The H1N1 influenza, caused by the H1N1 influenza virus, is a highly contagious acute respiratory disease with a seasonal prevalence. It poses a substantial burden on public health, leading to high hospitalization rates and significant morbidity and mortality (Moghadami, 2017). The winter months are characterized by a peak in H1N1 influenza cases, particularly affecting vulnerable populations such as children and the elderly, resulting in a considerable disease burden globally. From the 2010–2011 to 2013–2014 influenza seasons, influenza-related respiratory and circulatory deaths ranged from 12,000 to 56,000, and from 4,000 to 12,000 in the six seasons from 2010–2011 to 2015–2016 (Rolfes et al., 2018). The H1N1 influenza epidemic has caused an unexpected surge in morbidity and mortality rates, thereby increasing the demand for healthcare services (Losier et al., 2023). Consequently, there has been an intensified strain on healthcare systems due to the rapid influx of patients, resulting in a decreased nurse-to-patient ratio and an elevated workload (Jia et al., 2023). The COVID-19 pandemic has shed light on the mental health challenges faced by healthcare workers, revealing a higher prevalence of post-traumatic stress disorder (PTSD) among individuals working long hours, in isolation wards, and particularly among female nurses (Qi et al., 2022).

The emergency department serves as a critical gateway for admitting and providing care to critically ill patients. Due to the unique nature of their work and the environment they operate in, emergency department nurses are frequently exposed to traumatic or stressful events, placing them under greater psychological pressure compared to other groups and making them more susceptible to physical and mental health issues (Caruso et al., 2021). During the winter H1N1 influenza season, the overwhelming influx of patients places significant strain on the healthcare system, particularly impacting emergency department nurses (Schuster and Dwyer, 2020). PTSD is a prevalent psychological distress experienced by emergency department nurses following exposure to highly stressful events. The nature of emergency nursing involves caring for patients with diverse medical conditions, many of whom are critically ill, have complex diseases, and require urgent treatment. Emergency nursing staff often work under heavy workloads for prolonged periods without adequate time to recover physically and mentally. This continuous exposure to traumatic events in the workplace can trigger the development of mental symptoms, leading to the onset of PTSD (Winnand et al., 2023). The consequences of PTSD among emergency department nurses are far-reaching, as it can diminish their caregiving abilities, increase the occurrence of nursing errors, and amplify the desire to leave the profession, thereby impacting the overall quality and safety of clinical care. Consequently, conducting risk assessments and implementing early interventions for PTSD among emergency department nurses are of significant importance (Ramachandran et al., 2023).

Occupational burnout, coping style, psychological resilience and social support are important factors affecting mental health. The characteristics of high intensity, high pressure and high risk of clinical nursing work make nurses a high-risk group of occupational burnout (Kaplan, 2021). Burnout, coping styles, resilience and social support are important factors affecting mental health. The high intensity, high pressure and high-risk characteristics of clinical nursing work make nurses a high-risk group of job burnout (Sipos et al., 2024). Although numerous studies have focused on the mental health of healthcare workers, research on post-traumatic stress disorder (PTSD) and its overall relationship to burnout, coping styles, resilience, and social support among nurses in emergency departments of tier 1 hospitals in Shanghai remains inadequate for this particular period of the winter H1N1 flu season. Most of the existing studies focus on the impact of ordinary periods or single factors on nurses’ mental health, and lack in-depth analysis of the combined effect of multiple factors, especially during specific periods of high incidence of influenza and sudden increase in work pressure. Based on the above background, this study aims to explore the following key questions: (1) What is the current status of PTSD among emergency department nurses in multiple tier 1 hospitals in Shanghai during the winter H1N1 influenza season? (2) What are the relationships between factors such as burnout, coping styles, mental resilience, and social support and PTSD among emergency department nurses? (3) How can targeted interventions be developed based on these relationships to improve the mental health of emergency department nurses and improve the quality of nursing services?

