Determining the Prevalence and Correlates of COVID-19 Booster Vaccine Hesitancy in the Singapore Population Following the Completion of the Primary Vaccination Series

'Is It Safe? Is it not?' A Youth-Led Photovoice Study of Youth Perspectives of COVID-19 Vaccine Confidence

BACKGROUND

Youth have been uniquely affected by the COVID-19 pandemic. Despite high rates of COVID-19 infection, youth had one of the lowest vaccine uptake rates. Certain characteristics can affect vaccine uptake, such as mental health and substance use, but it is important to understand uptake for an effective response to pandemics.

OBJECTIVE

This study examined the perspectives of youth with mental health or substance use concerns on COVID-19 vaccine confidence, hesitancy and overall COVID-19 vaccine perspectives.

METHODS

Using photovoice, a community-based participatory research method, a sample of 27 youth aged 14-24 years participated in a series of photography workshops and focus groups. Participants submitted final photographs for discussion. Focus groups were recorded, transcribed and thematically analysed.

RESULTS

Four themes were generated: (1) Youth deciphered the vaccine discourse in a changing information landscape; (2) mixed perspectives of families, friends and loved ones influenced the vaccine journey; (3) complex societal influences affected views and decisions around the COVID-19 vaccine; and (4) youth navigated their vaccine journeys through first- and second-hand experiences. The four themes and subthemes highlight the evolution of youth's journeys with the COVID-19 vaccine over the course of the pandemic and into the late-pandemic period.

CONCLUSIONS

Youth with mental health or substance use challenges navigated a complex environment during the COVID-19 pandemic. The wide variety of factors influencing vaccine perspectives should be taken into account in public health messaging and future research on youth vaccine uptake. Youth-led and youth-engaged research can help solicit rich and meaningful perspectives of young people on important public health issues.

PATIENT OR PUBLIC CONTRIBUTION

This was a youth-led study. A youth research analyst conducted the study activities together with the support of a youth advisory group, an adult photographer with lived experience, and a scientific team.

Mixed methods approach to understanding COVID-19 vaccine hesitancy among immigrants in the Chicago

BACKGROUND

COVID-19 vaccine hesitancy has been particularly high among immigrant populations, whose experience is shaped by a history of racism and discriminations, and distrust of the healthcare system. In this study we draw from the Theory of Planned Behavior to examine COVID-19 vaccine hesitancy among immigrants in Chicago.

METHODS

A mixed-methods approach comprising of both focus groups and a health survey was conducted from February to August 2022. Five focus groups were held (N = 35) among Black, Asian and Arab/Palestine participants to understand attitudes and beliefs around the COVID-19 vaccine. Focus groups were analyzed using a modified template approach to text analysis. Based on these findings and themes, we developed a survey that was conducted among 413 immigrants from the mentioned communities. We used hierarchical ordinal regression analyses to examine the relationship between COVID-19 vaccine hesitancy and vaccination status.

RESULTS

Qualitative analysis suggest that the major factors influencing COVID-19 vaccine hesitancy included fear of adverse reactions, misinformation around COVID-19 and the vaccine, negative social norms around vaccination, and external pressure to get vaccinated. From our quantitative analysis we found that 24% of participants were unvaccinated, 5% were partially vaccinated, 32.3% were vaccinated but not boosted, and 39% were vaccinated and boosted for COVID-19. Hierarchical regression models suggest that immigrants who hold negative attitudes and social norms around the COVID-19 vaccine are less likely to vaccinate.

CONCLUSIONS

Understanding vaccine hesitancy among immigrants allows for the creation of culturally and linguistically tailored education that can be utilized to increase vaccine confidence and uptake.

Insights from a community-based survey on factors influencing acceptance and uptake of Paxlovid (nirmatrelvir and ritonavir) as a COVID-19 antiviral medication in Singapore

INTRODUCTION

Antiviral treatment can reduce the burden of COVID-19. But utilisation can be suboptimal, even in a setting like Singapore where it is fully subsidized for those with selected medical conditions and older adults (≥ 50 years). We hence investigated the factors affecting awareness, acceptance, and initiative to request Paxlovid.

METHODS

We assessed the Paxlovid awareness, factors impacting its uptake in a survey conducted from August 2022 to September 2022 through the SOCRATES cohort. Multivariable logistic regression was used to investigate associations between sociodemographics, perceptions, and attitudes with the key study outcomes.

