Abstract
Purpose
COVID-19 devastated communities globally, with the United States leading in fatalities despite extensive control efforts. In 2021, COVID-19 vaccines emerged as the most promising solution, with an efficacy rate exceeding 95% after full vaccination. However, herd immunity remains an elusive target with only 70% of the U.S. population fully vaccinated. This study investigates whether prior vaccination and medical history significantly predict COVID-19 vaccine acceptance and uptake.
Design
Using data collected from the 66th largest U.S. city after the widespread deployment of COVID-19 vaccines and boosters, we employed logistic regression to test whether an individual’s history of vaccination and prior medical engagement positively influence COVID-19 vaccine-related decisions.
Setting
Cross-sectional U.S. survey from July-October 2022 (N = 397) and November 2023-February 2024 (N = 429).
Subjects
Adult Residents of the City of Newark, New Jersey (Aged 18+).
Measures
Newark Community Health Survey (2022, 2023).
Results
Individuals with a history of preventive care, such as attending at least one non-emergency medical visit in the past year, receiving either the pneumococcal or influenza vaccine within the past year, strongly predicted COVID-19 vaccine acceptance. These predictors also demonstrated a strong positive association with the completion of the primary vaccine series and a higher overall total vaccine uptake.
Conclusion
Future vaccine campaigns should prioritize “low engagement” populations who lack both recent routine medical visits and a history of previous vaccinations.
Introduction
Celebrated as one of the most significant scientific breakthroughs of the 20th century, vaccines have a remarkable track record of preventing infectious diseases, reducing mortality and morbidity, and eradicating devastating illnesses (eg, smallpox, polio, measles).1-6 Continuing this legacy, COVID-19 vaccines demonstrated impressive efficacy rates (exceeding 95% after full vaccination), and are poised to be remembered as another historic medical breakthrough.7,8 However, vaccine hesitancy, particularly when it progresses to refusal, significantly hampers public health efforts towards herd immunity.9,10
Defined as “the delay in acceptance or refusal of vaccination despite the availability of vaccination services,”9, p.56 vaccine hesitancy poses a global threat. 11 In the case of COVID-19, a significant portion of the U.S. population refused vaccination due to safety concerns.12,13 This resulted in a significant shortfall in coverage, jeopardizing the goal of herd immunity, which requires an estimated 70% to 80% vaccination rate.14,15 While extensive research has explored vaccine hesitancy, a critical gap remains in identifying reliable predictors of COVID-19 vaccine uptake. Additionally, much of this literature predates the introduction of COVID-19 boosters. Therefore, we examined the association between prior vaccine uptake and non-emergency medical visits as predictors of COVID-19 vaccine acceptance and uptake, using data from New Jersey, one of the most impacted U.S. states (ranking 10th in COVID-19 confirmed cases and 11th in deaths). 16
Literature Review
Decades before the pandemic, Chapman and Coups (1999) published one of the earliest studies on vaccine acceptability, demonstrating that past vaccination behavior shapes individuals’ risk-benefit analysis of future vaccines. 17 In the study, employees who received the influenza vaccine in the previous year were 85% more likely to receive the vaccine in the subsequent year, compared to only 17% among employees without a prior influenza vaccination. 16 Since then, scholars have investigated additional factors influencing vaccine acceptance and uptake.3,10,18-20 However, research conducted outside of a pandemic limits our understanding of how a public health crisis influences vaccine acceptance, particularly in subgroups not previously considered in the existing literature. 21 Furthermore, most COVID-specific studies predate the availability of COVID-19 vaccines and boosters, limiting our ability to assess if intentions translated into action.
To this end, this study focuses on Newark, New Jersey, a city with significant social and economic vulnerability, to test whether medical and vaccine history strongly predicted SARS-CoV-2 vaccine uptake. The City of Newark has a higher proportion of Black and Hispanic residents, foreign-born, and uninsured individuals than state and national averages; subgroups that bore the brunt of the pandemic. 22 Beyond these disparities, the City of Newark accounted for nearly 40% of COVID-19-related deaths in Essex County and 4% in the state.16,23 Given the complex interplay of influencing factors (eg, race, socioeconomic status, health literacy), Newark, New Jersey offered a unique setting to test the study’s hypotheses.
