1. Introduction

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged as a global crisis in early 2020 [1]. To control the spread of this virus, non-pharmaceutical interventions (NPIs) such as social distancing, mask-wearing, handwashing, and quarantine were promptly implemented. Despite the effectiveness of these measures in mitigating the immediate spread, they were not sufficient for long-term control of the virus. The need for effective and reliable vaccination strategies was underscored for proactive and sustainable management, as vaccines are crucial not only in are crucial not only in reducing the incidence of cases but also in significantly reducing the risk of hospitalization and death [2–4] The United Kingdom was the first to initiate a COVID-19 vaccination program following the emergency use authorization of the Pfizer-BioNTech vaccine, with other countries including South Korea subsequently launching their vaccination campaigns [2, 5].Nonetheless, COVID-19 vaccination was the most potent and effective means of controlling and preventing COVID-19 [6, 7], COVID-19 vaccine hesitancy had emerged as a significant issue due to concerns about the side effect and effectiveness given the rapid development process [8–12]. Even before the COVID-19 pandemic, the World Health Organization recognized vaccine hesitancy as a major threat to global health and emphasized the need for strategies to enhance public trust and acceptance [13]. Although the pandemic has now transitioned into an endemic phase, the potential for future outbreaks of novel infectious diseases persists. This underscores the continued importance of vaccination campaigns and preparedness for future pandemics. Emergency authorization for vaccines may still be necessary to control new infectious diseases. Therefore, understanding the factors influencing vaccine hesitancy and promoting vaccination is crucial not only for controlling current outbreaks but also for preparing for future pandemics [14–21].

Social cohesion, defined as the degree of connectedness and solidarity among groups within a society, encompasses the perceived sense of community, willingness of neighbors to intervene for the common good, sense of belonging among residents, and the level of trust shared among neighbors [22, 23]. Research indicates that individuals in cohesive and socially integrated communities are more likely to engage in healthy behaviors and experience better health outcomes [24, 25]. This can be attributed to the rapid dissemination of information about health, higher likelihood of adopting healthy behavioral norms, informal social control of health-related deviant behaviors, and the provision of mutual support when necessary [23, 26]. While social cohesion is generally considered a community level characteristic[22, 25, 27], there are limitations to treating it as such due to differences in residents’ perceptions of neighborhood boundaries and variations in their perceptions of the level of neighborhood social cohesion. To address this, some studies examining the relationship between social cohesion and health outcomes have utilized individual-level measurements for social cohesion. In this study, to emphasize the measurement of neighborhood social cohesion at the individual rather than the community level, we use the term "perceived neighborhood social cohesion," as referenced in previous research [24, 28]. Perceived social cohesion has been reported to be associated with influenza vaccination uptake [28], and COVID-19 vaccination intention and uptake [29, 30]. Additionally, perceived social exclusion increased the likelihood of vaccine refusal [31]. These findings highlight the importance of enhancing social cohesion as a strategy to improve vaccination rates and public health outcomes.

However, empirical studies investigating the relationship between perceived neighborhood social cohesion and actual COVID-19 vaccination, rather than vaccination intent, are limited. Additionally, previous research has not sufficiently explored the influence of social cohesion across different age groups. Understanding the impact of neighborhood social cohesion on vaccination behaviors across various age groups is crucial, as differences in social dynamics and health perceptions by age can affect the effectiveness of public health interventions. Identifying these differences can inform the development of targeted strategies to improve vaccination rates and overall public health outcomes.

This study aims to investigate the association between perceived neighborhood social cohesion and COVID-19 vaccination uptake across different age groups. Utilizing a large-scale, nationally representative sample, we controlled for other covariates influencing vaccination rates.

2. Materials and methods

3. Results

The baseline characteristics of the 135,352 participants by age group are presented in Table 1. The 50–64 age group included 66,244 individuals, and the ≥ 65 group 69,108 individuals. In the 50–64 age group, 69.79% expressed trust between neighbors, 52.51% mutual assistance among neighbors, and 75.27% satisfaction with healthcare services in their community. However, in the ≥ 65 age group, these proportions were 79.52%, 69.44%, and 78.85%, respectively, indicating higher levels of perceived neighborhood social cohesion and satisfaction with community healthcare services. In addition, members of the ≥ 65 age group engaged in smoking, drinking, and physical activity less frequently than those in the 50–64 age group.

