key: cord-1000482-yhmu42b2
authors: Carmassi, Claudia; Foghi, Claudia; Dell'Oste, Valerio; Cordone, Annalisa; Bertelloni, Carlo Antonio; Bui, Eric; Dell'Osso, Liliana
title: PTSD symptoms in Healthcare Workers facing the three Coronavirus outbreaks: what can we expect after the COVID-19 pandemic
date: 2020-07-20
journal: Psychiatry Res
DOI: 10.1016/j.psychres.2020.113312
sha: 5933773a0aa6e700dbcd7cfe23d1cb90fe8d278d
doc_id: 1000482
cord_uid: yhmu42b2

The COronaVIrus Disease-19 (COVID-19) pandemic has highlighted the critical need to focus on its impact on the mental health of Healthcare Workers (HCWs) involved in the response to this emergency. It has been consistently shown that a high proportion of HCWs is at greater risk for developing Posttraumatic Stress Disorder (PTSD) and Posttraumatic Stress Symptoms (PTSS). The present study systematic reviewed studies conducted in the context of the three major Coronavirus outbreaks of the last two decades to investigate risk and resilience factors for PTSD and PTSS in HCWs. Nineteen studies on the SARS 2003 outbreak, two on the MERS 2012 outbreak and three on the COVID-19 ongoing outbreak were included. Some variables were found to be of particular relevance as risk factors as well as resilience factors, including exposure level, working role, years of work experience, social and work support, job organization, quarantine, age, gender, marital status, and coping styles. It will be critical to account for these factors when planning effective intervention strategies, to enhance the resilience and reduce the risk of adverse mental health outcomes among HCWs facing the current COVID-19 pandemic.

The outbreak of Corona Virus Disease-19 (COVID) that emerged in December 2019 in Wuhan (China), quickly spread outside of China, leading the World Health Organization (WHO) Emergency Committee to declare a Public Health Emergency of International Concern (PHEIC) on January 30 th 2020 (Nishiura, 2020) , and a pandemic on March 11, 2020. The SARS-CoV2the virus responsible for COVID-19was isolated by 7 th January 2020, and belongs to the same viral family as the coronavirus syndrome (SARS-CoV) and the Middle East respiratory coronavirus syndrome (MERS-CoV). Both of these coronavirus-based respiratory syndromes infected over 10,000 cases in the past two decades, with overall mortality rates as high as 11% and 35%, respectively (Peeri et al.,2020; de Wit et al., 2016; Leung et al., 2004; WHO, 2004) . Compared to the Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS), the Corona Virus Disease-19 (COVID-19) has a greater transmission rate but a lower, though still significant, fatality rate (Peeri et al., 2020 . To date, with more than 3 million infected worldwide and a spread that is far from being contained, investigating the psychological impact of this pandemic on healthcare workers (HCWs) including physicians and nurses, has become increasingly important.

In the last two decades, first responders' mental health outcomes has been the focus of increasing attention, particularly in the aftermath of September 11 2001 terrorist attacks that shed light on the risks they are exposed to when operating in emergency settings, as they may be affected by physical and mental disorders, such as burnout and posttraumatic stress disorder (PTSD) (Perlman et al., 2011; Carmassi et al., 2016; Martin et al., 2017) . The DSM-5 (APA, 2013) indicates that "experiencing repeated or extreme exposure to aversive details of the traumatic event(s)" can be considered as potentially traumatic events (criterion A4: e.g. first responders collecting human remains, police officers repeatedly exposed to details of child abuse).

