVID-19 course as possible predictors of adverse effects.

Results

In our sample, 96% developed at least one adverse effect. Half of the participants (50.2%) developed one to five adverse effects, 35.9% developed six to ten adverse effects, and 9.5% developed 11 to 16 adverse effects. Mean number of adverse effects was 5.5. The most frequent adverse effects were pain at the injection site (84.3%), fatigue (70.8%), muscle pain (61%), swelling at the injection site (55.2%), headache (49.8%), fever (42.9%), and chills (41%). Females developed more adverse effects than males (p < 0.001). The prevalence of adverse effects of COVID-19 vaccines was statistically significant and positively associated with the severity of COVID-19 among COVID-recovered individuals (p < 0.05). Moreover, younger age was associated with increased adverse effects (p < 0.001).

Conclusions

Almost all participants in our study developed minor adverse effects after the booster dose. Female gender, COVID-19 patients with worse clinical course, and younger individuals experienced more often adverse effects.

Factors Affecting the Public Intention to Repeat the COVID-19 Vaccination: Implications for Vaccine Communication

Although most of the pandemic-related mandatory restrictions have been lifted or eased, vaccination is still recommended as an effective measure to minimize the damage from COVID-19 infection. Since COVID-19 eradication is unlikely, it is necessary to understand the factors affecting the public's vaccination intention when COVID-19 vaccination is continuously recommended. This study aims to explore the factors that affect the intention to repeat the COVID-19 vaccination in South Korea. An online survey was conducted in January 2022 with adults living in Gyeonggi-do, South Korea. In a hierarchical logistic regression analysis, sociodemographic factors, COVID-19 infection-related factors, COVID-19 vaccination-related factors, sociocultural factors, and communication factors were taken into account. In this study, more than three-quarters (78.1%) of Koreans were willing to repeat the COVID-19 vaccination. People who had high-risk perceptions, had been vaccinated against COVID-19 at least once, had more authoritarian attitudes, regarded the vaccination as a social responsibility, and had positive attitudes toward health authorities' regular briefings were more likely to repeat the vaccination. In contrast, those who directly or indirectly experienced COVID-19 vaccine side effects and who showed psychological reactance against the government's vaccination recommendation were less likely to repeat the vaccination. Our research indicates that empathetic communication, promotion of the prosocial aspect of vaccination, and regular and transparent provision of vaccine information are essential for promoting the intention to repeat the COVID-19 vaccination.

Attitudes and concerns regarding booster dose of COVID-19 vaccine among Egyptian patients with autoimmune and rheumatic diseases: a cross-sectional survey study

BACKGROUND

COVID-19 booster dose vaccination acceptance and actual vaccination behavior is not known among Egyptian individuals with autoimmune and rheumatic diseases (ARDs). The aim of this study was to investigate the acceptability of booster dose of the COVID-19 vaccine, as well as the factors that drive and inhibit that acceptance among Egyptian patients diagnosed with ARDs.

METHODS

This interview-based, cross-sectional analytical study was carried out on ARD patients from 20 July to 20 November 2022. A questionnaire was created to assess sociodemographic and clinical data, as well as COVID-19 vaccination status and the intention to receive a COVID-19 vaccine booster dose, perception of health benefits of it in addition to the perceived barriers and/or concerns.

RESULTS

A total of 248 ARD patients were included, with a mean age of 39.8 years (SD = 13.2), and 92.3% were females. Among them, 53.6% were resistant to the COVID-19 booster dose, whereas 31.9% were acceptant and 14.5% were hesitant. Those who were administering corticosteroids and hydroxychloroquine shown significantly greater booster hesitancy and resistance (p = 0.010 and 0.004, respectively). The primary motivation for taking a booster dose among the acceptant group was own volition (92%). Most acceptants believed that booster dose can prevent serious infection (98.7%) and community spread (96.2%). Among the hesitant and resistant groups, the main concerns for booster dose were fear about its major adverse effects (57.4%) and long-term impact (45.6%).

CONCLUSIONS

There is a low acceptability rate of booster dose of COVID-19 vaccine among Egyptian patients with ARD diseases. Public health workers and policymakers need to make sure that all ARD patients get clear messages about accepting the COVID-19 booster dose.

Willingness to receive COVID-19 booster dose and its associated factors in Ghana: A cross-sectional study

Background and Aim

The COVID-19 booster dose has been cited as an important supplement for the control of the COVID-19 pandemic due to reports of waning immunity among fully vaccinated persons. Determining factors that would affect its acceptability is necessary for initiating successful vaccination programs. In this study, we aimed to evaluate the factors associated with the acceptability of the COVID-19 booster dose in Ghana.