Medical History
According to the Health Belief Model (HBM), the strongest predictors of vaccine acceptance are an individual’s perception of their susceptibility to a disease, the severity of that disease, and a physician’s recommendation.17,19,20,24 Building on this argument, the 5C Model provides a more nuanced framework with five core drivers: confidence, constraints, complacency, calculation, and collective responsibility.3,25 High confidence and a strong sense of collective responsibility generally predict high vaccine acceptance, while structural constraints and complacency often lead to hesitancy. Therefore, we expect individuals with at least one non-emergency medical visit in the last year to exhibit higher COVID-19 vaccine acceptance and uptake. Conversely, we expect individuals who could not afford a medical visit to exhibit lower vaccine acceptance and uptake, as financial barriers reduce exposure to a physician’s guidance. • •
Vaccine History
Nearly 10% of the U.S. population exhibits firm anti-vaccine views, with an additional 40% categorized as vaccine hesitant (having concerns but remaining open to some vaccines).
13
Indeed, despite ranking 1st in COVID-19-related deaths, the U.S. ranked 79th in the percentage of its total population who are fully vaccinated.26,27 Given that past vaccine behavior predicts future acceptance,10,28 and recent research demonstrates that prior influenza and pneumococcal vaccinations are associated with a lower risk of COVID-19 infection, hospitalization, and death,29-31 we hypothesize that individuals who received influenza or pneumococcal vaccines will exhibit significantly higher COVID-19 vaccine acceptance and uptake. • •
Data and Methods
Data Collection
Data for this study were gathered using two waves of the Newark Community Health Survey administered to adult residents in Newark, New Jersey. The survey is part of a public health initiative led by the City of Newark and funded by the U.S. Department of Health and Human Services (HHS). The study protocol was reviewed and approved by the Rutgers University Institutional Review Board (Study ID: Pro2020001641). Prior to participation, respondents were presented with an online informed consent form detailing the study’s purpose, procedures, potential risks and benefits, and participant rights, enabling them to make an informed decision. Adhering to IRB guidelines, we ensured participant anonymity and obtained informed consent from all participants. The datasets were stored in password-protected systems with restricted access, and data will be retained indefinitely in accordance with institutional data management policies.
The survey used an address-based sample (ABS) provided by Marketing Systems Group (MSG), supplemented with an online panel to reach Newark households. MSG’s ABS sampling frame was developed from the U.S. Postal Service Computerized Delivery Sequence File (CDSF), which provides near-complete coverage of residential addresses in Newark, New Jersey. A mail-to-web data collection mode was implemented, whereby invitation letters were mailed to randomly selected households. The first wave was conducted between July and August 2022, and the second wave between January and February 2024 (with fieldwork timing influenced by contracting delays and year-end holidays). Each mailed letter included a QR code and a short URL directing recipients to a self-administered online questionnaire hosted on the Qualtrics platform. Due to low response rates to the mailed invitations (approximately 1 percent), a nonprobability online market research panel was deployed to supplement the ABS sample. Panel respondents were recruited by MSG through the Cint platform in October 2022 for Wave 1 and from November to December 2023 for Wave 2.
Across both waves, the survey yielded 826 completed responses: 397 surveys in Wave 1 (161 ABS and 236 online panel) collected between July and October 2022, and 429 surveys in Wave 2 (83 ABS and 346 online panel) collected between November 2023 and February 2024. The combined dataset integrates both probability-based ABS respondents and nonprobability panel respondents to enhance overall sample size and analytic power.
Measurement
Outcome Variables
We used a binary approach to assess vaccination intention, ensuring a clear differentiation between acceptance and non-acceptance. Participants were asked, “Which of the following best describes your intent to take the recommended COVID vaccinations?” Responses were coded as 0 (no plan to vaccinate) and 1 (vaccinated or intending to vaccinate).
We measured vaccine uptake using primary series completion and total doses received. Primary series completion refers to completing the initial two doses, whereas total doses received captures the cumulative uptake, including boosters. We used two questions to create these variables. First, “Have you had a COVID-19 vaccination?” Responses were coded 0 for “No” and 1 for “Yes.” Second, “How many COVID-19 vaccinations have you received?” Responses ranged from 1 to 4 or more. Combining these questions, we created the variables: total doses received, ranging from 0 (unvaccinated) to 4 or more doses; and primary series completion, with individuals reporting two or more doses coded as 1 and those reporting one dose or less coded as 0.
Predictor Variables
We operationalized vaccine history as receipt of influenza and pneumococcal vaccinations (0 for “No” and 1 for “Yes”). Similarly, medical history was assessed using healthcare affordability and non-emergency doctor visits. Non-emergency visits assessed general engagement with healthcare services in the past year (0 for none, 1 for any). Healthcare affordability was operationalized as a financial barrier to healthcare access. (1 for “Yes,” 0 for “No”). We also included control variables such as age, gender, race, employment status, education, and income (see Appendix for question wording and response categories).