Healthcare Workers (HCWs) in emergency care settings are particularly at risk for PTSD because of the highly stressful work-related situations they are exposed to, that include: management of critical medical situations, caring for severely traumatized people, frequent witnessing of death and trauma, operating in crowded settings, interrupted circadian rhythms due to shift work) (Figley, 1995; Crabbe et al., 2004; Cieslak et al., 2014; Berger et al., 2012; Hegg-Deloye et al., 2013; Garbern et al., 2016) . PTSD rates have been reported to range from 10 to about 20% (Grevin, 1996; Clohessy and Ehlers, 1999; Robertson and Perry, 2010; DeLucia et al., 2019) , with even higher PTSD rates (8% to 30%) among Intensive Care Unit (ICU) staff, (Mealer et al., 2009; Karanikola et al., 2015; Machado et al., 2018) .

Although most individuals prove to be resilient after being exposed to a traumatic event (Bonanno et al., 2007) , several risk factors may compromise the effectiveness of adaptation, including prior psychiatric history, female sex, lack of social support (Brewin et al., 1999; Ozer et al. 2003; Carmassi et al., 2020) , having young children (Dell'Osso et al., 2013; Yehuda 2015 , Bryant 2019 ; experiencing feelings of helplessness during the trauma or intensity of emotions when exposed (i.e., anger, peritraumatic distress) (Vance et al., 2018) . On the other hand, resilience, defined as the capacity to react to stress in a healthy way through which goals are achieved at a minimal psychological and physical cost (Epstein and Krasner, 2013) , plays a key role in mitigating the impact of traumatic events and hence reducing PTSS, enhancing at the same time the quality of care (Wrenn, 2011; Ager et al., 2012; Haber et al., 2013; McGarry et al., 2013; Craun and Bourke, 2014; Hamid and Musa, 2017; Colville et al., 2017; Cleary et al., 2018; Winkel et la., 2019) . This interplay of risk and resilience factors becomes even more complex and challenging when applied in the context of an infectious epidemic. This statement is first supported by the fact that, as previous studies outlined, during epidemics a high percentage of HCWs, (up to 1 in 6 of those providing care to affected patients), develops significant stress symptoms (Lu et al., 2006; McAlonan et al., 2007) It is worth considering that in epidemic contexts HCWs are first in line facing the clinical challenges intrinsically linked to the course of the disease while under the constant personal threat of being infected or representing a source of infection.

The current COVID-19 pandemic is characterized by some relevant features that increase the risk for PTSD among HCWs addressing the emergency, such as the unprecedented numbers of critically ill patients, with an often unpredictable course of the disease, high mortality rates and lack of effective treatment, or treatment guidelines (Wang, 2020; Peeri et al, 2020) . Thus, the burden of the current outbreak on healthcare providers deserves the closest attention, as it is extremely likely that health care workers involved in the diagnosis, treatment and care of patients with COVID-19 are at risk of developing psychological distress and other mental health symptoms (Bao et al., 2020; Lai et al., 2020) The aim of the present paper is therefore to systematically review the studies investigating the potential risk and resilience factors for the development of PTSD symptoms in HCWs who faced the two major Coronavirus outbreaks that occurred worldwide in the last two decades, namely the SARS and the MERS, as well as the ongoing COVID-19 pandemic, in order to outline effective measures to reduce the HCWs' psychiatric burden during the current crisis affecting healthcare systems all over the world.

We reviewed articles indexed in the electronic database PubMed until 20 th April 2020. No time limit was set in regard to the year of publication. The search terms were combined with the Boolean operator as follows: "(Post-traumatic stress OR Post-traumatic stress disorder OR Post-traumatic stress symptoms OR PTSD OR PTSS) AND (Severe Acute Respiratory Syndrome OR SARS OR Middle East Respiratory Syndrome OR MERS OR Corona Virus Disease 19 OR COVID-19 OR Coronavirus)". Furthermore, relevant articles were extracted from the references section of the manuscripts found in the initial search, to complete our search.

We included articles that met the following inclusion criteria: original studies on humans investigating possible risk and/or resilience factors for PTSD symptoms in HCWs facing the coronavirus outbreaks of SARS, MERS and COVID-19. Articles in print or published ahead of print were accepted. The exclusion criteria were: (a) studies involving general population samples that did not consider a sub-sample of HCWs; (b) studies examining other mental health symptoms but not PTSS; (c) studies assessing PTSS but not considering potential risk and resilience factors;

(d) literature reviews; (e) full text not available; (f) not available in English.

