Trends in COVID-19 Vaccination Intent, Determinants and Reasons for Vaccine Hesitancy: Results from Repeated Cross-Sectional Surveys in the Adult General Population of Greece during November 2020-June 2021

Changes in general and COVID-19 vaccine hesitancy among U.S. adults from 2021 to 2022

INTRODUCTION

Understanding changes in vaccine hesitancy, overall and by sociodemographic characteristics, may highlight sub-populations for whom more intensive efforts are needed to increase vaccine uptake and confidence.

METHODS

We analyzed data using the CDC's Research and Development Survey (RANDS), a nationally representative survey of U.S. adults ≥18 years, collected from 17 May 2021-30 June 2021 (n = 5,458) and 3 November 2022-12 December 2022 (n = 6,821). We assessed changes in vaccine hesitancy, changes in vaccine attitudes and attitudes, and factors associated with hesitancy toward both vaccines in general and COVID-19 vaccines among a nationally representative sample of U.S. adults.

RESULTS

Although COVID-19 vaccination (≥1 dose) increased from 67.2% (2021) to 74.7% (2022), COVID-19 vaccine hesitancy increased from 40.7% to 44.6% during the same period. During the same period, hesitancy toward both COVID-19 vaccines and vaccines in general increased among those who were aged ≥65 years and who were non-Hispanic White. However, COVID-19 vaccine hesitancy decreased among non-Hispanic Black adults. Current or former smokers were more hesitant toward vaccines in general (aPR = 1.13, 95%CI: 1.03-1.24) and toward COVID-19 vaccines (aPR = 1.08, 95%CI: 1.01-1.16) compared to never smokers. Among adults who did not receive any COVID-19 vaccines, COVID-19 vaccine hesitancy increased from 86.6% in 2021 to 92.4% in 2022. Furthermore, belief in the overall social benefit of the COVID-19 vaccine decreased from 47.5% to 25.1%.

CONCLUSION

This study highlights concerning trends in vaccine hesitancy and uptake of the COVID-19 and other recommended vaccines. We found that some high-risk groups (e.g. smokers) and population subgroups have become more vaccine hesitant, suggesting the need for improved and intensified strategies to increase vaccine confidence and uptake. Future research may focus on qualitative inquiry to understand specific concerns and determinants contributing to increased hesitancy among these groups to help inform interventions and communication campaigns to support vaccination.

Learning from the COVID-19 pandemic: A systematic review of mathematical vaccine prioritization models

As the world becomes ever more connected, the chance of pandemics increases as well. The recent COVID-19 pandemic and the concurrent global mass vaccine roll-out provides an ideal setting to learn from and refine our understanding of infectious disease models for better future preparedness. In this review, we systematically analyze and categorize mathematical models that have been developed to design optimal vaccine prioritization strategies of an initially limited vaccine. As older individuals are disproportionately affected by COVID-19, the focus is on models that take age explicitly into account. The lower mobility and activity level of older individuals gives rise to non-trivial trade-offs. Secondary research questions concern the optimal time interval between vaccine doses and spatial vaccine distribution. This review showcases the effect of various modeling assumptions on model outcomes. A solid understanding of these relationships yields better infectious disease models and thus public health decisions during the next pandemic.

Identifying and overcoming COVID-19 vaccination impediments using Bayesian data mining techniques

The COVID-19 pandemic has profoundly reshaped human life. The development of COVID-19 vaccines has offered a semblance of normalcy. However, obstacles to vaccination have led to substantial loss of life and economic burdens. In this study, we analyze data from a prominent health insurance provider in the United States to uncover the underlying reasons behind the inability, refusal, or hesitancy to receive vaccinations. Our research proposes a methodology for pinpointing affected population groups and suggests strategies to mitigate vaccination barriers and hesitations. Furthermore, we estimate potential cost savings resulting from the implementation of these strategies. To achieve our objectives, we employed Bayesian data mining methods to streamline data dimensions and identify significant variables (features) influencing vaccination decisions. Comparative analysis reveals that the Bayesian method outperforms cutting-edge alternatives, demonstrating superior performance.

