In late January 2020, the COVID-19 outbreak rapidly spread, causing global concern (1). China lifted its almost three-year dynamic zero-COVID policy in December 2022, leaving Omicron variants in wide circulation across the country (2). Thereafter, rapid spread of the virus led to increased mental health problems among many people due to fear of getting sick, social isolation and economic uncertainty as well as reduced quality of life (QoL) (3). In addition, lockdowns and other pandemic control measures have resulted in widespread job losses, business closures, and economic hardship for many individuals and communities (4).

Fire service recruits are individuals who receive specialized training to acquire skills and competencies required by the fire service (5). According to relevant regulations and policies in China, the national comprehensive fire and rescue team is open to the community and new entry firefighters are required to participate in a one-year induction training program. If recruits fail the training and assessment, they will be dismissed (6). Fire service recruits undergo technical and operational training as well as training in mental health and stress management (7). The mental health of firefighters has been subject to significant challenges during and following the pandemic. In response to the pandemic, the Chinese government implemented policies and measures to combat COVID-19. As a result, training for fire service recruits occurred within specific premises, from which they were not permitted to leave freely, increased risk of loneliness, depression and fear were possible consequences of this policy (8, 9). Therefore, understanding mental health problems of fire service recruits could help to reduce distress and promote mental well-being for this population.

Fear, an emotion associated with physiological arousal and emotional avoidance of specific stimuli, is linked to clinical phobias and anxiety disorders when expressed in extreme form (10). Previous research (11) estimated the prevalence of fear of COVID-19 was 18, 19, and 33.7% in general population samples from Bosnia and Herzegovina (12), Brazil (13), and Lebanon (14), respectively. Potential widespread public fear brought on by the COVID-19 pandemic could result in severe emotional distress and a variety of coping responses to perceived dangers of infectious disease (15). Moreover, chronic fear can be emotionally exhausting, leading to feelings of helplessness and hopelessness that are characteristic of depression (16, 17). Prolonged activation of stress responses associated with fear and anxiety can also contribute to disruptions in the regulation of stress hormones and affect brain regions involved in mood regulation (18). Other research has found significant associations between higher fear of COVID-19 levels and perceived job insecurity, decreased job satisfaction and poor quality of life (QoL) (19).

Network analysis has emerged as a novel approach to conceptualizing psychological phenomena including fear of COVID-19 (20). Core concepts of network analysis include nodes, that reflect individual symptoms, and edges that represent associations between symptoms (21). Based on network theory, psychological disorders or syndromes can be viewed as networks of interacting symptoms (20). Network models can help to elucidate the most central nodes in a network structure as well as the edges that reflect the strongest relationships between symptoms; such central symptoms serve as plausible targets for prevention or intervention (22).

Network analysis has been applied to numerous mental disorders in samples of the general population (23), adolescents (24), older adults (25), nurses (26), and firefighters (27) during the COVID-19 pandemic. Due to the nature of their work, fire service recruits must learn how to deal with various emergencies including public health crises such as virus outbreaks. Therefore, fire service recruits may be more prone to fear of emergent viruses including COVID-19 compared to the general population. However, to date, no network model of fear of COVID-19 has been evaluated among fire service recruits during or after any virus pandemic, although understanding the pattern of fear and its network structure is important for developing effective psychosocial interventions for those confronted with ongoing and future virus outbreaks.

This study examined the prevalence and correlates of fear of COVID-19 among fire service recruits following the cessation of China’s dynamic zero-COVID policy. In addition, we explored the network structure of COVID-19 fear and identified symptoms having the strongest relationships with QoL.

To our knowledge, this study is the first to examine the prevalence, correlates, and network structure of COVID-19 fear as well as its relationship with QoL among fire service recruits following the cessation of China’s dynamic zero-COVID policy. The prevalence of COVID-19 fear in this sample was 38.85% (95% CI = 36.42–41.32%). This rate was higher than corresponding figures of 18% among residents in Bosnia and Herzegovina (12), and 33.7% for a general population sample in Lebanon (14), each of which used measures with no clear objective cut-off scores. Conversely, the current rate was lower than the rate of 43.8% found within a Hamburg sample of homeless people, based on a single item COVID-19 fear measure (41). Due to study differences in sample characteristics and assessment methods for examining fear of COVID-19, implications based on direct comparisons between these studies should be drawn with caution. However, in the context of their training during the COVID-19 pandemic, fire service recruits have been required to live in a group environment away from their families for an extended period and face strict training assessments that can cause significant stress (42). Our prevalence results align with the meta-analysis finding of a positive relationship between fear of COVID-19 and stress (43).