The first author screened each study for eligibility by reading the title and abstract. Any uncertainties about eligibility were clarified through discussion among all authors. Decisions for inclusion or exclusion are summarized in a flow chart according to PRISMA recommendations, usually used to conduct meta-analyses and systematic reviews of randomized clinical trials, but that have also been used for other types of systematic reviews such as our present one (Moher et al., 2009 ).

The study selection process is outlined in a flow-chart (Figure 1) . The electronic database search returned 263 publications. Following a preliminary screening of the titles and abstracts, 47 articles were considered of potential relevance, their eligibility was assessed by means of a full text examination. Twenty-four of these studies, published between 2004 and 2020, were included in this review. The main reasons for study exclusion were: the absence of a HCW sample or sub-sample, the lack of data regarding PTSS and/or about possible risk or resilience factors related to psychopathology.

The key characteristics of the studies included are summarized in Table 1 . All retrieved studies were published between January 2004 and April 2020. Nineteen studies were on the SARS 2003 outbreak, two on the MERS 2012 outbreak, and three on the ongoing Covid-19 outbreak. Nine studies were on a mixed population in which HCWs represented a sub-sample (Bai et al., 2004; Chong et al., 2004; Kwek et a., 2006; Reynolds et al., 2007; Lancee et al., 2008; Wu et al., 2009; Mak et al., 2010; Wing and Leung, 2012; Li et al., 2020) while all other studies included HCWs only. Finally, five studies included specifically survivors from the infection (Kwek et al., 2006; Lee et al., 2007; Mak et al., 2010; Wing and Leung, 2012; Ho et al., 2005) .

Level of exposure. Ten studies Maunder et al., 2004; Lin et al., 2007; Su et al., 2007; Styra et al., 2008; Wu et al., 2009; Lee et al., 2018 , Lai et al, 2020 Jung et al, 2020 ) highlighted the role of exposure level, such as working in high-risk wards or in front-line settings during the Coronavirus outbreaks, as the major risk factor for developing PTSS and PTSD.

Particularly, they pointed out the relevance of perceived threat for health and life and the administrative staff, finding 2 to 3 times higher PTSS rates among respondents who worked in high-risk locations and perceived high SARS-related risks, beside an increased risk for subsequent alcohol abuse/dependence. This latter resulted significantly related with hyper-arousal symptoms. A further study in Toronto (Styra et al., 2008) confirmed the impact of operating in a high-risk unit, and first reported that caring for only one SARS patient was related to a higher risk than caring for multiple SARS patients. A recent study on 147 nurses who worked in MERS units during the outbreak found higher PTSD rates among emergency HCWs than among non-emergency ones (Jung et al., 2020) . To date, two studies have explored this issue in the COVID-19 pandemic. found among 526 nurses, that those who worked on the frontline appeared to be less prone to developing PTSS compared to second-line ones; conversely Kang et al. (2020) in a large study on 994 HCWs in Wuhan reported the exposure level to infected people, more broadly including colleagues, relatives or friends, to be a risk factor for mental health problems, including PTSS.

Occupational role. Five studies, four on the SARS epidemic and one on the COVID-19 pandemic, highlighted the occupational role as a major risk factor for PTSD or PTSS in Coronavirus outbreaks. Maunder et al. (2004) found on a sample of 1557 HCWs collected in Toronto, higher PTSS rates among nurses and explained this finding by means of the longer contact and higher exposure to patients of the nursing staff. A study on 96 emergency HCWs, assessed six months after the 2003 SARS outbreak, revealed a greater burden of PTSS among nurses than among physicians (Tham et al., 2004) . A further study by Phua et al. (2005) confirmed this finding in a sample of 99 HCWs. Finally, a most recent study on 1,257 hospital physicians and nurses caring for COVID-19 patients reached the same conclusion (Lai et al., 2020) .