Methods

We conducted an online cross-sectional survey among the public. A self-administered questionnaire was used to collect information on demographic characteristics, willingness to vaccinate, perceptions toward COVID-19 vaccines, and trust in the government. Participants provided reasons and sources of advice that may affect their willingness to accept a booster dose. Using IBM SPSS and R Statistic; descriptive, univariate, and multivariate analyses were performed.

Results

Out of 812 respondents, 375 (46.2%) intended to accept the booster dose. Individuals who were males (adjusted odds ratio [aOR] 1.63, 95% confidence interval [CI] 1.07-2.48), had previously received other forms of vaccination twice (aOR 1.96, 95% CI 1.07-3.57) or in most years (aOR 2.51, 95% CI 1.38-4.57), tested positive for COVID-19 (aOR 3.46, 95% CI 1.23-10.52), have high trust in government (aOR=1.77, 95% CI: 1.15-2.74) and had positive perceptions regarding COVID-19 vaccines (OR = 14.24, 95% CI: 9.28-22.44) were more likely to accept a booster dose. Experiencing side effects from the primer dose (aOR 0.12, 95% CI 0.08-0.18) was associated with reduced acceptance. Concerns about vaccine safety and efficacy were the common reasons impeding willingness, while advice from health professionals would be the most considered.

Conclusion

Low intention to accept the booster dose which is associated with a range of factors including the perception of vaccines and trust in the government, is a cause for concern. Thus, more effort would have to be taken through education and policy interventions to increase booster vaccine acceptability.

COVID-19 Vaccine Booster Hesitancy in Malaysia: A Web-Based Cross-Sectional Study

Vaccination is a key public health strategy that is known to be effective in mitigating the risk of infection and severe disease. However, in the context of the COVID-19 pandemic, the percentage (<50%) of Malaysians who have received a booster for the COVID-19 vaccine has remained stagnant over a year. This study aimed to determine the prevalence of and the factors associated with hesitancy toward the second dose of booster for the COVID-19 vaccine. A web-based cross-sectional study was conducted from August to November 2022. The Oxford Vaccine Hesitancy Scale was used to assess the hesitancy toward the second dose of booster for the COVID-19 vaccine. Simple and multiple factors logistic regressions were used to determine the predictors of hesitancy. A p-value less than 0.05 was considered to be statistically significant. Data from 798 respondents were included in the analysis. The prevalence of hesitancy toward the second booster of the COVID-19 vaccine was 26.7%. The predictors of second-booster hesitancy were older age (AOR = 1.040, 95 CI = 1.022, 1.058), having received the third dose (first booster) because of instruction by the government (AOR = 2.125, 95% CI = 1.380, 3.274), concern about serious long term side effects of the vaccine (AOR = 4.010, 95% CI = 2.218, 7.250), and opinions of close friends and immediate family members that the booster is harmful (AOR = 2.201, 95% CI = 1.280, 3.785). Conversely, factors that appear to reduce vaccine booster hesitancy were acceptance of the third dose due to the high number of cases and the increasing rate of infection (AOR = 0.548, 95% CI = 0.317, 0.947), the belief that the vaccine will decrease the risk of getting the infection (AOR = 0.491, 95% CI = 0.277, 0.870), and opinions of close friends and immediate family members that the booster is helpful (AOR = 0.479, 95% CI = 0.273, 0.840). In conclusion, more than one-fifth of Malaysians were hesitant to take the second booster of the COVID-19 vaccine. This suggests that appropriate steps that increase vaccine acceptance, taking into consideration the findings of the present study, are needed to address this issue and to foster more positive attitudes toward vaccination. The survey was available in three main languages but limited to people with internet access; hence, it would likely be biased toward younger adults and social media users and exclude those with limited or no internet access, in particular older people. Therefore, the results are not representative of the Malaysian population at large and caution should be exercised when interpreting the findings.

Factors associated with not receiving the primary series and booster dose of the COVID-19 vaccine among Venezuelan migrants in Peru: A population-based cross-sectional study

BACKGROUND

Ensuring broad COVID-19 vaccination coverage among migrants is a global public health concern. Thus, our study aimed to assess the factors associated with not receiving the primary series and booster dose of the COVID-19 vaccine among Venezuelan migrants in Peru.

METHODS

This was a cross-sectional study based on secondary data analysis of the 2022 Venezuelan Population Residing in Peru Survey. Our population included Venezuelan migrants and refugees over 18 years old living in Peru with complete information for the variables of interest. Two outcome variables were assessed: not receiving the primary series and not receiving the booster dose of the COVID-19 vaccine. Crude and adjusted prevalences were calculated with 95% confidence intervals.