RESULTS

Among respondents to the Paxlovid survey, 54% were aware of Paxlovid. On being provided essential details about Paxlovid, 75% reported they would likely be receptive to taking it if prescribed, and 38% indicated the initiative to request for it if it was not suggested by their doctors. Factors associated with awareness of Paxlovid include aged 40 years old and above, higher education, citing websites as an information source, greater trust in healthcare providers (aOR: 1.65, 95% CI 1.26 - 2.15) and government communications (aOR: 0.69, 95% CI 0.55 - 0.86), and higher perceived risk of COVID-19 infection (aOR: 1.25, 95% CI 1.10 - 1.42). Factors associated with acceptance to take Paxlovid include male gender, citing trust in healthcare providers (aOR: 1.49, 95% CI 1.11 - 1.99) and government communications (aOR: 1.38, 95% CI 1.09 - 1.76), and higher perceived severity of COVID-19 (aOR: 1.23, 95% CI 1.07 - 1.42). Factors associated with initiative to request Paxlovid include male gender, having pre-existing diabetes and higher perceived severity of COVID-19 (aOR: 1.24, 95% CI 1.09 - 1.40). The most common reasons for why respondents might not take Paxlovid were concerns about side effects (64%), concerns about costs (29%), and the perception that COVID-19 is a mild (25%).

CONCLUSION

The majority of our respondents would take Paxlovid if it was prescribed to them, but a much smaller proportion would have the initiative to request for this. Key factors that may influence uptake are COVID-19 threat perceptions, trust in healthcare and government, and perceptions of the drug's side effects and cost.

Access to COVID-19 vaccination by socio-economic status in older Singaporean adults: a population-based cohort study

OBJECTIVES

Socio-economic status (SES) disparities exist in the uptake of COVID-19 vaccination; however, most studies were conducted during the initial pandemic wave when vaccination was less discretionary, limiting generalizability. We aimed to determine whether differences in vaccination uptake across SES strata widened after the removal of vaccination-differentiated measures prior to the rollout of the second boosters, in a nationwide cohort of older Singaporeans at higher risk of severe-COVID-19.

STUDY DESIGN

Retrospective population-based cohort study.

METHODS

Retrospective population-based cohort study of all Singaporeans aged ≥60 years from 22nd February 2021-14th February 2023. Cox regression models controlling for demographics and comorbidities were used to estimate hazard-ratios (HRs) for the uptake of primary vaccination as well as first/second boosters, as recorded in the national vaccination registry, according to SES (housing type).

RESULTS

836,170 individuals were included for completion of a primary vaccine series; 784,938 individuals for completion of the first booster and 734,206 individuals for the completion of the second booster. Differences in vaccination uptake by SES strata were observed (e.g. vaccination uptake in lowest-SES [1-2 room public-housing] versus highest-SES [private housing]: second booster, 47.6% vs. 58.1%; first booster, 93.9% vs. 98.0%). However, relative differences did not markedly widen during second booster rollout when vaccination was more discretionary (e.g. amongst those aged 60-69 years: 0.75 [95% CI = 0.73-0.76] for the first booster; 0.81 [95% CI = 0.79-0.84] for the second booster).

CONCLUSION

While differences in vaccination uptake across SES strata by housing type persisted during the rollout of primary vaccination and subsequent boosters in a nationwide cohort of older Singaporeans, differences did not widen substantially when vaccination was made more discretionary.

Influence of Environmental Risk Exposure on the Determinants of COVID-19 Booster Vaccination in an Urban Thai Population

This study aimed to identify the influence of environmental risk exposure levels on the predictive factors of COVID-19 booster dose vaccination in an urban Thai population in the post-pandemic era. Six study locations, including the three provinces with the highest environmental risk levels and the three provinces with the lowest environmental risk levels, were selected by calculating the environmental risk exposure indexes. Participants from the capital district of each province were chosen via the simple random sampling technique and interviewed using a structured questionnaire. A total of 1315 individuals were included in a sample in this study, and the best predictors of booster dose vaccination were determined using multiple regression analysis. The results showed that a high level of environmental risk exposure occurred in the provinces with a high number of total days exceeding the limits set for PM10 and high rates of mortality for lung cancer. The number of COVID-19 booster vaccinations given amount to 43.4% of the population during the post-COVID-19 pandemic period. Our multivariate analysis indicated that individuals in the working age group (≥25 years old); those with higher education (diploma degree and above); full-time employment (government and private sectors); those with high monthly incomes (≥USD144.1); and those in areas with the lowest risk level of environmental exposure significantly contributed to the number of booster dose vaccinations given during the post-pandemic period. To summarize, the rate of COVID-19 booster dose vaccination acceptance in Thailand was influenced by socio-economic factors with environmental concerns. These findings improve our understating of both the global pandemic and how environmental exposure affects behavioral change patterns and could improve the effectiveness of post-pandemic management.