Learning from the COVID-19 pandemic: a systematic review of mathematical vaccine prioritization models

As the world becomes ever more connected, the chance of pandemics increases as well. The recent COVID-19 pandemic and the concurrent global mass vaccine roll-out provides an ideal setting to learn from and refine our understanding of infectious disease models for better future preparedness. In this review, we systematically analyze and categorize mathematical models that have been developed to design optimal vaccine prioritization strategies of an initially limited vaccine. As older individuals are disproportionately affected by COVID-19, the focus is on models that take age explicitly into account. The lower mobility and activity level of older individuals gives rise to non-trivial trade-offs. Secondary research questions concern the optimal time interval between vaccine doses and spatial vaccine distribution. This review showcases the effect of various modeling assumptions on model outcomes. A solid understanding of these relationships yields better infectious disease models and thus public health decisions during the next pandemic.

How prevalent is COVID-19 vaccine hesitancy in low-income and middle-income countries and what are the key drivers of hesitancy? Results from 53 countries

OBJECTIVES

This study aims to estimate the levels of COVID-19 vaccine hesitancy in 53 low-income and middle-income countries, differences across population groups in hesitancy, and self-reported reasons for being hesitant to take the COVID-19 vaccine.

METHODS

This paper presents new evidence on levels and trends of vaccine hesitancy in low-income and middle-income countries based on harmonised high-frequency phone surveys from more than 120 000 respondents in 53 low-income and middle-income countries collected between October 2020 and August 2021. These countries represent a combined 53% of the population of low-income and middle-income countries excluding India and China.

RESULTS

On average across countries, one in five adults reported being hesitant to take the COVID-19 vaccine, with the most cited reasons for hesitancy being concerns about the safety of the vaccine, followed by concerns about its efficacy. Between late 2020 and the first half of 2021, there tended to be little change in hesitancy rates in 11 of the 14 countries with available data, while hesitancy increased in Iraq, Malawi and Uzbekistan. COVID-19 vaccine hesitancy was higher among female, younger adults and less educated respondents, after controlling for selected observable characteristics.

CONCLUSIONS

Country estimates of vaccine hesitancy from the high-frequency phone surveys are correlated with but lower than those from earlier studies, which often relied on less representative survey samples. The results suggest that vaccine hesitancy in low-income and middle-income countries, while less prevalent than previously thought, will be an important and enduring obstacle to recovery from the pandemic.

Comprehensive evaluation of the effect of inactivated SARS-CoV-2 vaccination on female fertility: A retrospective cohort study

Fear of possible negative effects of coronavirus disease 2019 (COVID-19) vaccine on fertility is the main reason for vaccine hesitancy among the public especially women of childbearing age. Despite the high coverage of COVID-19 vaccination in China, more scientific evidence is still needed to address their concerns and guide fertility counseling and management in the future. Herein, we performed a retrospective cohort study at a single large center for reproductive medicine in China between August 2020 and May 2023. Patients aged 20-42 years with no history of laboratory-confirmed COVID-19 were included and categorized into different groups according to their vaccination status. The serum sex hormone levels, anti-Müllerian hormone concentrations, embryo quality, and pregnancy outcomes were evaluated and compared among them. We found there were no significant differences in the concentrations of follicle-stimulating hormone, luteinizing hormone and progesterone between the unvaccinated, first-dose, second-dose, and booster vaccinated groups. However, the estradiol showed a highly significant increase in the one-dose vaccinated group compared with its levels in other groups. Among unvaccinated and either vaccinated patients, anti-Müllerian hormone levels were comparable (p = 0.139). The number of oocytes retrieved, fertilization rate and good-quality embryo rate were all similar between each group of in vitro fertilization and intracytoplasmic sperm injection. No significant differences were observed regarding other laboratory parameters. Moreover, the vaccination status of infertile couples did not exert any adverse effect on the pregnancy outcomes in all assisted reproductive technologies cycles. In short, we comprehensively evaluated the reproductive safety of inactivated severe acute respiratory syndrome coronavirus 2 vaccine and found any dose of vaccination wouldn't negatively affect female fertility parameters such as sex hormone levels and ovarian reserve. Moreover, this is the first study to complete the live birth follow-up of the cohort after receiving inactivated severe acute respiratory syndrome coronavirus 2 vaccine, further dispelling the misconception and providing reassurance for decision-making by clinicians.