RESULTS

A total of 7,727 Venezuelan adults were included in our study, of whom 6,511 completed the primary series. The overall COVID-19 vaccination coverage of the primary series was 84.17%, whilst the coverage of the booster dose was 28.06%. Being younger, uninsured, illegally-staying, and having a low educational level were associated with both outcomes.

CONCLUSION

Several sociodemographic and migration-related variables were associated with both outcomes. Governmental policies prioritizing vaccination among Venezuelan migrants are needed to ensure broad coverage in this vulnerable group.

Health and Well-Being through COVID-19 Vaccination: Physical, Oral, and Psychological Effects

The Coronavirus Disease 2019 (COVID-19) pandemic and its evolving variants have spurred a worldwide effort to control its transmission and reduce its impact [...].

Effects of Negative Attitudes towards Vaccination in General and Trust in Government on Uptake of a Booster Dose of COVID-19 Vaccine and the Moderating Role of Psychological Reactance: An Observational Prospective Cohort Study in Hong Kong

Uptake of a booster dose of COVID-19 vaccine is effective in preventing infection and severe consequences caused by COVID-19. The present study examined the effects of negative attitudes towards vaccination in general and trust in government on uptake of a COVID-19 booster dose, as well as the moderating role of psychological reactance to pro-vaccination messages in Hong Kong. An observational prospective cohort study using online survey was conducted among 264 adults. Findings showed that, after adjustment for significant background characteristics, negative attitudes towards vaccination in general negatively predicted uptake of a booster dose, and trust in government positively predicted uptake of a booster dose. In addition, the association between negative attitudes towards vaccination in general and uptake of a booster dose was weaker among those who reported a higher level of psychological reactance. The present study highlighted the importance of improving attitudes towards vaccination in general especially among those who are not experiencing psychological reactance, and building trust in government. This study also suggested that interventions aimed at improving attitudes towards vaccination in general should seek to avoid psychological reactance, and special attention should be given to people who are experiencing psychological reactance to pro-vaccination messages.

Predictors of Seasonal Influenza Vaccination Willingness among High-Risk Populations Three Years after the Onset of the COVID-19 Pandemic

High-risk populations are at increased risk of severe influenza-related illness, hospitalization, and death due to influenza. The aim of our study was to assess the willingness of high-risk populations to take the influenza vaccine for the 2022-2023 season, and to investigate the factors associated with such willingness. We conducted a cross-sectional study in Greece in September 2022 using a convenience sample. We considered demographic characteristics, COVID-19-related variables, resilience, social support, anxiety, depression, and COVID-19-related burnout as potential predictors. Among participants, 39.4% were willing to accept the seasonal influenza vaccine, 33.9% were unwilling, and 26.8% were hesitant. Multivariable analysis identified that increased age and increased family support were associated with increased influenza vaccination willingness. Moreover, participants that have received COVID-19 booster doses were more willing to accept the influenza vaccine. In contrast, adverse effects because of COVID-19 vaccination and exhaustion due to measures against COVID-19 reduced influenza vaccination willingness. We found that the intention of high-risk populations to receive the influenza vaccine was low. Our study contributes to an increased understanding of the factors that affect vaccination willingness. Public health authorities could use this information to update vaccination programs against influenza. Emphasis should be given on safety and effectiveness issues.

COVID-19-Related Burnout and Intention of Fully Vaccinated Individuals to Get a Booster Dose: The Mediating Role of Resilience

Because an annual COVID-19 booster vaccine appears to be required to control the pandemic, identifying the factors that influence individuals' decision to receive a booster dose is critical. Thus, our goal was to quantify the influence of COVID-19-related burnout on vaccination intention and to investigate the role of resilience in mediating the link between burnout and intention. We conducted a cross-sectional study with a convenience sample during October 2022. We used the COVID-19 burnout scale and the Brief Resilience Scale. The study sample included 1256 people who had received their primary COVID-19 vaccination. Among the participants, 34.1% reported being very likely to be vaccinated with a booster dose. COVID-19-related burnout was found to be inversely connected with vaccination intention. Moreover, our results suggested that resilience not only had a positive direct effect on vaccination intention but also mediated the relationship between burnout and vaccination intention. Although our study had limitations, such as a convenience sample and information bias, we demonstrate the critical role of resilience in reducing the impact of COVID-19-related burnout on the vaccination intention. Policymakers should develop and implement initiatives to address the issues of COVID-19-related burnout and enhance booster adoption by strengthening psychosocial resources such as resilience.