Different roles of interpersonal trust and institutional trust in motivating older adults to receive COVID-19 vaccines in Singapore

Since the approvals of several vaccines against COVID-19 by the World Health Organization, a large body of research has studied the determinants of individuals' intention to be vaccinated against COVID-19 in a variety of societies. Vaccine intention is a complex construct rooted in the social context that informs the decision-making process. The underlying reasons for older adults' intention to receive the vaccination is even more important to health authorities in societies with large proportions of older adults. In this paper, we interview 27 women over age 55 in Singapore about their COVID-19 vaccine decision-making. Using a social-ecological framework of trust, we identify factors at both individual and institutional levels that build or undermine trust and underlie older women's decisions to receive COVID-19 vaccinations in an authoritarian regime. Findings show that both interpersonal trust and institutional trust contribute to vaccine uptake, however, trust can also contribute to delays in vaccination. Moreover, a sizable minority of respondents report that they were vaccinated not because of institutional trust, but because they felt compelled to do so. The results shed light on directions for future vaccination campaigns.

Factors associated with delayed diagnosis of symptomatic adult COVID-19 cases presenting to primary care: a population-wide study during transition from Delta to Omicron BA.1 in Singapore

Background

During pandemics, avoiding time delay in diagnosing infection is crucial. We evaluated factors associated with delayed diagnosis of symptomatic SARS-CoV-2 infection in a national cohort of adult Singaporeans, during which emergence of the more transmissible Omicron variant shifted pandemic management towards endemicity.

Methods

Retrospective cross-sectional study amongst all adult Singaporeans diagnosed with symptomatic SARS-CoV-2 infection during the transition from Delta to Omicron BA.1 (September 2021-February 2022). SARS-CoV-2 testing was fully subsidised and compulsory for all symptomatic individuals presenting at primary care. Results and demographic information were extracted from national databases. Time to diagnosis was defined as days from symptom-onset to diagnosis (date of first positive SARS-CoV-2 test); dichotomising into no delay (≤24 h from symptom-onset) and delay >24 h. Multivariable logistic regression was utilised to assess factors associated with delay >24 h, and association of delay >24 h with progression to severe COVID-19.

Findings

Of 149,063 Singaporean adults presenting with symptomatic SARS-CoV-2 infection, 75.9% (113,195/149,063) were diagnosed within 24 h of symptom-onset. On multivariable analysis, female gender, older age (>60 years), Chinese (vs. Malay) ethnicity, socioeconomic status (housing type), primary care characteristics, presentation during Omicron BA.1 (vs. Delta), symptom-onset on Friday/Saturday (vs. Monday), and not having completed a primary vaccination series were independently associated with higher odds of delay >24 h. Delay >24 h was independently associated with severe COVID-19 (adjusted odds-ratio, aOR = 1.45, 95% CI = 1.27-1.65, p < 0.001).

Interpretation

At-risk populations (unvaccinated, age >60 years) had higher odds of delay in diagnosis. Delay >24 h in diagnosis was independently associated with severe COVID-19.

Funding

This study was not grant-funded.

The Psychology of COVID-19 Booster Hesitancy, Acceptance and Resistance in Australia

COVID-19 booster vaccinations have been recommended as a primary line of defence against serious illness and hospitalisation. This study identifies and characterises distinct profiles of attitudes towards vaccination, particularly the willingness to get a booster dose. A sample of 582 adults from Australia completed an online survey capturing COVID-related behaviours, beliefs and attitudes and a range of sociodemographic, psychological, political, social and cultural variables. Latent Profile Analysis (LPA) identified three subgroups: Acceptant (61%), Hesitant (30%) and Resistant (9%). Compared to the Acceptant group, the Hesitant and Resistant groups were less worried about catching COVID-19, used fewer official COVID-19 information sources, checked the news less, were lower on the agreeableness personality dimension and reported more conservatism, persecutory thinking, amoral attitudes and need for chaos. The Hesitant group also reported checking the legitimacy of information sources less, scored lower on the openness to new experiences personality dimension and were more likely than the Resistant and Acceptant groups to report regaining freedoms (e.g., travel) and work requirements or external pressures as reasons to get a booster. The Resistant group were higher on reactance, held more conspiratorial beliefs and rated their culture as being less tolerant of deviance than the Hesitant and Acceptant groups. This research can inform tailored approaches to increasing booster uptake and optimal strategies for public health messaging.

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.

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.

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.

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.