Three studies on the SARS outbreak and one on the COVID-19 pandemic reported that younger HCWs had a greater risk of developing PTSS (Sim 2004; Su et al., 2007; Wu et al., 2009) . From a wider perspective, further studies pointed out an association between fewer years of work experience and an increased PTSS risk in HCWs, as described in two SARS studies Lancee et al., 2008) and in one COVID-19 study (Lai et al., 2020) . As far as gender is concerned, while one recent study on COVID-19 reported a higher risk for the female HCWs, a previous study involving 1,257 HCWs in a tertiary hospital affected by SARS found an increased risk of PTSS among males .

Three studies focused on the relevance of marital status, two of which referred to the SARS outbreaks and one to the current COVID-19 pandemic. Chan and Huak (2004) in a study on 661 HCWs in Singapore showed that those who were not married were more adversely affected than married ones. In contrast, a further study in Singapore (Sim et al., 2004) found a positive association between post-traumatic morbidities and being married. Likewise, a recent case control study on HCWs facing the COVID-19 pandemic showed that married, divorced or widowed operators reported higher scores in vicarious traumatization symptoms compared to unmarried HCWs .

Three SARS studies on Chinese hospital staff members (Bai et al., 2004; Reynolds et al., 2007; Wu et al., 2009 ) and one on the MERS outbreak (Lee et al., 2018) consistently reported high levels of PTSS among HCWs who had been quarantined. More specifically, Bai et al. (2004) examining 338 HCWs in an East Taiwan hospital found that 5% of them suffered from acute stress disorder, with quarantine being the most frequently associated factor, and a further 20% felt stigmatized and rejected in their neighborhood because of their hospital work, with also 9% reporting reluctance to work and/or considering quitting their job.

Similar findings emerged from a Canadian SARS study on 1,057 subjects (Reynolds et al. 2007) , in which quarantined HCWs reported more PTSS than non-HCWs quarantined individuals. Moreover, in a study on MERS outbreak, Lee et al. (2018) assessed PTSS experienced by 359 university HCWs who cared for infected patients, observing that quarantined HCWs had a higher risk of developing PTSS which persisted over time, particularly sleep and numbness-related symptoms.

More in general, social isolation and separation from family was found to be associated with higher rates of PTSS in SARS outbreak, as well as having friends or close relatives with the infection (Maunder et al., 2004; Chong et al., 2004; Wu et al, 2009 ).

Three studies on SARS have stressed the presence of previous psychiatric disorders as a risk factor for the development of PTSS (Sim 2004; Su et al., 2007; Lancee et al., 2008) . Accordingly, Su et al. (2007) on a sample of 70 nurses from two SARS units and 32 nurses from two non-SARS units found highlighted a previous history of mood disorders as a major risk factor for PTSS. One study on MERS outbreak confirmed this finding (Jung et al., 2020) .

Family and Social Support. Two studies on the SARS outbreak highlighted the support of family and friends as having a major role in protecting from PTSS development (Chan and Huak, 2004; Su et al., 2007) . In particular, Su et al. (2007) investigating 102 nurses found that strong social and family support protected against acute stress, with a positive impact on their global functioning as a function of time.

Supervisors and Colleagues Support. Three researches concerning the SARS outbreak (Chan and Huak, 2004; Maunder et al., 2006 , Lancee et al., 2008 and one on the MERS (Jung et al., 2020) , reported a protective role of the support from supervisors/colleagues. Particularly, Lancee et al (2008) , in 139 HCWs in Canada, showed feeling well supported while working as a resilience factor also in the long-term. Jung et al. (2020) noticed that management strategies based on supervisors' support proved helpful in order to reduce PTSS in 147 nurses in three isolation hospitals in South Korea during the MERS outbreak.