Analysis
Since the first two dependent variables, vaccination intention and primary series completion, are dichotomous, this study estimates these models using logit regression, which is appropriate for binary outcomes. The third dependent variable, total doses received, is measured as an ordered categorical indicator of the number of vaccine doses obtained. Therefore, an ordered logit model is employed to account for the ordinal structure of this outcome. The proportional odds (parallel lines) assumption is assessed using the Brant test. The global test is statistically significant (χ2 = 72.78, P < .001 for the Vaccination History model; χ2 = 63.95, P < .001 for the Medical History model), indicating some departure from the proportional odds assumption. However, violations are confined to a limited subset of covariates, including Age, White race, and survey wave, while the remaining predictors satisfy the assumption.
To address potential violations of the proportional odds assumption, generalized ordered logit models were also estimated, allowing non-parallel effects for variables exhibiting significant constraint violations. However, the fully generalized specification yielded unstable predicted probabilities, as there were 68 in-sample cases producing predicted probabilities below zero. This instability is attributable to the sparse distribution of the outcome variable, whereby only 8.6% of respondents received a single dose of vaccination, the lowest ordered category, resulting in insufficient cell counts to support fully unconstrained parameter estimation.
Given the localized nature of the violations and substantive similarity of estimates, the ordered logit model is retained for parsimony. Findings derived from this model should nonetheless be interpreted with appropriate caution, acknowledging the possibility that the proportional odds assumption may not hold uniformly across all outcome thresholds.
All models include survey-wave and data-source fixed effects to account for systematic differences across the two survey waves and between ABS and panel respondents, including potential variations in sample composition, timing, or contextual factors. Collinearity and overfitting risks were assessed using Variance Inflation Factors (VIFs). VIFs above four warrant investigation; those exceeding ten indicate serious multicollinearity. Our analysis yielded mean VIFs of 1.84 and 1.96, suggesting no significant multicollinearity concerns.
Results
City of Newark Demographic and Vaccination Intentions
The Effects of Vaccination History
Vaccination History Regression Results
95% Confidence Interval in square brackets. ***P < 0.01, **P < 0.05, *P < 0.1.
The Effects of Medical History
Medical History Regression Results
95% Confidence Interval in square brackets. ***P < 0.01, **P < 0.05, *P < 0.1.
Discussion
This study investigated the influence of medical and vaccination history on COVID-19 vaccine acceptance and uptake to inform public health strategies. Focusing on New Jersey, one of the largest cities in the United States, 22 we observed a significant relationship between medical and vaccination history and COVID-19 vaccine uptake. Supporting H3, recent influenza vaccination was positively associated with vaccination intent, primary series completion, and overall uptake. Similarly, supporting H4, pneumococcal vaccination was positively associated with higher likelihoods of primary series completion, intention to receive all recommended doses, and total vaccine uptake. We additionally found strong support for Hypothesis 1. Having at least one non-emergency medical visit within the previous 12 months was positively associated with both COVID-19 vaccine intent and primary series completion. However, we found no support for Hypothesis 2. The inability to afford healthcare services did not correlate with lower vaccination intentions or uptake, suggesting that the U.S. government may have successfully addressed financial cost as a barrier to accessing COVID-19 vaccines.
These findings offer three critical insights that advance existing literature. First, our findings show that recent or COVID-19-adjacent vaccinations alone do not explain COVID-19 vaccine uptake. We found that adherence to the long-established pneumococcal vaccine was significantly associated with COVID-19 vaccine intent and uptake. This suggests that adherence patterns for a long-standing vaccine (pneumococcal) may transfer to novel and even politically charged vaccines (such as COVID-19), particularly during a pandemic. Our findings support Chapman and Coups’ (1999) conclusion that previous vaccination is a strong predictor of future acceptance, as evidenced by the high rates of cumulative and booster uptake in our study. Nevertheless, each new vaccine appears to restart the evaluation process, with the recency of past vaccinations playing a significant role in its continued acceptance.
Second, although our survey did not ask whether COVID-19 was discussed during medical encounters, we observed a positive and significant correlation between having at least one non-emergency medical visit and acceptance and uptake of the COVID-19 vaccine. Indeed, people who attend non-emergency medical visits tend to practice preventive care and are more likely to adhere to science-based solutions. Regardless of the full extent of this effect, the results indicate that a non-emergency medical visit may offset the complex, contextual factors that hinder adherence to healthcare guidelines prevalent in urban settings. The results also strongly indicate the urgent need for greater intervention to address the damaging effects of healthcare employees spreading vaccine myths. Given the growing documentation of COVID-19 vaccine skepticism among healthcare personnel, future efforts must prioritize aligning provider values for COVID-19 vaccines with those of established immunizations (eg, influenza and pneumococcal). If contradictory, these views can have a severe effect on patient behavior, transforming acceptance into hesitancy or accelerating hesitancy into refusal.
