At the end of 2020, the COVID-19 pandemic was estimated to have reduced the world’s collective gross domestic product (GDP) by 3.4 percent, equivalent to more than US$2 trillion (1). Current studies suggest that by the end of 2023, the economic impact of the pandemic in the United States alone will reach US$14 trillion (2). A substantial portion of this economic toll stems from the challenges faced by various sectors, including industry and manufacturing.

Romania has encountered multiple successive waves of the COVID-19 pandemic commencing in 2020. The fourth wave, which transpired during the autumn of 2021, was predominantly driven by the Delta variant, thereby resulting in a substantial surge in the incidence of COVID-19 cases, hospital admissions, and fatalities (3). Romania’s vaccination campaign was launched in December 2020, initially focusing on the deployment of mRNA-based vaccines and prioritizing healthcare professionals in hospital environments (4).

The period leading up to May 2021 witnessed the vaccination campaign operating under the constraints imposed by vaccine accessibility. As the pool of individuals voluntarily seeking vaccination diminished, authorities were confronted with the challenges posed by vaccine hesitancy as a prevailing phenomenon. Consequently, targeted interventions became imperative, particularly within specific demographic cohorts exhibiting resistance or hesitancy toward vaccination (4). By September 2021, a total of 5,142,278 individuals in Romania had completed the vaccination regimen with mRNA and viral vector-based vaccines, representing approximately 27.9% of the general population. This low vaccination coverage positioned Romania second to last among European Union countries (5).

Vaccine hesitancy was classified as one of the top 10 global health threats by the World Health Organization (WHO) (6). This phenomenon arose in the context of a broad decline in trust in vaccines, influenced by factors such as the growing impact of the anti-vaccine movement and the reduced visibility of vaccine-preventable diseases. Paradoxically, the success of vaccines has contributed to their own undoing, as some previously eradicated diseases now face the potential of reemergence (7, 8).

Unpublished data from various organizations, including the WHO, in Romania, have highlighted that family doctors and employers are held in higher regard in terms of trust. Consequently, it became apparent that individualized counseling and group facilitation interventions, carried out in the workplace by family doctors and company physicians, could be particularly effective, especially in industrial units where employees from both rural and urban areas converge. When it comes to measure vaccination hesitancy, several methods have been proposed especially for gauging parental hesitancy to vaccinate their children. They were used in the pre-pandemic period (9, 10). Vaccinating adults presents unique challenges, particularly when introducing new vaccines that utilize innovative technologies, all within a context of widespread misinformation surrounding vaccines.

Given the above-mentioned substantial economic costs of the pandemic and its profound impact on industrial production, notably constrained by lockdown measures, the vaccination process has been regarded as one of the vital lifelines required for the sustainable recovery of this economic sector (11). Therefore, it is crucial to identify and quantify the sources of vaccine hesitancy among industrial workers, with the goal of developing strategies to facilitate a sustainable vaccination process. This has become the primary objective of our research, focusing on the validation of a measurement instrument specifically designed to assess vaccine hesitancy within this population group. Future studies will utilize this instrument to develop targeted interventions aimed at addressing vaccine hesitancy and promoting vaccine uptake among Romanian industrial laborers.

The development of the new tool began with the careful formulation of items, ensuring their content validity. The items were developed through a combination of methods, including a comprehensive review of relevant literature, and several rounds of content validity evaluations conducted by experts. This was followed by a thorough scientific examination, which included exploratory factor analysis and an extensive assessment of the instrument’s validity, supported by existing research (12, 13). It is worth noting that the study in question received ethical approval from the Ethics Committee of the University of Medicine and Pharmacy of Craiova, Romania (no. 174/29.10.2021).

In the pilot phase, the initial paper-based questionnaire comprising 20 questions was administered to 30 participants to evaluate the clarity of the items. In the process, three questions employing binary yes/no responses were excluded from the section where the COVID-19 vaccine hesitancy score was calculated. Additionally, ten items formulated in a negative manner were reverse coded to ensure consistency in responses. The participants took between 5 to 10 min to complete the final questionnaire.

This study aimed to create and validate a scale for evaluating concerns related to COVID-19 vaccines. The resultant scale RO-CVH is composed of 15 self-report items on a 5-point Likert scale. The score of RO-CVH describes the level 0f COVID-19 vaccine hesitancy, and significantly predicts COVID-19 vaccination status, assessing the factors influencing the decision for COVID-19 vaccination. Our scale offers a validated approach to understand what factors actively make the decision to receive or not the vaccine: confidence in information regarding the COVID-19 vaccine, safety and efficacy of the COVID-19 vaccine, or the belief that COVID-19 vaccination is a way of controlling the people.

