Understanding change in COVID-19 vaccination intention with network analysis of longitudinal data from Dutch adults

Motivators and Demotivators for COVID-19 Vaccination Based on Co-Occurrence Networks of Verbal Reasons for Vaccination Acceptance and Resistance: Repetitive Cross-Sectional Surveys and Network Analysis

BACKGROUND

Vaccine hesitancy is complex and multifaced. People may accept or reject a vaccine due to multiple and interconnected reasons, with some reasons being more salient in influencing vaccine acceptance or resistance and hence the most important intervention targets for addressing vaccine hesitancy.

OBJECTIVE

This study was aimed at assessing the connections and relative importance of motivators and demotivators for COVID-19 vaccination in Hong Kong based on co-occurrence networks of verbal reasons for vaccination acceptance and resistance from repetitive cross-sectional surveys.

METHODS

We conducted a series of random digit dialing telephone surveys to examine COVID-19 vaccine hesitancy among general Hong Kong adults between March 2021 and July 2022. A total of 5559 and 982 participants provided verbal reasons for accepting and resisting (rejecting or hesitating) a COVID-19 vaccine, respectively. The verbal reasons were initially coded to generate categories of motivators and demotivators for COVID-19 vaccination using a bottom-up approach. Then, all the generated codes were mapped onto the 5C model of vaccine hesitancy. On the basis of the identified reasons, we conducted a co-occurrence network analysis to understand how motivating or demotivating reasons were comentioned to shape people's vaccination decisions. Each reason's eigenvector centrality was calculated to quantify their relative importance in the network. Analyses were also stratified by age group.

RESULTS

The co-occurrence network analysis found that the perception of personal risk to the disease (egicentrality=0.80) and the social responsibility to protect others (egicentrality=0.58) were the most important comentioned reasons that motivate COVID-19 vaccination, while lack of vaccine confidence (egicentrality=0.89) and complacency (perceived low disease risk and low importance of vaccination; egicentrality=0.45) were the most important comentioned reasons that demotivate COVID-19 vaccination. For older people aged ≥65 years, protecting others was a more important motivator (egicentrality=0.57), while the concern about poor health status was a more important demotivator (egicentrality=0.42); for young people aged 18 to 24 years, recovering life normalcy (egicentrality=0.20) and vaccine mandates (egicentrality=0.26) were the more important motivators, while complacency (egicentrality=0.77) was a more important demotivator for COVID-19 vaccination uptake.

CONCLUSIONS

When disease risk is perceived to be high, promoting social responsibility to protect others is more important for boosting vaccination acceptance. However, when disease risk is perceived to be low and complacency exists, fostering confidence in vaccines to address vaccine hesitancy becomes more important. Interventions for promoting vaccination acceptance and reducing vaccine hesitancy should be tailored by age.

Dynamic predictors of COVID-19 vaccination uptake and their interconnections over two years in Hong Kong

The global rollout of COVID-19 vaccines faces a significant barrier in the form of vaccine hesitancy. This study adopts a dynamic and network perspective to explore the determinants of COVID-19 vaccine uptake in Hong Kong, focusing on multi-level determinants and their interconnections. Following the framework proposed by the Strategic Advisory Group of Experts (SAGE), the study used repeated cross-sectional surveys to map these determinants at multiple levels and investigates their interconnections simultaneously in a sample of 15,179 over two years. The results highlight the dynamic nature of COVID-19 vaccine hesitancy in an evolving pandemic. The findings suggest that vaccine confidence attitudes play crucial roles in vaccination uptake, with their importance shifting over time. The initial emphasis on vaccine safety gradually transitioned to heightened consideration of vaccine effectiveness at a later stage. The study also highlights the impact of chronic condition, age, COVID-19 case numbers, and non-pharmaceutical preventive behaviours on vaccine uptake. Higher educational attainment and being married were associated with primary and booster vaccine uptake and it may be possible to leverage these groups as early innovation adopters. Trust in government acts as a crucial bridging factor linking various variables in the networks with vaccine confidence attitudes, which subsequently closely linked to vaccine uptake. This study provides insights for designing future effective vaccination programmes for changing circumstances.