A Four-Factor Framework to Understand and Address Vaccine Hesitancy
Concerns Regarding Vaccine Safety and Necessity
Safety concerns were the primary reason for COVID-19 vaccine hesitancy. 32 The novelty and rapid development of SARS-CoV-2 vaccines raised concerns about the adequacy of testing prior to distribution.10,12,18,28 These safety concerns were intensified by pre-existing low trust in government, science, and pharmaceutical entities. Furthermore, inconsistent messaging from public and healthcare officials, such as nurses refusing vaccination, compounded this resistance and diminished institutional credibility. In addition, conspiracy theories alleging a pre-planned pandemic or vaccine-induced infection significantly fueled hesitancy.10,33 In other cases, long-term adverse effects, particularly for vulnerable populations, and prior negative vaccination experiences contributed to hesitancy, refusal, or avoidance. 9 COVID-19 vaccine hesitancy was also driven by a range of individual beliefs regarding necessity, including low health literacy, needle phobia, anti-authority views, the prioritization of philosophical or religious beliefs, and the conviction that asymptomatic infection provided adequate protection.4,10,12,15,20,32.
In light of our findings, we argue that to better meet the unique needs of diverse populations, public health programs should be stratified by healthcare involvement patterns. For individuals without recent medical visits, officials should clearly outline the vaccine development process, testing, and safety profiles. Communication should emphasize that the benefits of COVID-19 vaccination substantially outweigh the potential risks, 34 while acknowledging that rapid deployment was balanced with the understanding that future improvements might be necessary. Furthermore, public health agencies should deploy dedicated teams to counter misinformation on social media, targeting both naive users (including uninsured and underinsured populations) and influential figures whose reach can amplify inaccuracies. In addition, while vaccine mandates may provide short-term boosts,13,39 the results underscore the importance of institutional trust and shared responsibility in maintaining effective public health outreach efforts.35,36,37
Conversely, for individuals with a history of medical engagement or prior vaccination, the focus should shift toward reinforcing institutional trust. Given the pervasive influence of misinformation on health-related decisions, 25 ongoing education for healthcare professionals regarding vaccine safety and necessity is essential.9,19 Empowering clinicians with the latest evidence may mitigate the influence of misinformation during patient encounters. Furthermore, communication should consistently emphasize that the COVID-19 vaccine, mirroring the safety profiles of other established vaccines, is a scientifically robust and safe pathway toward achieving population-level immunity.
Concerns Regarding Vaccine Effectiveness and Affordability
Effectiveness concerns center around three critical questions: First, do COVID-19 vaccines effectively prevent infection, hospitalization, and death?12,14,18,21 Second, what is the duration of vaccine-induced immunity?4,24 Third, what is the long-term effectiveness of these vaccines? 11 In addition, healthcare or vaccine costs presented significant financial burdens, further hindering vaccine acceptance.1,12,32 For example, Reiter et al (2020) showed that cost is a major constraint, with 65% of participants preferring a vaccine priced at $50 or less, and 30% indicating they would rather pay nothing. This demonstrates that cost is a separate barrier distinct from concerns about effectiveness, necessity, or safety. Therefore, to prevent logistical and financial factors from becoming major barriers to access, public and healthcare officials should prioritize providing affordable, preferably free, vaccines. Furthermore, to increase COVID-19 vaccine acceptance among risk-calculating groups questioning vaccine effectiveness, officials should emphasize the rigorous testing and stringent safety standards to which all vaccines are held. 38 Public health officials are also encouraged to highlight how newer vaccines, including the COVID-19 vaccine, build on this legacy by discussing the similarities and differences between the COVID-19 vaccine and other commonly administered vaccines.
Implications and Future Research
What are the broader implications of these findings beyond the specific case presented? Collectively, this study demonstrates that adherence to public health measures and a history of preventive care are intrinsically linked. Compliance is not merely a response to the sudden introduction of a new vaccine or the imposition of mandates. Rather, it is rooted in a pre-existing belief system that views science and medicine as instruments for collective well-being. This means that people who follow health guidelines tend to have a history of following other health recommendations. These positive experiences foster a deeper trust in science, increasing their willingness to embrace new health measures.