Training. The perception of being adequately trained was identified as a potentially protective factor in two studies on the SARS (Maunder et al., 2006; Lancee et al., 2008) . , Comparing 769

Canadian HCWs displaced in 9 hospitals that treated SARS patients and 4 hospitals that did not, from 13 to 26 months after the outbreak, Maunder et al. (2006) suggested the importance of supportive interventions in preventing PTSD and PTSS with particular impact on maladaptive coping styles.

Work organization. The same authors reported that working in structured units and the perceived safety of the working environment are further factors which seem to enhance the resilience of HCWs, in line with findings of another study by Su et al., 2007) . Moreover, it has also been observed that a clear communication of directives and precautionary measures to be adopted was related to a better outcome with regard to PTSS (Chan and Huak, 2004) .

In five studies on the SARS outbreak (Chan and Huak 2004; Sim et al., 2004; Phua et al., 2005; Su et al., 2007; Wu et al., 2009) , positive coping strategies were reported to be a protective factor against the development of PTSD psychopathology. Particularly, in a study carried out in Singapore on 41 physicians and 58 nurses, Phua et al. (2005) reported an association between the use of humor and planning as coping strategies, and lower rates of PTSD. Other protective coping styles included: the altruistic acceptance of work-related risks (Wu et al., 2009) , the ability to talk to someone about their experiences, and the presence of religious beliefs (Chan and Huak 2004) . Accordingly, Maunder et al. (2006) found that maladaptive coping strategies, such as avoidance, hostile confrontation and self-blame, resulted in worse outcomes in terms of PTSS and Sim et al (2004) reported that less venting, humor and acceptance were associated to higher levels of PTSS. Consistently, positive coping strategies, such as motivation to learning different skills, have been indicated as resilience factors also in HMWs dealing with the current COVID-19 pandemic .

Five studies focusing on HCWs who survived the SARS infection highlighted this population as particularly "at risk" for PTSD. Kwek et al. (2006) in a sample of SARS survivors at 3 months postdischarge found that HCWs were more affected by PTSS than non-HCWs. Lee et al. (2007) examined a sample of 96 Hong Kong SARS survivors divided into sub-samples of HCWs and non-HCWs, found that while PTSS levels were similar in the two sub-samples at the peak of the outbreak, HCWs compared to non-HCWs, reported significantly higher PTSS one year after discharge, suggesting a lack of recovery as a function of time, among HCW SARS survivors. In line with this, a later study among 233 Chinese SARS survivors also reported a higher risk of PTSD among HCW compared to non-HCW (Wing and Leung, 2012) . Furthermore, a study conducted on a sample of 90 Hong Kong SARS survivors at 30 months after the outbreak (Mak et al. 2010) showed that being a HCW was significantly associated with PTSD development, despite the authors hypothesizing that this finding could be gender-biased because the majority of the sample was made up of female HCWs. Finally, Ho et al. (2005) in 97 HCWs in Hong Kong found a positive correlation between the presence of pronounced SARS-related fears and PTSS burden, particularly intrusion symptoms; in addition HCWs who had recovered from SARS appeared to be more concerned about death, discrimination and quarantine than those who had not been infected.