Drivers of the Intention to Receive a COVID-19 Booster Vaccine: Insights from the UK and Australia

As the global pandemic perpetuates, keeping the population vaccinated will be imperative to maintain societal protection from the SARS-CoV-2 (COVID-19) virus. However, while empirical evidence regarding predictors of the intention to receive a first COVID-19 vaccine has amassed, our understanding regarding the psychological and behavioral drivers of continued COVID-19 vaccination remains limited. In this pre-registered study (UK: AsPredicted#78370|Australia: AsPredicted#81667), factors predicting the intention to receive a COVID-19 booster vaccine were investigated in two adult samples from the UK (N = 1222) and Australia (N = 1197) that were nationally representative on factors of age, gender, and geographic location. High levels of booster intent were found (73% and 67%, respectively). Exploratory Structural Equation Modelling (ESEM) revealed three key predictors of the intention to receive a booster vaccine that emerged across both UK and Australian samples: concern regarding the COVID-19 virus, positive perceptions of the COVID-19 vaccines, and the perceived severity of side effects experienced to the last COVID-19 vaccine dose. Several additional factors (age, months since the last COVID-19 vaccine, familiarity with side effects, and regularly receiving the influenza vaccine) were present in the Australian dataset. These findings provide important evidence that targeting psychological perceptions of the COVID-19 vaccine and virus may serve to maintain participation in the COVID-19 vaccination programme, paving the way for future behavioural research in this area.

COVID-19 Vaccine Booster Dose Acceptance: Systematic Review and Meta-Analysis

The World Health Organization (WHO) recommended coronavirus disease 2019 (COVID-19) booster dose vaccination after completing the primary vaccination series for individuals ≥18 years and most-at-risk populations. This study aimed to estimate the pooled proportion of COVID-19 vaccine booster dose uptake and intention to get the booster dose among general populations and healthcare workers (HCWs). We searched PsycINFO, Scopus, EBSCO, MEDLINE Central/PubMed, ProQuest, SciELO, SAGE, Web of Science, Google Scholar, and ScienceDirect according to PRISMA guidelines. From a total of 1079 screened records, 50 studies were extracted. Meta-analysis was conducted using 48 high-quality studies according to the Newcastle-Ottawa Scale quality assessment tool. Using the 48 included studies, the pooled proportion of COVID-19 vaccine booster dose acceptance among 198,831 subjects was 81% (95% confidence interval (CI): 75-85%, I2 = 100%). The actual uptake of the booster dose in eight studies involving 12,995 subjects was 31% (95% CI: 19-46%, I2 = 100%), while the intention to have the booster dose of the vaccine was 79% (95% CI: 72-85%, I2 = 100%). The acceptance of the booster dose of COVID-19 vaccines among HCWs was 66% (95% CI: 58-74%), I2 = 99%). Meta-regression revealed that previous COVID-19 infection was associated with a lower intention to have the booster dose. Conversely, previous COVID-19 infection was associated with a significantly higher level of booster dose actual uptake. The pooled booster dose acceptance in the WHO region of the Americas, which did not include any actual vaccination, was 77% (95% CI: 66-85%, I2 = 100%). The pooled acceptance of the booster dose in the Western Pacific was 89% (95% CI: 84-92%, I2 = 100), followed by the European region: 86% (95% CI: 81-90%, I2 = 99%), the Eastern Mediterranean region: 59% (95% CI: 46-71%, I2 = 99%), and the Southeast Asian region: 52% (95% CI: 43-61%, I2 = 95). Having chronic disease and trust in the vaccine effectiveness were the significant predictors of booster dose COVID-19 vaccine acceptance. The global acceptance rate of COVID-19 booster vaccine is high, but the rates vary by region. To achieve herd immunity for the disease, a high level of vaccination acceptance is required. Intensive vaccination campaigns and programs are still needed around the world to raise public awareness regarding the importance of accepting COVID-19 vaccines needed for proper control of the pandemic.

Importance of the COVID-19 Vaccine Booster Dose in Protection and Immunity

Background: There is debate on the necessity of booster doses of COVID-19 vaccination, especially in countries with limited resources. Methods: This cross-sectional study was conducted in a referral laboratory in Tehran, Iran. The level of COVID-19 antibodies was measured and compared between individuals regarding the number of COVID-19 vaccine shots. Results: In this study, 176 individuals with a mean age of 36.3 (±11.7) years participated. A total of 112 individuals received two doses of the COVID-19 vaccine, and 64 individuals received three doses. Level of all antibodies was higher in those who received three doses than in those who received two doses of the COVID-19 vaccine. Considering the SARS-CoV-2 Spike IgG, the difference was not statistically significant but for the SARS-CoV-2 RBD IgG and SARS-CoV-2 NAB the difference was statistically significant. Regarding to the background variables, receiving influenza vaccine in the past year, history of autoimmune diseases and past medical history of chicken pox showed a significant association with the number of vaccine doses received. Their effects on the outcome variables assessed with multivariate logistic regression analysis. Conclusion: The results of our study show that a booster dose of the COVID-19 vaccine enhances the antibody response.