This points to a two-fold strategy for public health practitioners in future practice. First, healthcare professionals must ensure that patient interactions are consistently positive, particularly when introducing medical innovations. Transparency about the capabilities and limitations of medical interventions is also vital, because once trust is broken, people may fall into a pattern of avoiding preventive care and seeking medical help only when necessary. Second, health communication must shift from a “reactive” crisis-based model to a more proactive approach to information sharing. Relying on emergency periods or a global crisis to discuss the value of vaccination is counterproductive. Instead, health officials should leverage the four-factor framework to develop continuous educational curricula that bridge the gap between established medical practices and novel technologies. This can effectively reduce general distrust, address hesitancy, and encourage questions that help overcome refusal or skepticism. This is grounded in the fact that, when vaccine education is tied exclusively to a crisis, it can appear as though the incentives are detached from the public’s best interests.
Finally, it is critical to identify the unique reasons for vaccine acceptance and refusal. As previous research and this study demonstrate, past behaviors shape future vaccine intake. Therefore, future research should explore the underlying drivers of vaccine refusal, hesitancy, and acceptance. Understanding these distinct motivations is a prerequisite for effectively expanding the number of people who practice preventive care in U.S. cities or abroad.
Conclusion
This study addresses a critical question regarding COVID-19 vaccine acceptance and uptake: Does an individual’s prior medical and vaccination history influence future vaccine-related decisions? Drawing on the principles of the HBM and the 5C Model, we found that individuals with at least one non-emergency medical visit in the last year, and those who received the pneumococcal and influenza vaccines, were significantly more likely to report intention to receive the COVID-19 vaccine, complete the primary series, and report a higher overall total vaccine uptake. This suggests that vaccine adherence patterns for long-standing inoculations can be transferred to novel and politically charged vaccines, demonstrating that vaccine acceptance is not solely tied to recent or disease-related inoculations (eg, flu), and that recent, non-emergency medical visits can significantly improve COVID-19 vaccine acceptance. Therefore, we argue that future vaccination campaigns should target and prioritize individuals with less recent medical engagement and a history of past vaccinations, as these are strong predictors of hesitancy. We also provide a four-factor framework to guide future efforts in addressing COVID-19 vaccine hesitancy and refusal in American cities.
However, to fully contextualize these findings and the resulting framework, several limitations must be addressed. First, this study is limited by its geographic focus on a single U.S. city, which may restrict the generalizability of the findings to other regions. Second, the study’s cross-sectional design precludes the establishment of definitive temporal ordering or causal inferences. Third, the use of self-reported data is subject to inherent recall and social desirability biases, as well as self-selection into the survey sample. Finally, the use of a mixed sampling design that combines address-based sampling (ABS) with a nonprobability online panel may introduce selection bias, and the low ABS response rate (approximately 1 percent) raises concerns about nonresponse bias. Considered collectively, these limitations suggest that the results should be interpreted as evidence of robust associations rather than definitive causal effects. Future research should address these limitations by employing longitudinal designs, strengthening probability-based sampling, and incorporating validated or administrative data sources to improve both causal inference and measurement accuracy. The literature demonstrates that vaccine hesitancy significantly impedes progress toward achieving COVID-19 herd immunity, and that vaccine acceptance is influenced by a complex interplay of factors, including an individual’s sense of collective responsibility, past vaccine behaviors (specifically, the flu vaccine), and medical intervention. The study demonstrates that vaccine uptake is not merely driven by recent or disease-adjacent inoculations (such as the flu vaccine). Adherence patterns established through long-standing vaccination habits can transfer to novel and politically charged vaccines, particularly during a pandemic. It also provides evidence that recent non-emergency medical visits can significantly increase acceptance and uptake of the COVID-19 vaccine. Furthermore, this study introduces a four-factor framework to guide targeted efforts in mitigating vaccine hesitancy and refusal. Vaccine interventions should move beyond a one-size-fits-all approach. To maximize impact, future vaccine campaigns should prioritize individuals who lack recent routine medical visits and current immunization records, as past vaccinations significantly predict COVID-19 vaccine uptake, and clinical encounters may offer a critical opportunity to initiate a cognitive shift toward vaccine acceptance.So What?
What is Already Known About This Topic?
What Does This Article Add?
What are the Implications for Health Promotion or Research?
Footnotes
Ethical Considerations
This study was approved by the Rutgers University Institutional Review Board (Study ID: 2022000255).
Consent to Participate
Informed consent was obtained from all individual participants included in the study.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the funding for this research project was provided by the U.S. Department of Health and Human Services. Office of Minority Health. 1 CPIMP211242-01-00.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