This research demonstrates that during the winter H1N1 flu season, the PTSD-positive screening rate among emergency department nurses in top tertiary hospitals reached an alarming 46.90% (68/145). Nurses frequently find themselves under duress and in extreme conditions as they tirelessly combat for their patients’ life and well-being, rendering them susceptible to stress and trauma (Kosydar-Bochenek et al., 2017). Emergency nursing staff often encounter distressing and traumatic events, such as accidents, violence, and death. Repeated exposure to such incidents can result in the manifestation of PTSD symptoms. A meta-analysis encompassing 30,878 research subjects revealed that the prevalence rates of PTSD, depression, anxiety, and overall psychological distress among emergency personnel were 11, 15, 15, and 27%, respectively (Petrie et al., 2018). A nationwide cross-sectional survey conducted in Germany discovered a significant decrease in happiness levels among nursing personnel, with PTSD and depression rates found to be higher compared to the general population (Eiche et al., 2019). The COVID-19 pandemic has brought attention to the psychological well-being of healthcare professionals, with frontline healthcare workers, including nursing staff, potentially experiencing severe and long-lasting psychological consequences. Research by Asadi Aghajari et al. suggests that one-third of emergency healthcare professionals are affected by PTSD, exhibiting significant correlations with depression and occupational stress (Asadi Aghajari et al., 2023). While the study aimed to assess PTSD symptoms among emergency department nurses during the peak of the winter H1N1 influenza season, it is important to acknowledge that several potentially influential confounding variables were not measured or controlled for in the study design. Although participants with “significant family events” were excluded, other important factors such as prior mental health history, financial stress, sleep disturbances, and shift type (e.g., night vs. day shifts) were not accounted for. These variables are known to significantly influence both psychological resilience and vulnerability to occupational stress. For example, nurses working extended or irregular night shifts may experience more severe disruptions to circadian rhythms, reduced recovery time, and increased psychological burden, all of which can elevate PTSD risk. The relatively high rate of reported PTSD symptoms in the study may therefore reflect not only the acute stress of working during a pandemic peak but also the cumulative effects of pre-existing stressors and individual risk factors that were not assessed. Future studies should aim to include a broader range of personal, occupational, and psychosocial variables to better isolate the impact of occupational exposure from other contributing factors. A more nuanced understanding of these confounders would improve the accuracy of PTSD prevalence estimates and inform more targeted interventions for at-risk healthcare workers.

The findings of this study reveal that individuals with a positive screening for PTSD exhibit significantly higher scores in all dimensions of the MBI compared to the PTSD-negative group. Furthermore, the positive coping scores in the SCSQ were lower in the PTSD-positive group, while the negative coping scores were higher. In addition, the CD-RISC scores in each dimension were significantly lower in the PTSD-positive group, as were the SSRS scores in each dimension. Burnout is characterized by emotional exhaustion, decreased sense of accomplishment, depersonalization, and indifference toward work, resulting from an enduring imbalance between work and rest. Clinical nursing, characterized by high intensity, technical complexity, and occupational hazards, ranks among the professions with the highest prevalence of burnout (Edú-Valsania et al., 2022). The demanding nature of the nursing profession, coupled with the challenging work environment, has led to persistently high rates of burnout among healthcare practitioners (Shanafelt et al., 2015; Shanafelt et al., 2022). Notably, Chirico et al. highlighted that burnout represents a more serious occupational health concern, with professionals in high workload occupations, such as teachers and healthcare providers, being particularly susceptible to burnout (Sullivan et al., 2022). The detrimental effects of burnout encompass chronic work-related stress, increased intent to leave the profession, and compromised quality of healthcare delivery and nursing care (Gualano et al., 2021). Previous research has demonstrated that burnout serves as a significant predictor for post-traumatic stress disorder symptoms among firefighters and police officers, with higher levels of burnout associated with more severe post-traumatic stress symptoms (Ogińska-Bulik and Juczyński, 2021; Jo et al., 2018).

Coping strategies play a crucial role in the prevention and management of PTSD. Positive coping strategies involve accepting reality, confronting stressors head-on, actively seeking solutions, and seeking support when needed. Conversely, negative coping strategies encompass distorting reality, avoiding self-reflection, and exhibiting self-destructive behaviors. Higher scores on negative coping strategies are associated with an increased vulnerability to post-traumatic stress reactions (Kucmin et al., 2018). The negative coping style of nurses was a more prominent predictor of PTSD than that of teachers, possibly related to the high-pressure environment in the emergency department (Zhang et al., 2019). In the aftermath of a traumatic event, it is advised that emergency department nurses who exhibit higher levels of negative coping strategies engage in open communication with colleagues, participate in community service activities, and employ humor or lightheartedness as a means to alleviate stress (Olff et al., 2025).