To the best of our knowledge we conducted the first review addressing PTSD and PTSS risk and resilience factors in HCWs who were involved in the three major recent Coronavirus outbreaks, namely the SARS, the MERS and the current COVID-19, which have affected the worldwide population in the last two decades. Converging data suggest a high risk for PTSD development among emergency HCWs, with studies consistently outlining several risk factors that are enhanced in the case of these highly lethal outbreaks, such as: the frequent unpredictability of daily caseloads, The majority of studies included in our review focused on the 2003 SARS outbreak; fewer data were available on the MERS, and the studies on COVID-19 are only emerging at the time of writing. All these studies reported a high risk for adverse psychological reactions, particularly PTSS and PTSD among HCWs, suggesting the proximity to "ground zero" as a primary risk factor (Kwek et al., 2006; Lee et al., 2018) . HCWs' fear of contagion and infection of their family, friends and colleagues, feelings of uncertainty, stigmatization and rejection in their neighborhood because of their hospital work were also reported. Studies also reported the reluctance to work and/or considering quitting their job, as well as high levels of stress, anxiety and depression symptoms, which could have long-term psychological implications (Maunder et al., 2003; Bai et al., 2004; Lee et al., 2007; Wu et al., 2009 ). The self-perceived high risk for contagion might be the most important aspect related to the front-line activities, with for example Su et al. (2007) , failing to find any significant difference between HCWs in SARS vs. non-SARS units in PTSD prevalence rate .

This suggests that not only HCWs working within the SARS units, but also those working outside them and facing uncertainty because of the displacement, might develop PTSS during the outbreak.

In this regard, in the ongoing COVID-19 pandemic, the lack of personal protection devices represents a critical issue.

Interestingly, however, some authors found first-line exposure to have a protective effect. Styra et al. (2008) reported that HCWs working in SARS high risk units, as expected, experienced greater distress than HCWs displaced in other departments such as the psychiatric one, but contrary to expectations HCWs caring for many SARS patients while working in high-risk units emerged as being less distressed. This finding suggests that experience in treating SARS patients may be a mediating factor that could be amenable to intervention in future outbreaks. This is in line with more recent findings from a COVID-19 study, according to which PTSS severity of non-front-line nurses was greater than that of front-line nurses, who showed stronger psychological endurance.

The authors argue that this finding may be explained considering that front-line nurses were voluntarily selected and provided with sufficient psychological preparation. Moreover, the selected front-line nurses were mainly middle-level backbone staff with working experience and psychological capacity .

Hence, there is evidence that perceived adequacy of training represents a protective factor against adverse outcomes of traumatic exposure (Maunder et al., 2006; Lancee et al., 2008) . Similarly, other factors concerning positive working organization, such as working in structured units, a sense of protection of environment (Maunder et al., 2006; Su et al., 2007) and clear communication of directives and of precautionary measures (Chan and Huak, 2004) , have proven to be protective factors against the development of PTSS in HCWs. In particular, Chan and Huak (2004) The support from family and friends as well as that from supervisors and colleagues has been shown to represent an important resilience factor against the development of PTSS, as widely demonstrated in the literature (Chan and Huak, 2004; Maunder et al., 2006; Su et al., 2007; Lancee et al., 2008) . Nevertheless, this matter deserves further consideration since in this peculiar clinical setting the implications of the contagion risk often lead to self-isolation, with subsequent decreased social support. Some important individual risk and resilience factors for PTSS have also been reported among HCWs facing a coronavirus outbreak. First, female gender. Despite the fact that the majority of the studies corroborate the preventive role of professional training as to PTSD onset up to the point of flattening of the gender gap which is commonly observed in PTSD reports, most of the studies on HCWs dealing with Coronavirus outbreaks tend to show a higher incidence of PTSD among women. Females, in fact, were shown to be most affected by PTSS in three SARS studies Reynolds et al., 2007; Lai et al., 2020) , as well as younger HCWs or HCWs with fewer years of work experience (Reynolds et al., 2007; Lancee et al., 2008) . Moreover, nurses proved to be more affected by PTSS than other HCWs (Tham et al., 2004; Maunder et al., 2004) . Although this has been explained as related to closer contact with infected patients, we may also argue that often the nurse staff are mostly women. Further studies in this regard are thus warranted. Outbreaks threatening family members' well-being or affecting children's care, in fact, may constitute a burden for women (Carmassi et al., 2019) . It is worthy of note that all these factors could be influenced by coping styles adopted by the HCWs to address the psychic burden of the outbreak.