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Table 1. Baseline characteristics of the participants.

https://doi.org/10.1371/journal.pone.0312309.t001

The characteristics of individuals by vaccination status and the results of the multiple regression analysis are presented in Table 2. In addition, crude odds ratios from the univariate analysis are shown in S1 Table. The crude odds ratios calculated from the univariate analysis of the relationship between vaccination status and each covariate did not differ significantly from the adjusted odds ratios in the multiple regression analysis. Vaccination rates were lower among males than females in the 50–64 age group (92.24% vs. 93.37%), while they were higher among males in the ≥ 65 group (95.21% vs. 94.82%). Participants residing in urban areas, with a higher level of education, higher household income, drinking more frequently, and more engaged in physical activity were more likely to be vaccinated, whereas those living alone, smokers, those who experienced depression, and those who self-rated their health as good were less likely to be vaccinated. Concerns about infection, social stigma, and economic damage due to COVID-19 were positively correlated with vaccination rates, and participants who reported high levels of perceived neighborhood cohesion and satisfaction with healthcare services in their community were also more likely to be vaccinated.

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Table 2. Vacciation status and the results of the complex sample multiple logistic regression analysis.

https://doi.org/10.1371/journal.pone.0312309.t002

Complex sample multiple logistic regression analysis results are provided in Table 2. In the 50–64 age group, factors such as being female, older (within the age group), residing in a rural area, a higher education level, higher household income, and living with family members were significantly associated with higher vaccination rates. Conversely, in the ≥ 65 group, being younger (within the group), living alone, and having a lower education level were significantly associated with higher vaccination rates.

In both groups, smoking (aOR 0.644, 95% CI 0.580–0.714; aOR 0.594, 95% CI 0.497–0.710, respectively) and experience of depression (aOR 0.748, 95% CI 1.0.651–0.860; aOR 0.596, 95% CI 0.515–0.689, respectively) were negatively associated with vaccination rate, while alcohol consumption (aOR 1.552, 95% CI 1.424–1.691; aOR 1.837, 95% CI 1.574–2.144, respectively), physical activity (aOR 1.122, 95% CI 1.012–1.243; aOR 1.516, 95% CI 1.258–1.827, respectively), and good self-reported health (aOR 1.202, 95% CI 1.109–1.303; aOR 1.458, 95% CI 1.291–1.646, respectively) were positively associated with vaccination rate.

In the 50–64 age group, perceived neighborhood cohesion, as assessed by trust between neighbors and mutual assistance among neighbors, was not significantly associated with vaccination uptake. However, in the ≥ 65 group, higher levels of perceived neighborhood cohesion were positively associated with vaccination uptake (aOR 1.200, 95% CI 1.058–1.362 for trust between neighbors; aOR 1.491, 95% CI 1.312–1.695 for mutual assistance among neighbors). In both age groups, satisfaction with community healthcare services was associated with higher vaccination rates (aOR 1.106, 95% CI 1.004–1.219; aOR 1.306, 95% CI 1.160–1.471, respectively). Furthermore, those concerned about social stigma were more likely to be vaccinated in the 50–64 and ≥ 65 groups (aOR 1.344, 95% CI 1.186–1.522; aOR 1.598, 95% CI 1.345–1.900, respectively), whereas concern about economic damage due to COVID-19 was only associated with vaccination in the ≥ 65 group (aOR 1.279, 95% CI 1.079–1.509).

4. Discussion

This study aimed to examine the relationship between perceived neighborhood social cohesion and COVID-19 vaccination status utilizing data from the KCHS (2021), a nationally representative survey conducted annually in South Korea. Notably, findings indicated that among individuals aged ≥ 65, higher perceived neighborhood social cohesion was positively associated with COVID-19 vaccination uptake. However, this association was not observed in the 50–64 age group. The study demonstrates that the relationship between perceived neighborhood social cohesion and vaccination depend on age.

Previous studies have presented several hypothetical mechanisms whereby neighborhood social cohesion might facilitate the use of preventive healthcare services [28]. First, cohesive neighborhoods are more efficient at disseminating information about vaccination procedures including vaccines appointment scheduling and less crowded vaccination sites. Second, cohesive neighborhoods can provide psychological support to individuals with anxiety and concerns about vaccines. Third, cohesive neighborhoods can help establish and maintain healthy norms among community members, and thereby reducing vaccine hesitancy. The results of this study suggest that these mechanisms may be particularly influential in the elderly. Although few studies have studied the relationship between neighborhood social cohesion and vaccination by age, one study suggested that the association between social relationships and vaccination intake increases with age. A study conducted in Germany on adults over 40 found that individuals aged 60–75 who received informational support were more likely to receive influenza vaccinations, while this association was not observed in those aged under 60 [35]. In addition, previous studies that examined relationships between social participation and self-reported health [36], social activities and health-related quality of life [37], and social engagement and experience of depression [38] also indicated that these association were stronger in individuals aged ≥ 65. In addition, a study conducted in the United States exploring quality of social interaction across age groups found that middle-aged adults had the lowest scores for social interaction, while older adults had high positive ratings of their social interaction [39]. These previous studies suggest that perceptions and attitudes towards social relationships and social cohesion are age-dependent and that the influence of these social relationships and social cohesion on health behaviors, such as COVID-19 vaccination, may also depend on age.