Socioeconomic Inequalities in COVID-19 Vaccine Hesitancy and Uptake in Greece and Cyprus during the Pandemic

Despite the rigorous investigation of the phenomenon of vaccine hesitancy and refusal during the COVID-19 pandemic, the socioeconomic determinants of this phenomenon remain poorly investigated on a global scale. Following proportional quota sampling, we conducted a population-based cross-sectional study. We recruited participants on-site and online from different settings, regions, and socioeconomic strata in two Eastern Mediterranean populations, Greece and Cyprus. Our approach provided a nationwide sample (n = 576) approaching the adult population structure of the two countries, with a slight underrepresentation of men and older people. Our results indicate clear socioeconomic differences in vaccine hesitancy and vaccination coverage, consistent with wider social inequalities in health. In particular, we reveal a clear socioeconomic gradient characterized by lower vaccine hesitancy and higher vaccination coverage, with increasing educational attainment and income. Additionally, participants residing in semi-urban areas show higher vaccine hesitancy and have lower vaccination coverage than those residing in urban and rural areas. Our results could inform Public Health approaches aiming to tackle the alarming phenomenon of vaccine hesitancy by enabling the targeting of population groups who are particularly vaccine-hesitant, rendering such approaches more targeted and effective while at the same time reducing inequalities in the control and prevention of infectious diseases.

Vaccination Hesitancy Among Greek Orthodox Christians: Is There a Conflict Between Religion and Science?

Since the start of the COVID-19 pandemic vaccines were highly anticipated in order to help contain the spread of the virus and mitigate its impact. However, when the vaccination program began, some minorities were reluctant to get vaccinated for numerous reasons. Specifically, at that time in Greece many priests were opposed to getting vaccinated and proceeded to discourage their flock, in stark contrast to the decisions of Greek Orthodox religious leaders who endorsed the vaccination program. It is clear that the COVID-19 pandemic doesn't solely affect the health system but also other parts of society such as politics, the economy and, last but not least, religion and worship. In the current article, we aim to present the notions and attitudes that led many Greek Orthodox Christians to be hesitant about getting vaccinated or even to become a part of the movement actively against vaccination that has been growing during this pandemic.

Investigating Attitudes, Motivations and Key Influencers for COVID-19 Vaccination Uptake among Late Adopters in Urban Zimbabwe

The rapid development of vaccines in response to the COVID-19 pandemic has provided an effective tool for the management of COVID-19. However, in many African countries there has been a poor uptake of COVID-19 vaccines with only 32.5% first vaccine dose coverage compared to the WHO global target of 70%. As vaccine access improves, one of the important drivers of low uptake has been vaccine hesitancy, driven by levels of confidence, convenience, and complacency. Between 4 January-11 February 2022, we conducted a survey of vaccine late adopters to assess factors that influenced adults in Harare, Zimbabwe to present for their first COVID-19 vaccine dose almost 12 months after the vaccination program began. Of the 1016 adults enrolled, 50% were female and 12.4% had HIV co-infection. Binary logistic regression models were developed to understand factors associated with vaccine confidence. Women were more likely to have negative views about the COVID-19 vaccine compared to men (OR 1.51 (95%CI 1.16, 1.97, p = 0.002). Older adults (≥40 years) compared with youth (18-25 years) were more likely to have 'major concerns' about vaccines. When asked about their concerns, 602 (59.3%) considered immediate side effects as a major concern and 520 (52.1%) were concerned about long-term health effects. People living with HIV (PLWH) were more likely to perceive vaccines as safe (OR 1.71 (95%CI: 1.07, 2.74, p = 0.025) and effective (1.68 (95%CI: 1.07, 2.64, p = 0.026). Internet users were less likely to perceive vaccines as safe (OR 0.72 (95% CI: 0.55, 0.95, p = 0.021) compared to non-Internet users; and social media was a more likely source of information for youth and those with higher education. Family members were the primary key influencers for 560 (55.2%) participants. The most important reason for receiving the COVID-19 vaccine for 715 (70.4%) participants was the protection of individual health. Improving vaccine coverage will need targeted communication strategies that address negative perceptions of vaccines and associated safety and effectiveness concerns. Leveraging normative behavior as a social motivator for vaccination will be important, as close social networks are key influences of vaccination.