Understanding public perceptions toward sustainable healthcare through psychological network analysis of material preference and attitudes toward plastic medical devices

Recent and potential future health-care users (i.e., the public) are important stakeholders in the transition toward environmentally sustainable healthcare. However, it remains unclear whether, according to the public, there is room for sustainable innovations in materials for plastic medical devices (PMD). This study explores preferences regarding conventional or bio-based PMD, and psychological mechanisms underlying these preferences. We administered two surveys among Dutch adults from a research panel. Results from the first survey (i.e., open-text survey on attitude elements; NStudy1 = 66) served as input for the second survey (i.e., Likert-scale survey on beliefs, emotions, perceived control, social norms, trust, related to current and bio-based PMD, and health and age; NStudy2 = 1001; Mage = 47.35; 54.4% female). The second survey was completed by 501 participants who, in the last two years, received care in which PMD were used, and 500 participants who did not. Cross-sectional psychological networks were estimated with data from the second study using the EBICglasso method. Results showed that participants preferred bio-based over conventional PMD, and this applied regardless of whether devices are used inside or outside of the body. Results also showed emotions play an important role, with emotions regarding bio-based PMD being strongly related to preference. Furthermore, comparing recent and potential future receivers of PMD revealed differences in preference but comparable relations between preference and other psychological variables. This study shows that receivers' perspectives should not be seen as potential barriers, but as additional motivation for transitioning toward sustainable healthcare. Recommendations for implementation are discussed.

Evolution of preferences for COVID-19 vaccine throughout the pandemic - The choice experiment approach

In this study, we employ a choice experiment to study individual preferences for COVID-19 vaccines in the US. A unique characteristic of the microdata (N = 5671) is that the survey was conducted in five distinct waves from October 2020 to October 2021. Because of this dynamic feature, it is possible to control for evolving pandemic conditions such as the number of COVID-19 active cases, vaccination uptake, and the frequency of Google searches related to the vaccines. Furthermore, we employ a hybrid choice model to incorporate respondents' attitudes related to their perceived vulnerability to diseases, as well as their perceived health status. The hybrid choice model was extended to incorporate latent classes as well as random effects. We find that the rate of vaccinated individuals in the population actually increases the probability of vaccine hesitancy, and therefore may discourage people to get vaccinated. This may be evidence of free-riding behavior. On the other hand, the number of COVID-19 cases has a positive effect on the probability of getting vaccinated, suggesting that individuals react to the pandemic conditions by taking some protective measures. Google trend data do not seem to have a straightforward effect on the vaccination demand, but it increases consumers' willingness to pay for several vaccine characteristics. With respect to the analyzed attitudes, we find that perceived uninfectability is a significant driver of vaccine hesitancy, probably related to the frequent "natural immunity" argument. In turn, germ aversion has a positive effect on the probability of getting vaccinated as well as on the marginal willingness to pay. Finally, health status has a limited effect on whether the individual will decide to vaccinate or not.

How does the vaccine approval procedure affect COVID-19 vaccination intentions?

People's willingness to vaccinate is critical to combating the COVID-19 pandemic. We devise a representative experiment to study how the design of the vaccine approval procedure affects trust in newly developed vaccines and consequently public attitudes towards vaccination. Compared to an Emergency Use Authorization, choosing the more thorough Conditional Marketing Authorization approval procedure increases vaccination intentions by 13 percentage points. The effects of the increased duration of the approval procedure are positive and significant only for Emergency Use Authorization. Treatment effects do not differ between relevant subgroups, such as respondents who had (did not have) COVID-19, or between vaccinated and unvaccinated respondents. Increased trust in the vaccine is the key mediator of treatment effects on vaccination intentions.