**1. Introduction**

The highly infectious coronavirus SARS-CoV-2 caused an epidemic of acute respiratory syndrome (COVID-19). Between January and April 2020, the epidemic turned into a global pandemic, having spread to most countries around the world [1]. In March 2020, the World Health Organization made the assessment that COVID-19 was as a pandemic. In Poland, the COVID-19 pandemic began on 4 March 2020, and on 5 October 2020 the number of people infected with SARS-CoV-2 had risen to 102,080; of those, 2659 died. The outbreak of the coronavirus disease caused intense stress amongst the public in Poland, and healthcare personnel were one of the most affected groups. Since the outbreak, healthcare personnel have found themselves on the frontline in combating COVID-19, working with an increased workload in terms of working hours and patient numbers and facing the highest risk of infection. Thus, operating under such conditions may have contributed to increased psychological stress, with immediate and perhaps long-term psychological consequences [2].

There have as yet been few studies on the psychological effects of working in a healthcare setting around COVID-19. Research conducted in China showed that after the COVID-19 outbreak, medical staff experienced emotional stress, depression, insomnia, and anxiety [2–4]. Nurses and frontline healthcare workers reported more severe degrees of all measurements of mental health symptoms than other healthcare personnel [3]. Although the psychological effects of outbreaks of COVID-19 disease on healthcare personnel have been demonstrated [2–4], little is known about the combined roles of risk perception and individual resources for well-being, and the mediating effects of coping on their relationships. These factors have also not been studied together in healthcare workers. Thus, it is important that these relationships are examined, because the findings may shed more light on specific factors that contribute significantly to the creation of new intervention programs (e.g., meaning-based approaches that address existential distress and psychological well-being). Healthcare personnel need to protect the well-being of themselves and their colleagues to avoid adverse outcomes for both healthcare workers and patients.

#### *1.1. Risk Perception, Meaning-Based Resources, and Psychological Well-Being*

Appraisal-based and resource-based stress theories have been successfully employed in predicting a range of stress outcomes in health contexts [5,6]. Appraisal-based theories, which include the protection motivation theory (PMT), describe how people assess a threat's probability [7], whereas resource-based theories, amongst which the conservation of resources (COR) theory is one of the most prominent, indicate that personal resources enable people to cope effectively with the threat [8].

Protection motivation theory has been successfully applied in the context of health threats to explain the effects of fear on people's reactions and attitudes [7]. It emphasizes the importance of risk perception, which consists of three components: (1) perceived risk of contracting, which is the person's expectation of being exposed to the threat, such as being infected by COVID-19; (2) fear, which plays an indirect role in threat appraisal by affecting the estimation of the danger's severity; and (3) perceived threat, which is the person's estimation of how harmful the consequences of the threat would be to objects they value if the threat were to actually occur (e.g., the judgment that a COVID-19 infection would harm valued things, such as personal health or the health of other people) [9]. Previous studies indicated that perceived risk was negatively related to well-being during the outbreak of severe acute respiratory syndrome (SARS). Research conducted on SARS survivors demonstrated that their subjective interpretation of the infection was related to the level of psychological adjustment measured in terms of emotional distress and perceived health [10]. The few studies carried out so far during the outbreak of COVID-19 amongst the Chinese public revealed that perceived threat was related to a number of undesirable emotional reactions (e.g., an increase in negative emotion) [3] and that self-control moderates the association between perceived threat and mental health problems amongst the Chinese public [11]. Both studies led to the conclusion that the perceived threat of COVID-19 may negatively influence mental health outcomes.

Conservation of resources theory begins with the tenet that individuals strive to obtain, retain, foster, and protect personal resources, defined as "those entities that either are centrally valued in their own right, or act as means to obtain centrally valued ends" [8] (p. 307). The fit of personal resources with external demands determines the direction of stress response and resultant outcomes [5]. Research has demonstrated that resources influence people's abilities to impact their environments successfully, and thus they are typically linked to well-being, positive coping, and global resistance to stress [12]. The studies examining relationships between resources and well-being involve a number of distinctive types of resource [8], among which meaning based resources, e.g., meaning in life (MIL) and existential mattering, are widely studied.

Meaning in life (MIL) has been regarded as a key resource for both coping processes and psychological well-being [13,14]. Meaning in life has been defined as "the extent to which one's life is experienced as making sense, as being directed and motivated by valued goals, and as mattering in the world" [15] (p. 205). Considering the predictive role of MIL on people's psychological health [16–18], examining MIL levels amongst healthcare staff is relevant for many reasons. Meaning in life in healthcare settings plays a vital role in the construction of the individual's identity, and it can provide one of the main sources of inner harmony [19]. In addition, MIL can noticeably influence the ways in which healthcare workers deal with stress and maintain their professional efficiency [20]. Given that

the pandemic is considered a prolonged stressful condition, particularly for those who are in the front line in the fight against the virus, the availability of meaning-based resources would help to manage such stress successfully.

Another factor related to meaning-based resources is existential mattering, which has received a considerable deal of empirical attention in recent years [21,22]. This may be described as one's experiences of value, worth, and transcending everyday life conditions, and is regarded as a core dimension of meaning structures in addition to more commonly accepted significance and purpose [23]. Research has demonstrated that mattering is beneficial to developing self-identity, self-concept, sense of belonging, and understanding one's purpose in life [21]. By developing a sense of mattering in their lives, individuals can gain an awareness of being able to make a difference in the world and to lead a valuable life. Mattering was also found to play a crucial role in psychological well-being and health amongst college and university students [24].

The inclusion of meaning-based resources noticeably influenced psychological models of stress and coping due to the internal structures of purpose and value embedded in the resources. They tend to affect the ways in which important events are perceived as well as how these events are managed [20,25]. Being related to different measures of well-being, they are also likely to affect one's coping responses to stressful events (e.g., public health threats or unpredictable infections).