Vaccination Coverage and Associated Factors of COVID-19 Uptake in Adult Primary Health Care Users in Greece

In our study, attitudes and perceptions of adult primary health care users regarding COVID-19 vaccination were evaluated. A single-center, cross-sectional study was conducted during a 1-year period (March 2021-March 2022) in a rural area in Crete, Greece. A sample of 626 self-reported questionnaires was collected at the end of the study period. Overall, 78% of respondents stated that they had received the COVID-19 vaccine. The reasons behind vaccine uptake were mainly personal beliefs and the desire to avoid professional constraints. The presence of diabetes type 2, fear of infection, and high perceived efficacy of vaccine previous flu vaccination, living with vulnerable persons, and the influence of scientific information were all significant predictors of COVID-19 vaccine uptake. On the contrary, unwillingness and/or uncertainty to be vaccinated was associated with fear of vaccine side effects, information insufficiency, media/internet information, older age, the presence of inflammatory arthritis, previous COVID-19 infection, the belief that infection confers much greater immunity than the vaccine, and attitudes against vaccinations in general were predictors against COVID-19 vaccination. In conclusion, taking into account all of the above predictors and particularly those regarding safety and vaccine effectiveness may guide future strategies appropriately tailored to specific characteristics and needs of different geographic populations.

COVID-19 vaccine and booster hesitation around the world: A literature review

The development of COVID-19 vaccines has helped limit the extent of the pandemic, which over the past 2 years has claimed the lived of millions of people. The Moderna and Pfizer COVID-19 vaccines were the first to be manufactured using mRNA technology. Since then, other manufacturers have built their own vaccines which utilize adenovirus vector, whole inactivated coronavirus, and protein subunit methods. Given the continued mutation of the SARS-CoV-2 virus, a booster of the COVID-19 vaccine offers additional protection for citizens, especially those with comorbid conditions. However, uptake of the vaccine and booster has faced hurdles. This literature review aims to analyze the acceptance of the COVID-19 booster among different populations throughout the world. Keywords searched include "COVID-19 vaccine rates OR COVID-19 booster rates," "COVID-19 vaccine hesitancy," "COVID-19 booster hesitancy," "reasons against COVID-19 vaccine," "reasons for COVID-19 vaccine," and "COVID-19 vaccine acceptance" (for each country). Research articles indexed in PubMed, University of Illinois Urbana-Champaign Library, and Google Scholar were included. Despite the proven effectiveness of the COVID-19 booster, vaccine hesitancy is still causing suboptimal compliance to the primary vaccine and booster, thus slowing down control of the pandemic. Reasons for vaccine hesitancy differ by country and acceptance is affected by misinformation, political circumstances, and cultural values. Among the most common reasons found are distrust in the government, a lack of safety information, and fear of side effects. Uptake of the COVID-19 vaccine has also been delayed in low and middle income countries due to resource allocation and as a result, these countries have fallen behind vaccination benchmarks. The future of COVID-19 vaccination is unknown, but vaccine mandates and additional booster doses are a possibility. Determining the ethical impact that these policies could have will allow for the best implementation.