The analysis showed that satisfaction with healthcare services in community was associated with higher COVID-19 vaccination rates. This finding is consistent with previous research [17]. Interestingly, in the 50–64 and ≥ 65 age groups, relationships between age, education level, household composition, and vaccination rates showed opposite trends. In the 50–64 group, a higher age (within the group), higher educational attainment, and living with family members were associated with vaccination uptake, whereas in the ≥ 65 group, a lower age (within the group), lower educational attainment, and living alone were associated with vaccination uptake. In a study of the relationship between age and the use of preventive health services, it was observed that influenza vaccination rates increased with age, whereas the probability of cancer screening peaked at 63 [35]. The results of our study demonstrate a pattern similar to previous studies regarding the correlation between cancer screening rates and age. Higher vaccination rates among older age groups may be explained by the risk of fatal consequences associated with COVID-19 infection. However, beyond a certain age, underlying health conditions may prevent individuals from getting vaccinated. In addition, perceptions of the safety and efficacy of COVID-19 vaccinations may depend on age. Such findings suggest that various demographic factors can influence vaccination behaviors in complex ways.

This study also revealed that smoking was negatively associated with vaccination, whereas alcohol drinking was positively associated. A previous study reported negative relationships between influenza vaccination and these health behaviors (both smoking and alcohol drinking) [20]. Both behaviors are considered unhealthy, and thus, individuals who engage in these activities are generally less likely to use preventive health care services, such as health screenings and vaccinations. However, this study shows that higher levels of alcohol consumption were associated with increased COVID-19 vaccination uptake. The Korean government offered vaccination incentives by easing gathering restrictions, and since drinking often occurs in social settings in South Korea [40, 41], this finding suggests that individuals who drank more frequently were more likely to get vaccinated. This indicates that the observed positive correlation between alcohol consumption and vaccination uptake might be due to the unique societal impact of COVID-19 and the incentives offered to encourage vaccination.

The limitations of this study are as follows. First, individuals who did not receive a COVID-19 vaccination due to temporary health-related reasons or problems with vaccination scheduling were not considered, although adjustment was made for self-reported health conditions. In addition, although stable vaccine supply and vaccination implementation were reported for those over 50 at the time of the survey, people who could not get vaccinated at that time due to an accessibility problem but were vaccinated later were not considered. As of October 28, 2022, the first-dose vaccination rate for COVID-19 in Korea was reported to be 90.6% for those aged ≥ 80, 96.2% for those in their 70s, 97.6% for those in their 60s, and 98.0% for those in their 50s [42]. It was difficult to confirm that the partial increase in COVID-19 vaccination rate after the survey was due to aggressive governmental policies encouraging vaccination and the continuous provision of information. In addition, since COVID-19 vaccination supply policy varied by age, caution is needed when interpreting the relationship between age and vaccination uptake. Second, this study employed cross-sectional data, and thus, is limited in terms of its ability to establish causal relationships between vaccination and other factors. However, considering that trust between neighbors, mutual assistance among neighbors, and satisfaction with medical service in neighborhoods are generally stable factors, it is reasonable to infer that these factors had a significant impact on vaccination uptake.

5. Conclusion

This study provides evidence that perceived neighborhood social cohesion significantly influences COVID-19 vaccination uptake among older adults in South Korea, particularly those aged 65 years and older. Our findings underscore that higher levels of social cohesion are positively associated with increased vaccination rates in this demographic, although no such relationship was observed in the younger cohort aged 50–64 years. These results highlight the crucial role of community bonds and mutual trust in influencing the health behaviors of older adults.

The implications of these findings are significant for public health policy. They suggest that enhancing social cohesion could be a strategic approach to increasing vaccination rates, particularly among the elderly, who benefit most from such community support structures. Health policies that incorporate social cohesion initiatives, such as community engagement programs and support networks, could effectively reduce vaccine hesitancy and enhance overall public health security against infectious diseases.

This study proposes further research in several areas. First, the impact of perceived social cohesion on vaccine uptake in younger populations and children needs to be explored. Second, the mechanisms through which social cohesion affects health behaviors across different cultures and community settings require further investigation. Lastly, longitudinal studies are necessary to establish causal relationships and to assess the long-term effects of social cohesion on vaccination behaviors.

In conclusion, our research provides crucial insights into the interplay between perceived neighborhood social cohesion and public health interventions. It advocates for a holistic approach to health policy that considers the social structure of communities as a fundamental component in improving disease prevention efforts, particularly in vaccination campaigns.

Supporting information