Prevalence and factors associated with not receiving the booster dose of the COVID-19 vaccine in adults in Latin America and the Caribbean

Who is getting COVID-19 boosters? A latent class analysis in a nationally representative sample of Mexican adults 60 years and over

OBJECTIVE

Estimate COVID-19 vaccine booster uptake and identify sociodemographic profiles associated with vaccine booster uptake in Mexican adults aged 60 and older.

METHODS

Using data from the 2022 National Health and Nutrition Survey, we estimated COVID-19 booster uptake in Mexican adults 60 and older. We conducted a latent class analysis using sociodemographic characteristics and then estimated group-specific booster prevalence.

RESULTS

Adults aged 60 and older with a completed vaccination schedule had 80.3% booster coverage. Two groups showed the lowest coverage: 1) unemployed and informal working men with elementary education with low socioeconomic status (73.8% boosted), and 2) female homekeepers with elementary education or less living in rural areas (77.0% boosted).

CONCLUSIONS

Our analysis points to the need to reach out to men and women with elementary education or less who live in rural areas to strengthen booster campaigns in the future.

Updated Surveillance Metrics and History of the COVID-19 Pandemic (2020-2023) in Latin America and the Caribbean: Longitudinal Trend Analysis

BACKGROUND

In May 2020, the World Health Organization (WHO) declared Latin America and the Caribbean (LAC) the epicenter of the COVID-19 pandemic, with over 40% of worldwide COVID-19-related deaths at the time. This high disease burden was a result of the unique circumstances in LAC.

OBJECTIVE

This study aimed to (1) measure whether the pandemic was expanding or contracting in LAC when the WHO declared the end of COVID-19 as a public health emergency of international concern on May 5, 2023; (2) use dynamic and genomic surveillance methods to describe the history of the pandemic in the region and situate the window of the WHO declaration within the broader history; and (3) provide, with a focus on prevention policies, a historical context for the course of the pandemic in the region.

METHODS

In addition to updates of traditional surveillance data and dynamic panel estimates from the original study, we used data on sequenced SARS-CoV-2 variants from the Global Initiative on Sharing All Influenza Data (GISAID) to identify the appearance and duration of variants of concern (VOCs). We used Nextclade nomenclature to collect clade designations from sequences and Pangolin nomenclature for lineage designations of SARS-CoV-2. Additionally, we conducted a 1-sided t test for whether the regional weekly speed (rate of novel COVID-19 transmission) was greater than an outbreak threshold of 10. We ran the test iteratively with 6 months of data across the period from August 2020 to May 2023.

RESULTS

The speed of pandemic spread for the region had remained below the outbreak threshold for 6 months by the time of the WHO declaration. Acceleration and jerk were also low and stable. Although the 1- and 7-day persistence coefficients remained statistically significant for the 120-day period ending on the week of May 5, 2023, the coefficients were relatively modest in magnitude (0.457 and 0.491, respectively). Furthermore, the shift parameters for either of the 2 most recent weeks around May 5, 2023, did not indicate any change in this clustering effect of cases on future cases. From December 2021 onward, Omicron was the predominant VOC in sequenced viral samples. The rolling t test of speed=10 became entirely insignificant from January 2023 onward.

CONCLUSIONS

Although COVID-19 continues to circulate in LAC, surveillance data suggest COVID-19 is endemic in the region and no longer reaches the threshold of the pandemic definition. However, the region experienced a high COVID-19 burden in the early stages of the pandemic, and prevention policies should be an immediate focus in future pandemics. Ahead of vaccination development, these policies can include widespread testing of individuals and an epidemiological task force with a contact-tracing system.

Trends in Intention to Take the Second Booster COVID-19 Vaccination and Associated Factors in China: Serial Cross-Sectional Surveys

BACKGROUND

The escalating complexity of the COVID-19 epidemic underscores the need for heightened attention to booster vaccinations. This study aims to examine the changing trend in the public's intention to receive the second COVID-19 booster vaccination over time and the associated factors following the COVID-19 policy optimization in China.

METHOD

Eight cross-sectional surveys utilizing SMS questionnaire links were conducted in Guangzhou, China, from December 2022 to April 2023. The Mann-Kendall test was employed to analyze the trend in intentions to receive the second booster vaccination across the survey time. Adjusted and multivariate logistic analyses were used to analyze the factors associated with vaccination intention. Parallel analyses were performed for two subgroups with different COVID-19 infection statuses.

RESULTS

A total of 9860 respondents were surveyed in the eight rounds, of which 8048 completed the first booster vaccination and were included in the analysis. The overall COVID-19 infection rate was 60.0% (4832/8048), while the overall vaccination intention was 72.2% (5810/8048) among respondents. The vaccination intention exhibited a significant declining trend over time, decreasing from 81.5% in December 2022 to 52.2% in April 2023. An adjusted logistic regression analysis revealed that anxiety and depression were negatively associated with an intention to receive the second booster vaccination, while COVID-19-related preventive behaviors and a high engagement in COVID-19-related information were positively associated with an intention to receive the second booster vaccination. A subgroup analysis revealed that the association between psychological and behavioral characteristics and vaccination intention remained relatively stable among individuals with different histories of COVID-19 infections.