Psychological resilience refers to an individual’s capacity to effectively cope with and recover from adversity, as well as adapt to challenging circumstances (Sisto et al., 2019). Resilient individuals demonstrate flexibility in navigating various difficulties and challenges, and they possess the ability to adapt to uncertainty and change without succumbing to significant negative repercussions (Rakesh et al., 2019). According to the resource preservation theory, emergency nurses face resource depletion (such as work overload) during the flu season, while resilience (resource gain) reduces PTSD risk by buffering stress (Zhou et al., 2024). Psychological resilience serves as a pivotal factor in facilitating individuals’ recovery from stress and trauma, and it contributes to the prevention and mitigation of professional burnout among clinical nurses. Research has indicated that individuals with high levels of psychological resilience can ameliorate the adverse impact of prior traumatic experiences on the development and severity of PTSD symptoms (Cheng et al., 2023). Social support serves as a critical interpersonal resource that significantly influences the improvement of mental health outcomes following disasters (Calhoun et al., 2022). Insufficient social support exacerbates PTSD symptoms among nursing professionals who experience high levels of occupational stress (Hao et al., 2023). Unlike the burnout model from an evolutionary perspective (e.g., resource imbalance due to social class conflict), the direct protective effect of social support in this study is more significant, possibly due to the enhanced resource reserve of the medical team’s collaborative culture (Garcia, 2024). Chinese nurses rely more on colleagues to support stress relief, which is different from the predictive effect of family type (such as nuclear family) on PTSD in the Nepalese study, possibly reflecting the importance of teamwork in a collectivist culture (Parajuli et al., 2023).

In the context of frequent global public health incidents, the mental health of healthcare workers has attracted much attention. The findings of this study on a specific group of emergency department nurses during the winter H1N1 flu season not only enrich the content of mental health research of healthcare workers in specific departments during special periods in this field, but also provide reference for other similar studies, highlighting the importance and urgency of paying attention to the mental health of healthcare workers. In view of the higher incidence of PTSD among emergency department nurses in the winter H1N1 influenza season and related influencing factors in this study, it is necessary to strengthen the intervention measures for healthcare workers, which can improve the self-esteem of healthcare workers, promote psychological well-being and enhance stress coping skills. PTSD intervention for nurses can learn from postpartum trauma prevention strategies (such as expressive writing intervention), but group psychological training needs to be designed according to occupational characteristics (Dekel et al., 2024). In addition, programs that enhance psychological capital among teachers, such as resilience training, are equally applicable to nurses, but need to strengthen their coping skills in crisis situations (Du et al., 2022). The high comorbidity of PTSD (e.g., depression, anxiety) was also reflected in this study, suggesting the need for comprehensive intervention rather than single symptom management. As a complementary perspective, it is crucial to consider the psychological and occupational impacts faced by anesthesia professionals, particularly the prevalence of burnout syndrome. Recent literature has highlighted the significant emotional toll and chronic stress experienced by healthcare workers in high-stakes environments such as operating rooms. For instance, the study by Raudenská et al. (2020) explores the neurobiological underpinnings of burnout, emphasizing the role of chronic occupational stress in impairing clinical decision-making. Similarly, research published in the Revista Colombiana de Salud Ocupacional e Higiene Industrial (Nogueira Alves et al., 2023) analyzes burnout prevalence among healthcare providers in Latin America, suggesting systemic factors such as workload, support systems, and job control as key contributors. Most recently, a 2024 study in Frontiers in Psychology (Lin et al., 2024) further underscores the psychological vulnerability of healthcare professionals post-pandemic, linking emotional exhaustion with decreased patient care quality. Including these perspectives provides a more holistic understanding of the challenges faced in anesthetic practice and reinforces the need for institutional strategies to mitigate burnout and promote clinician well-being.

However, the limitations should be acknowledged. Sample selection limitation: The sample in this study only included emergency department nurses from top-tier hospitals during the winter influenza season, which may not represent nurses from other regions or different types of healthcare institutions. Therefore, the generalizability of the research findings may be limited. Recall bias: This study relied on self-reported questionnaires for data collection, which may be susceptible to recall bias. Nurses may have difficulty accurately recalling past events and experiences, which could affect their reporting of PTSD symptoms, burnout, psychological resilience, and other variables.

The incidence of PTSD among emergency department nurses during the winter influenza season is a pressing concern that necessitates careful consideration. It is closely intertwined with factors such as burnout, psychological resilience, coping strategies, and social support. Addressing this issue promptly is of paramount importance. In the flu season, the workload of emergency department nurses should be rationally allocated, including temporary nursing staff and flexible scheduling system, so as to reduce the degree of nurse burnout and reduce the risk of PTSD.