The purpose of this study was to investigate the psychological impact of COVID-19 on EFO nurses in Chinese hospitals. We explored the effects of socio-psychological variables and working conditions on anxiety, stress and stress coping tendency, as well as the correlation of anxiety, stress, and stress coping tendency in EFO nurses.
Anxiety, stress and stress coping style of EFO nurses
Stress and anxiety are common mental health problems among nurses. The results of this study showed an anxiety score of 49.01± 5.46, which was slightly higher than those reported by Yu  and Yang . We found that 32.23% of EFO nurses had perceived stress in the present study, and previous studies also revealed that being a nurse was highly stressful [12, 15], especially for nurses working in emergency departments . During the outbreak of COVID-19 in China, EFO nurses served as gatekeepers of the medical system. Unlike nurses in other departments, EFO nurses have a higher risk of exposure to COVID-19. In addition, factors such as excessive workload, fear of family member infection, and the death of medical staff can also lead to stress and anxiety [12, 40, 41]. Coping is the cognitive and behavioral measure taken by individuals to life events and their own unbalanced state. In this study, the score of positive coping of EFO nurses was 1.97±0.57, which was higher than the Chinese norm (1.78±0.52).While the score of negative coping was 1.13±0.48, which was lower than Chinese norm (1.59±0.66) . Among the participants, 229(50.55%) were more likely to respond positively to stress, while 224(49.45%) were more likely to respond negatively，which was similar to the previous study in China . Nearly half of EFO nurses responded to stress mainly in a negative way, suggesting that appropriate interventions should be given to improve their coping style.
Predictors of stress, anxiety, and stress coping tendency
The models we used included gender, fear of infecting family members, regretting being a nurse, having children, confidence in fighting outbreak, rest time, professional attitudes, having attended infection prevention training, and number of night shifts; and they were all predictors of the mental health of EFO nurses.
Socio-psychological variables and working conditions as predictors, accounted for 19.2% of the variance in anxiety, 13.7% in stress domain, and 13.2% in stress coping tendency. Among variables, fear of infecting family members was the most influential and predictive of all three criterions. During infectious disease epidemic it was difficult for hospital workers to return home from the hospital because they worried about family infection [12, 40, 41]. Nurses are vulnerable to infection during outbreaks of infectious disease [40, 43-45], especially when there are emerging infectious diseases with infectious nature not entirely clear. During the COVID-19 outbreak, emergency and fever clinics in Chinese hospitals are the high-risk workplaces, where nurses are more likely to be exposed. COVID-19 is highly infectious, which make nurses even more worried about their family members, subsequently making them more anxious, stressed and more inclined to adopt negative coping methods.
Those who regretted becoming a nurse reported higher levels of anxiety, stress and mainly adopted negative coping style. Nurses who reported serving voluntarily were less stressed than those who were appointed . Some studies also suggested that the potential turnover rate for nurses may be high during an outbreak and that they may face more psychological problems [47, 48]. Wong et al found that 76.9% community nurses were unwilling to work because of psychological stress and fear of being infected by H1N1 influenza, and those who reported unwillingness were more depressed and were more stressful . It is unclear why respondents regretted becoming a nurse during the COVID-19 pandemic. We can only assume to the following reasons: protective working conditions or facilities may be unavailable , fears of infection, excessive workload, childcare responsibilities and prioritization of family members .
We also noted that 72.41% (328) respondents had attended infection prevention training, which resulted in lower levels of stress and adoption of positive coping style. Inadequate training in infection control, lack of knowledge and unclear specific tasks increased perceived personal risk and reduced willingness to work . Not only nurses, but also all those involved need to be trained for the skills necessary to protect them from infection . Institutional preparedness is a positive predictor of individual perceptions of preventive measures . Protection training can help to understand the nature of infectious diseases, standardize protection measures, enhance confidence, and improve nurses' compliance with infection control measures, thus reducing the risk of disease transmission. Protection training is necessary, especially for the highly infectious COVID-19. Medical institutions should attach great importance to improving the protection training system, and online and offline comprehensive training should be used to improve the occupational protection ability of EFO nurses.
Those who took fewer breaks and more night shifts each week had higher levels of anxiety and stress. The length of rest time and the number of night shifts can reflect whether the nursing resources are sufficient or not and the workload. Previous studies have suggested that long hours and high workloads are predictors of stress [12, 13, 40, 51]. Nurses' duties may change in response to the outbreak, which can also lead to stress and anxiety. Overworking can make the EFO nurse lose the sense of control to the life, produce the feeling of powerless, and even cause insomnia, headache, loss of appetite and other physical problems .Therefore, hospitals should ensure that the emergency and the fever clinics are adequately staffed with nurses, and the head nurse should arrange the shift of nurses in a coordinated way to ensure that they can get sufficient rest.
There were 35.98% (163) of the respondents had children and had higher levels of anxiety, similar to the results of Maunder and Leslie , but unlike Chen's study ，who found that nurses with more than two children reported the lowest levels of job stress, while nurses without children reported the highest levels of job stress and were more likely than other nurses to have destructive stress coping strategies. The opposite finding may be due to the timing of the survey. During infectious disease outbreaks, nurses have a duty to protect their own children from being infected，and the burden of caring for children grows as schools are closed. The double burden of family and work makes them more anxious.
Women made up the majority (96.47%) of our respondents and had higher levels of anxiety. Previous studies have shown that gender had different effects on mental health. During Ebola outbreak, male health workers experienced more mental distress . This is different from the results of this study, which may be due to the fact that the emergency and fever outpatient have undertaken most diagnosis and treatment in this COVID-19 epidemic, and the workload is large. Compared with women, men can better cope with the high workload. However, only 16 nurses in this study were male, so the findings should be applied only in the appropriate context and further research is needed.
Confidence in fighting the outbreak was negatively correlated with anxiety levels among EFO nurses. Confidence is a display of perseverance and optimism, which can reduce the degree of individual stress response and avoid psychological disorder. Confident nurses tend to have more abundant clinical professional knowledge and abilities, and can effectively manage their time and tasks . Confidence can help to stimulate professional potential, overcome pressure and difficulties, and maintain a good physical and mental state. In addition, Professional attitude is a positive predictor of stress coping tendency. The more positive the professional attitude, the more likely EFO nurses were to adopt positive coping tendency. Lam et al. found that during the influenza outbreak, nurses endured a considerable amount of hardship. They overcame their own risk of infection and provided nursing service largely because of professional loyalty, mission and obligation to perform professional duties ．A strong professional attitude contributes to the quality of care . Therefore, it is recommended that medical institutions should summarize the epidemic prevention and control work on a daily basis, and encourage nurses to share their clinical experience and feelings, affirm their professional value, and improve their professional identity and confidence in fighting the epidemic.
Correlation among stress, anxiety, and stress coping tendency
While controlling for socio-psychological and working condition variables, we found that stress was positively correlated with anxiety score, which is consistent with previous findings [57, 58]. It has been shown that constant high work stress may have negative physical and psychological effects on health (anxiety, depression, and burnout) .Coping tendency score was negatively correlated with anxiety and stress score, which is also consistent to those of previous studies [58, 60]. However, mental health is the result of multiple factors, so the relationship between variables and whether there is mediating effect is worthy of further discussion.