CONCLUSION

There was a significant decline in the intention to receive the second booster vaccination following the optimization of the COVID policy in China. Our findings emphasize the urgency of the second booster vaccination and provide a foundation for the development of tailored interventions to enhance and sustain vaccination intention among the public.

Understanding the factors associated with COVID-19 vaccine hesitancy in Venezuela

BACKGROUND

Despite nearly a quarter of Venezuelans remaining unvaccinated against coronavirus disease 2019 (COVID-19), the factors contributing to vaccine hesitancy in the country have not been thoroughly investigated.

METHODS

A cross-sectional study was conducted from October 15th to 30th, 2022, using a knowledge, attitudes, and practices (KAP) survey to identify factors associated with COVID-19 vaccine hesitancy.

RESULTS

The study analyzed data from 1,930 participants from all 24 states of Venezuela. The majority (93.4%) were vaccinated. The mean age was 40 years, predominantly female (67.3%), and held a university degree (70.6%). The mean KAP score was significantly higher among vaccinated individuals compared to unvaccinated ones (7.79 vs. 3.94 points for knowledge, 40 vs. 24 points for attitudes, and 16 vs. 10 points for practices, all p < 0.001). Increases in the scores for KAP were associated with increased odds of being vaccinated (84.6%, 25.6%, and 33% respectively for each one-point increase, all p < 0.001). Certain demographic factors such as marital status, occupation, religious beliefs, monthly income, and location influence COVID-19 vaccine knowledge. Higher income and certain occupations decrease the odds of low knowledge, while residing in specific states increases it. Attitudes towards the COVID-19 vaccine are influenced by age, health status, vaccination status, and location. Higher income and absence of certain health conditions decrease the odds of negative attitudes. Lastly, age, occupation, monthly income, and location affect vaccine practices. Advanced age and higher income decrease the odds of inappropriate practices, while residing in La Guaira state increases them.

CONCLUSION

Factors such as age, education level, occupation, monthly income, and location were found to be associated with knowledge and attitudes towards COVID-19 vaccine among the surveyed Venezuelans.

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.

Factors associated with intention to be vaccinated with the COVID-19 booster dose: a cross-sectional study in Peru

Introduction

The pandemic of COVID-19 continues to impact people worldwide, with more than 755 million confirmed cases and more than 6.8 million reported deaths. Although two types of treatment, antiviral and immunomodulatory therapy, have been approved to date, vaccination has been the best method to control the spread of the disease.

Objective

To explore factors associated with the intention to be vaccinated with the COVID-19 booster dose in Peru.

Material and Methods

Cross-sectional study, using virtual and physical surveys of adults with two or more doses of COVID-19 vaccine, where the dependent variable was the intention to be vaccinated (IBV) with the booster dose. We calculated prevalence ratios with 95% confidence intervals, using generalized linear models of the Poisson family with robust varying, determining associations between sociodemographic, clinical, and booster dose perception variables.

Results

Data from 924 adults were analyzed. The IBV of the booster doses was 88.1%. A higher prevalence was associated with being male (aPR = 1.05; 95% CI [1.01-1.10]), having a good perception of efficacy and protective effect (PR = 3.69; 95% CI [2.57-5.30]) and belonging to the health sector (PR = 1.10; 95% CI [1.04-1.16]). There was greater acceptance of the recommendation of physicians and other health professionals (aPR = 1.40; 95% CI [1.27-1.55]).

Conclusions

Factors associated with higher IBV with booster dose include male gender, health sciences, physician recommendation, and good perception of efficacy.

A Systematic Review on Sociodemographic, Financial and Psychological Factors Associated with COVID-19 Vaccine Booster Hesitancy among Adult Population