Behavioral and Cultural Insights, a Nationwide Study Based on Repetitive Surveys of WHO Behavioral Insights Tool in Greece Regarding COVID-19 Pandemic and Vaccine Acceptance

Monitoring behavioral and cultural insights during the pandemic is a useful tool to identify factors related to COVID-19 vaccine acceptance and confront the pandemic’s vast impact. Data were collected using a questionnaire designed according to the “survey tool and guidance” provided by the World Health Organization (WHO). Surveys were conducted by a market research company for five consecutive months, with a sample of 1000 individuals recruited per survey. Vaccination acceptance increased from 55.2% to 67.2%, while the percentage of undecisive individuals decreased from 16.3% to 10.6%. The proportion of vaccine resistant participants remained relatively steady (25−30%). Knowledge about the pandemic and compliance with preventive measures was high (>90%). Factors associated with vaccination included: Increased age, male gender, influenza vaccination, following authorities’ recommendations, being informed by HCWs or formal information sources, care for others, concern about the country’s economic recession and health system overload. Pandemic fatigue was reflected across the surveys, indicated by a decrease in the intention to self-isolate and remain at home when ill. Despite the decrease of undecisive individuals, a firm core of vaccine resistant individuals may be responsible for the relatively lower vaccine coverage compared to northern EU countries. Study results could be useful for developing approaches tailored to a reluctant population.

Acceptance towards COVID-19 vaccination in Latin America and the Caribbean: A systematic review and meta-analysis

INTRODUCTION

Vaccination represents an important strategy to mitigate COVID-19 related morbidity and mortality by protecting against severe forms of the disease and reducing hospitalization and death rates. In this sense, the objective of this study is to estimate the prevalence of Vaccination Intention (VI) against COVID-19 in Latin America and Caribbean (LAC).

METHODS

We conducted a systematic review with a comprehensive search strategy for the following databases: PubMed, Scopus and Web of Science. A random-effect model meta-analysis was carried out using observational studies assessing the intention to vaccines against COVID-19 in LAC countries. The Clopper-Pearson method was used to estimate 95% Confidence Intervals. The quality assessment was developed using the Newcastle-Ottawa Scale adapted for cross-sectional studies. A subgroup analysis by study location and a sensitivity analysis were developed.

RESULTS

Nineteen cross-sectional studies were included. Five meta-analyzes were performed according to the target population of the included studies. The VI in the general population of LAC was 78.0% (95%CI: 74.0%-82.0%). The VI for non-pregnant women was 78.0% (95%CI: 58.0%-99.0%), for elderly population was 63.0% (95%CI: 59.0%-69.0%), for pregnant women was 69.0% (95%CI: 61.0%-76.0%) and for health-personnel was 83.0% (95% CI: 71.0%-96.0%). The sensitivity analysis for general population meta-analysis that included only low risk of bias studies showed a 77.0% VI (95%CI: 73.0%-82.0%) and for non-pregnant women, 85.0% VI (95%CI: 79.0%-90.0%).

CONCLUSION

Despite the high prevalence of VI in general population found in our study, VI prevalence from elderly people and pregnant women are lower than other population groups and overall population.

Factors Associated with the COVID-19 Vaccination Status of Higher Education Students: Results of an Online Cross-Sectional Survey at Six Universities in Southwestern Germany

This cross-sectional study explored factors associated with the corona virus disease 2019 (COVID-19) vaccination acceptance among higher education students in southwestern Germany. We conducted a cross-sectional online survey at six state-approved higher education institutions (HEIs) between July and November 2021. In addition to descriptive analyses, univariate as well as multivariate binary logistic regression analyses were conducted. A total of 6556 higher education students aged 18 years and older participated in our survey; 91.4% of participating students had been vaccinated against COVID-19 at least once. The factors that significantly contributed to the explanation of higher education students’ vaccination status in the multivariate analysis (area under curve—AUC = 0.94) were variables on the perception of the virus SARS-CoV-2 (affective risk perception: Adjusted odds ratio—aOR = 1.2; perception of the outbreak as a media-hype: aOR = 0.8), attitudes towards personal (aOR = 0.7) and study-related (aOR = 0.8) health and safety measures to prevent transmission of SARS-CoV-2, and attitudes towards COVID-19 vaccination (preservation of own health: aOR = 1.3; confidence in vaccine safety: aOR = 1.7; supporting higher education through vaccination: aOR = 1.2; own contribution to the containment of the pandemic: aOR = 1.7). The findings target assisting HEIs in returning to face-to-face teaching after previous semesters of online teaching.