COVID-19, Vaccination, and Female Fertility in the Czech Republic

The fast-track process to approve vaccines against COVID-19 has raised questions about their safety, especially in relation to fertility. Over the last 2 years, studies have appeared monitoring female fertility, especially from assisted reproduction centers or in animal experiments. However, studies monitoring healthy populations are still limited. The aim of our study was to monitor the relevant parameters of female fertility (sex and other steroids, LH, FSH, SHBG, Antimüllerian hormone and antral follicle count) before and then 2-4 months after the third dose of vaccination against COVID-19 in a group of 25 healthy fertile woman. In addition, anti-SARS-CoV-2 and anti-SARS-CoV-2S antibodies were determined. We did not observe significant changes in the measured parameters before and after the third dose of vaccination. By comparing levels of the analytes with antibodies indicating a prior COVID-19 infection, we found that women who had experienced the disease had statistically lower levels of estrone, estradiol, SHBG and 5α-dihydroprogesterone, and conversely, higher levels of androgen active dehydroepiandrosterone and dihydrotestosterone. Our results confirm that vaccination does not affect female fertility, and that what fertile women should be worried about is not vaccination, but rather COVID-19 infection itself.

Global Prevalence and Potential Influencing Factors of COVID-19 Vaccination Hesitancy: A Meta-Analysis

Countries worldwide have deployed mass COVID-19 vaccination drives, but there are people who are hesitant to receive the vaccine. Studies assessing the factors associated with COVID-19 vaccination hesitancy are inconclusive. This study aimed to assess the global prevalence of COVID-19 vaccination hesitancy and determine the potential factors associated with such hesitancy. We performed an organized search for relevant articles in PubMed, Scopus, and Web of Science. Extraction of the required information was performed for each study. A single-arm meta-analysis was performed to determine the global prevalence of COVID-19 vaccination hesitancy; the potential factors related to vaccine hesitancy were analyzed using a Z-test. A total of 56 articles were included in our analysis. We found that the global prevalence of COVID-19 vaccination hesitancy was 25%. Being a woman, being a 50-year-old or younger, being single, being unemployed, living in a household with five or more individuals, having an educational attainment lower than an undergraduate degree, having a non-healthcare-related job and considering COVID-19 vaccines to be unsafe were associated with a higher risk of vaccination hesitancy. In contrast, living with children at home, maintaining physical distancing norms, having ever tested for COVID-19, and having a history of influenza vaccination in the past few years were associated with a lower risk of hesitancy to COVID-19 vaccination. Our study provides valuable information on COVID-19 vaccination hesitancy, and we recommend special interventions in the sub-populations with increased risk to reduce COVID-19 vaccine hesitancy.

Higher Collective Responsibility, Higher COVID-19 Vaccine Uptake, and Interaction with Vaccine Attitude: Results from Propensity Score Matching

Providing both personal and social benefits, vaccination may be motivated by collective responsibility (CR). Some previous studies have indicated the relationship between CR and vaccination but could not exclude confounding bias and had little knowledge about the boundary conditions. This study aimed to examine the association between CR and COVID-19 vaccine uptake and its boundary conditions in an extended version of the theory of planned behavior. A cross-sectional survey with 608 participants from six tourism satellite industries in Macao was conducted from 28 July 2021 to 20 August of 2021. Respondentss in CR-lower and CR-higher groups were 1:1 paired using propensity score matching (PSM) to control the potential confounding factors. Results showed participants in the CR-higher group reported significantly higher COVID-19 vaccine uptake than those in the CR-lower group (64.7% vs. 49.7%, p = 0.005). Multivariate logistic regression results indicated a positive association between CR and COVID-19 vaccine uptake (p = 0.012, OR = 2.070, 95% CI= 1.174 to 3.650) and its interaction effect with COVID-19 vaccine attitude (p = 0.019, OR = 0.922, 95% CI = 0.861 to 0.987). Spotlight analysis further illustrated that CR was more effective among individuals with a more negative COVID-19 vaccine attitude. These findings may help promote understanding of vaccine hesitancy, and hence optimize vaccination communication strategies during the COVID-19 pandemic.