Background: While considerable evidence supports the safety and efficacy of COVID-19 vaccines, a sizable population expresses vaccine hesitancy. As per the World Health Organization, vaccine hesitancy is one of the top 10 hazards to global health. Vaccine hesitancy varies across countries, with India reporting the least vaccine hesitancy. Vaccine hesitancy was higher toward COVID-19 booster doses than previous shots. Therefore, identifying factors determining COVID-19 vaccine booster hesitance (VBH) is the sine qua non of a successful vaccination campaign. Methodology: This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) 2020 standards. A total of 982 articles were pooled from Scopus, PubMed and Embase, while 42 articles that addressed the factors of COVID-19 VBH were finally included for further analysis. Result: We identified factors responsible for VBH and divided them into three major groups: sociodemographic, financial, and psychological. Hence, 17 articles stated age to be a major factor for vaccine hesitancy, with most reports suggesting a negative correlation between age and fear of poor vaccination outcomes. Nine studies found females expressing greater vaccine hesitancy than males. Trust deficit in science (n = 14), concerns about safety and efficacy (n = 12), lower levels of fear regarding infection (n = 11), and worry about side effects (n = 8) were also reasons for vaccine hesitancy. Blacks, Democrats, and pregnant women showed high vaccine hesitancy. Few studies have stated income, obesity, social media, and the population living with vulnerable members as factors influencing vaccine hesitancy. A study in India showed that 44.1% of vaccine hesitancy towards booster doses could be attributed dominantly to low income, rural origin, previously unvaccinated status, or living with vulnerable individuals. However, two other Indian studies reported a lack of availability of vaccination slots, a lack of trust in the government, and concerns regarding safety as factors for vaccine hesitancy toward booster doses. Conclusion: Many studies have confirmed the multifactorial nature of VBH, which necessitates multifaceted, individually tailored interventions that address all potentially modifiable factors. This systematic review chiefly recommends strategizing the campaign for booster doses by identifying and evaluating the reasons for vaccine hesitancy, followed by appropriate communication (at both individual and community levels) about the benefits of booster doses and the risk of losing immunity without them.

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.

Why Some People Are Hesitant to Receive COVID-19 Boosters: A Systematic Review

As the COVID-19 pandemic continues and transitions to an endemic stage, booster vaccines will play an important role in personal and public health. However, convincing people to take boosters continues to be a key obstacle. This study systematically analyzed research that examined the predictors of COVID-19 booster vaccine hesitancy. A search of PubMed, Medline, CINAHL, Web of Science, and Scopus uncovered 42 eligible studies. Globally, the average COVID-19 booster vaccination hesitancy rate was 30.72%. Thirteen key factors influencing booster hesitancy emerged from the literature: demographics (gender, age, education, income, occupation, employment status, ethnicity, and marital status), geographical influences (country, region, and residency), adverse events, perceived benefit/efficacy, perceived susceptibility, perceived severity, prior history of COVID-19 infection, vaccination status, vaccination recommendations, health status, knowledge and information, skepticism/distrust/conspiracy theories, and vaccine type. Vaccine communication campaigns and interventions for COVID boosters should focus on factors influencing booster confidence, complacency, and convenience.

Combined Impact of Omicron Vaccination and Environmental Risk Exposure: A Thailand Case Study

This research aimed to determine the levels of COVID-19 booster dose vaccinations in Thai populations in areas with environmental risk exposure during the Omicron outbreak. Five of twenty provinces in Thailand were selected by assessing environmental risk exposure for study settings. A total of 1038 people were interviewed by a structured questionnaire. The predicting factors of COVID-19 booster dose vaccinations were analyzed by univariate and multivariate analysis. The results showed that 69.4% (95% CI 66.5-72.1) of the population was vaccinated with COVID-19 booster doses. Multiple logistics regression revealed that the female gender (AOR 1.49, 95% CI 1.11-2.00), all age groups from 38 to 60 years old, all education levels of at least secondary school, high income (AOR 1.16, 95% CI 1.15-2.24), populations having experience with COVID-19 infection (AOR 2.27, 95% CI 2.05-3.76), knowledge of vaccine (AOR 1.78, 95% CI 1.11-2.83), and trusting attitude (AOR 1.76, 95% CI 1.32-2.36) were factors among those more likely to take COVID-19 booster dose vaccinations in high-environmental-risk-exposure areas. Therefore, an effective booster dose campaign with education programs to increase attitudes toward booster vaccinations should be implemented for the resilience of COVID-19 prevention and control.

Expert review of global real-world data on COVID-19 vaccine booster effectiveness and safety during the omicron-dominant phase of the pandemic

INTRODUCTION

COVID-19 vaccines have been highly effective in reducing morbidity and mortality during the pandemic. However, the emergence of the Omicron variant and subvariants as the globally dominant strains have raised doubts about the effectiveness of currently available vaccines and prompted debate about potential future vaccination strategies.

AREAS COVERED

Using the publicly available IVAC VIEW-hub platform, we reviewed 52 studies on vaccine effectiveness (VE) after booster vaccinations. VE were reported for SARS-CoV-2 symptomatic infection, severe disease and death and stratified by vaccine schedule and age. In addition, a non-systematic literature review of safety was performed to identify single or multi-country studies investigating adverse event rates for at least two of the currently available COVID-19 vaccines.

EXPERT OPINION

Booster shots of the current COVID-19 vaccines provide consistently high protection against Omicron-related severe disease and death. Additionally, this protection appears to be conserved for at least 3 months, with a small but significant waning after that. The positive risk-benefit ratio of these vaccines is well established, giving us confidence to administer additional doses as required. Future vaccination strategies will likely include a combination of schedules based on risk profile, as overly frequent boosting may be neither beneficial nor sustainable for the general population.