We found that more severe depression was associated with a higher level of COVID-19 fear among fire service recruits. After the dynamic zero-COVID policy ceased and a full-blown outbreak followed in China, fire service recruits were trained in a lockdown environment. Similarly, previous studies have found a positive correlation between isolation and depression (44, 45). For example, in a study of Turkish adults, fear of COVID-19 was positively correlated with depression (46). The association between depression and COVID-19 fear may be due, in part, to impaired emotion regulation. People who are depressed may experience more emotional dysregulation (47), which contributes to fear by interfering with the capacity to manage emotions effectively as well as increased sensitivity to perceived threats or stressors (48). A study on fear of COVID-19 and psychiatric comorbidities in the United States also reported significant bivariate associations between fear and symptoms of anxiety and depression (49).

We also found that fire service recruits with fear of COVID-19 were more prone to severe physical fatigue. Fire service recruits must undergo long hours of physical fitness and skill training that may be detrimental to their immediate physical and mental well-being. Fatigue refers to a persistent feeling of tiredness that may affect physical and cognitive performance to the point of increasing fear (50, 51). Previous research (52) has highlighted the interplay between cognitive functions and fear. In addition, when people experience fear of COVID-19, they may show heightened stress responding (53) that exacerbates physical fatigue over time (54).

In the network model of fear of COVID-19, “Sleep difficulties caused by worry about COVID-19” (FOC6) in the FCV-19S physical dimension was the most central symptom. Fire service recruits undergo intense training and testing that can cause psychological stress (6, 8). During the pandemic, recruits may be concerned about their own or others’ health, increasing their stress levels and leading to sleep difficulties or other physical and psychological problems (55). The COVID-19 pandemic has led to global uncertainty (56), so fire service recruits may worry about its effects on their jobs, personal lives, and future career development, leading to anxiety and sleep difficulties (57), that may, in turn, lower QOL. Decreased social support associated with quarantine measures may also contribute to feelings of isolation and sleep disturbances (58). The centrality of “Sleep difficulties caused by worry about COVID-19″ in the network structure highlights potential pandemic effects on mental health of fire service recruits, who are particularly susceptible to pandemic-related stressors.

Another central symptom of COVID-19 fear from the FCV-19S physical dimension was “Palpitations when thinking about COVID-19” (FOC7). While palpitations are commonly associated with cardiovascular diseases, previous studies have found that psychiatric disturbances such as panic, anxiety, depression, and somatoform disorders are frequently observed in patients with palpitations (59). Fire service recruits may experience worry about infecting themselves or others, being unable to perform their job effectively or protecting themselves and others. Palpitations are a psychological and physiological response to perceived threats that often emerge in the context of significant life stressors (60). The centrality of “Palpitations when thinking about COVID-19” suggested that physiological symptoms present in severe anxiety states such as panic (61) warrant attention and may be amenable to interventions based on exposure and learning to realistically reappraise specific physiological reactions (62).

“Uncomfortable to think about COVID-19” (FOC2) from the FCV-19S psychological dimension was another central symptom in the network model among fire service recruits, consistent with findings in a study of Latin American countries (63). Worry and stress about viruses such as COVID-19 may lead to physical reactions such as heart palpitations (61), muscle tension (64), upset stomach (65), and fatigue (54) that contribute to more general experiences of discomfort. To ensure the safety and improve well-being of fire service recruits in the context of virus outbreaks or pandemics, it is important to implement a range of measures that include providing comprehensive training and instruction, establishing safety protocols, offering psychological support and promoting physical fitness.