To achieve effective disease control during a pandemic, attaining herd immunity is essential. This immunity can be acquired either through natural infection or through widespread immunization. However, relying on natural infection poses substantial risks, including high mortality rates, overwhelming healthcare systems, and significant disruptions to societal functions. Consequently, immunization emerges as the most viable and strategic approach to mitigating the impact of pandemics, ensuring both public health and societal stability (16). Of particular importance is the impact of illnesses among employees in industry, a phenomenon that causes absenteeism and reduced yields, a fact that has a dramatic impact on the economy and on the quality of life (17).

To obtain herd immunity, a large percentage of the population must be vaccinated. When the level of vaccine hesitancy is high, knowing the reasons behind it becomes very important (11, 16). The role of healthcare workers is pivotal in fostering and maintaining public trust (18).

While instruments exist for assessing knowledge, attitudes, and practices that contribute to adherence to infectious disease control guidelines in COVID-19 (19–21), there remains a critical need to identify and understand the factors driving vaccine hesitancy and reluctance specific for each populational group. Kricorian et al. conducted a nationwide survey in the United States to assess adults’ health literacy regarding the COVID-19 vaccine, as well as their beliefs and experiences related to the virus. However, it is important to note that the instrument used in this study was not fully validated (22). Similarly, other studies were identified that presented various problems regarding their validation (23–25) as well as the general field of application (26).

Our questionnaire demonstrates strong construct validity, offering valuable insights into the underlying factors associated with vaccine hesitancy among adults. Specifically, it focuses on hesitancy related to COVID-19 vaccination and gathers comprehensive data throughout the entire vaccination campaign. Notably, this questionnaire stands as one of the pioneering tools tailored for employees within the industry, making it unique in addressing the active adult population. Its significance lies in its potential to enhance our understanding of the imperative need for vaccination.

This instrument is characterized by its ease of administration, enabling the comparison of knowledge, behaviors, and attitudes among individuals residing in both urban and rural areas. This feature is particularly significant as researching trends within rural populations often presents challenges in identifying barriers (27). A survey conducted in rural Oklahoma found that COVID-19 vaccination hesitancy was significantly influenced by factors such as mistrust in the vaccine’s safety and efficacy, limited access to reliable health information, and strong community-held beliefs, highlighting the need for targeted interventions to address the unique challenges faced by this population (28). Consequently, our questionnaire not only fills a critical gap in the literature but also provides a valuable tool for exploring vaccination attitudes and behaviors, especially among adult populations actively engaged in various industries. Several studies highlight the significant impact of socioeconomic factors on vaccine uptake, even in the presence of detailed vaccination regime and free access to vaccines (29, 30). Also, when taking into account the size of the company a study in Japan identified that second-dose coverage was notably lower among employees of small companies, largely due to fewer employer-arranged vaccination opportunities and socioeconomic factors (31).

The RO-CVH scale provides a valuable tool for identifying and addressing the specific factors driving vaccine hesitancy, such as misinformation, trust in healthcare systems, perceived risks, and workplace culture, to design targeted vaccination campaigns tailored to address specific concerns. Beyond COVID-19, it can inform vaccination efforts for influenza and future outbreaks, ensuring sustainable improvements in vaccine acceptance. As part of our ongoing efforts, we have applied similar tools to investigate influenza vaccine refusal across various populations, considering the values and characteristics of our communities (32).

We acknowledge several limitations in our study. Firstly, the research sample was exclusively drawn from heavy industry entities, leading to a gender distribution disparity with a predominant male presence. Secondly, the rapid progression of vaccination stages, alongside the necessity for urgent professional information intervention within this specific population, restricted the possibility of retesting and comparing the initial results. While this study provides a validated tool to assess COVID-19 vaccine hesitancy among Romanian industrial laborers, it is important to note that the scale primarily focuses on individual-level factors influencing hesitancy, such as perceptions of vaccine safety, efficacy, and trust in health authorities. It does not extensively address systemic issues, including structural barriers to vaccine access (e.g., availability, affordability, and logistical challenges) or the pervasive impact of misinformation and disinformation campaigns. These systemic factors are critical in shaping vaccine hesitancy and uptake, particularly in low-resource or high-misinformation environments. Future research should aim to incorporate these dimensions to provide a more comprehensive understanding of vaccine hesitancy and inform targeted interventions. These constraints should be considered when interpreting the findings of our study.

Our questionnaire serves as a validated and reliable instrument designed to assess vaccine hesitancy among industry workers. This tool is invaluable for employers and medical services within the industry, enabling them to discern the factors contributing to low acceptance rates and vaccine refusals, not only during the COVID-19 pandemic but also in other contexts such as outbreaks or annual influenza vaccinations. By understanding the root causes of vaccine hesitancy, a crucial step in promoting sustainable health practices, tailored interventions can be developed. Optimal vaccination coverage can only be achieved through interventions precisely tailored to the identified causes of hesitancy. Having a validated questionnaire to pinpoint vaccine hesitancy equips us with a practical tool. It allows us to implement targeted interventions and design sustainable policies within industrial settings. These efforts, in turn, can significantly reduce workplace absenteeism, mitigate losses in qualified or highly skilled human resources, thereby positively impacting productivity levels.