The top three symptoms that were negatively associated with QoL in the flow network model of QoL and Fear of COVID-19 included “Afraid of losing life because of COVID-19” (FOC4) and “Uncomfortable to think about COVID-19” (FOC2) from the FCV-19S psychological dimension and “Sleep difficulties caused by worry about COVID-19” (FOC6) from the FCV-19S physical dimension. After the dynamic zero-COVID policy ceased, Chinese social media was flooded with news about the pandemic; reports of fever and other symptoms were common thereafter. Consequently, many people, including some fire service recruits, may have experienced increased fear of disability or death from COVID-19. While phobias and anxiety disorders are characterized by excessive and persistent worry, fear and apprehension related to external stimuli or bodily sensations (66), death anxiety pertains specifically to fear and distress associated with death and dying (67). Research has contended that fear of death or death anxiety are common and can become more pronounced in situations where mortality risk is prominent (68). Excessive dread of dying can cause psychiatric illnesses and maladjustment (69) that impair QoL (70). Other possible mechanisms underlying death anxiety (71) include regrets about past events and a lack of meaning in life. Fire service recruits will have demanding, risky, psychologically taxing jobs that require long and arduous training to meet required standards. However, during pandemics, the confinement of their training may cause recruits to question the meaning of their lives and their preparedness to meet job demands. A significant negative association between death anxiety and QoL has been shown in previous studies (72, 73).

Strengths of this study included its assessment of a unique, understudied population, and reliable results from the associated network model. However, the research also had several limitations. First, fear of COVID-19 (FCVS-19) was based on a self-report measure and was susceptible to possible response biases (e.g., social desirability bias and recall biases). Second, since this was a cross-sectional study, causal relations between fear of COVID-19 and other factors cannot be demonstrated. Third, to maintain reasonable assessment burdens on unpaid participants, the survey was highly focused and potentially important influences such as workload, personal life characteristics and use of psychotropic medications were not recorded in this study. Furthermore, potentially salient psychiatric conditions such as post-traumatic stress disorder were not assessed and warrant inclusion in future studies. Fourth, specific sources of COVID-19 related fear (e.g., the virus versus vaccines) could not be determined using the FCV-19S.

In conclusion, more than one third of fire service recruits reported fear of COVID-19 after China’s dynamic zero-COVID policy was terminated and a full-blown outbreak followed. Increased fear of COVID-19 was associated with other mental health concerns including elevations in depression, anxiety, pain and physical fatigue in addition to diminished QoL. As the most central symptoms in the network structure of COVID-19 fear, “Sleep difficulties caused by worry about COVID-19,” “Palpitations when thinking about COVID-19” and “Uncomfortable to think about COVID-19” appear to be plausible targets for psychosocial interventions among fire service recruits with heightened fear of COVID-19. Based on the core symptoms negatively correlated with QoL (“Afraid of losing life because of COVID-19,” “Sleep difficulties caused by worry about COVID-19” and “Uncomfortable to think about COVID-19”), maintaining physical and mental health during closed training, improving professional training quality and knowledge (74), keeping in touch with family and friends (75), and participating in recreational activities are viable strategies for helping fire service recruits to maintain or improve their QoL (6).

The data analyzed in this study is subject to the following licenses/restrictions: the datasets presented in this article are not readily available because The Institutional Review Board (IRB) of the China Emergency General Hospital that approved the study prohibits the authors from making publicly available the research dataset of clinical studies. Requests to access these datasets should be directed to Y-TX, xyutly@gmail.com.

The studies involving humans were approved by the ethics committee of China Emergency General Hospital. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

JL: Conceptualization, Data curation, Formal analysis, Funding acquisition, Writing – review & editing. TS: Data curation, Formal analysis, Methodology, Validation, Writing – original draft, Writing – review & editing. PC: Data curation, Methodology, Writing – review & editing. Y-YW: Data curation, Writing – review & editing. ZS: Data curation, Writing – review & editing. TC: Data curation, Writing – review & editing. TJ: Writing – review & editing. Y-TX: Conceptualization, Funding acquisition, Writing – original draft, Writing – review & editing. YF: Conceptualization, Funding acquisition, Writing – review & editing.