Some studies focused on positive coping styles that were associated to a better outcome (Phua et al., 2005; Wu et al., 2009 ). Among these, Phua et al. (2005) found that physicians chose humor as a coping strategy more frequently than nurses, and this resulted in lower post-traumatic stress morbidity. Other authors stressed the effect of maladaptive coping styles in predicting PTSS, such as avoidance, hostile confrontation and self-blame (Maunder et al., 2006) .

As previously highlighted, the sense of isolation was found to be an important factor related to PTSS. Consequently, HCWs who had been quarantined were shown to be at higher risk (Bai et al., 2004) as well as HCW survivors from the infection. These latter constitute a special population in which the impact of infectious disease, along with related fears for one's health and for the contagion of loved ones and the sense of isolation and the rejection due to the stigma, lead to a greater PTSS burden (Wing and Leung, 2012) .

More recently, scientists, clinicians and the general public, in fact, have been increasingly referring to the current COVID-19 emergency and its subsequent impact on health care systems, as the "9/11 of health care systems". First studies reported high levels of psychopathological burden in HCWs dealing with the COVID-19 pandemic in China, including depression, anxiety, insomnia and PTSS Kang et al., 2020; Lai et al., 2020) . In particular, anxiety and PTSS symptoms resulted higher in females, nurses and in HCWs with fewer years of work experience (Lai et al., 2020; Huang et al., 2020) . HCWs are called to confront this new scenario under widespread media coverage and in a context of a persisting imbalance between needs and resources, increasing the decisional burden and the feelings of hopelessness; they are also forced to deal with challenging expectations of the patients and their relatives in a framework characterized by unusual communicative constraints. Moreover, the fear of contagion is amplified by the lack of personal protective equipment (PPE) and the high number of infected or deceased colleagues, and is associated to the concern of representing a threat to family members: this often leads to selfisolation. As a consequence, loneliness, along with the risk of a growing trend towards social stigmatization of HCWs as potential carriers of infection (WHO, 2020) results in deprivation of social support, which is listed among the main factors of resilience.

Despite the slight decrease in the COVID-19 contagion rate, the impact on HCWs mental health may produce enduring effects. Finally, some evidence revealed a significant time-effect on reducing PTSD symptom ratings, as observed in a SARS study by Su et al. (2007) , reporting a 50% decrease after one month, no-one meeting the criteria for PTSD. Conversely, a MERS study by Lee et al. (2018) reported that HCWs performing one month before MERS-related tasks were at higher risk for symptoms of PTSD even after time had passed, and the risk was increased in sleep and numbness-related symptoms, in particular if home quarantine was implemented.

For all these reasons, providing a timely response to psychological pressure on HCWs in order to prevent negative mental health outcomes requires the development of specific intervention strategies (Dell'Osso et al., 2015) . Such strategies cannot but be based on a careful survey of both risk and resilience factors that may be playing a role in this special working population and should take into account what the studies conducted in the aftermath of the previous outbreaks reported.

When discussing our results some limitations should be considered. First, the lack of a quality assessment of the studies. Second, we consulted only one database for our search (PubMed). Third, most of the included articles (N=16) adopted the Impact of Event Scale scores, which is a wellknown rating scale that provides a subjective measure of perceived stress (Horowitz et al., 1979; Marziali and Pilkonis, 1986; Weiss et al., 1984) , to detect PTSD or PTSS. Fourth, surveys give us a limited glimpse into a complex psychological dynamic that happens with healthcare providers in isolation wards, because they rely on voluntary responses by the subjects, who may choose not to revisit a traumatic experience by participating in the survey, thus leading to under-reporting the incidence of traumatic sequelae . This is in line with Chen et al. (2020) who reported how the implementation of psychological intervention services in the COVID-19 pandemic proved to be problematic, because medical staff were reluctant to participate in the group or individual psychology interventions provided to them. Fifth, some studies reported that while quarantined HCWs consistently showed more frequent adverse psychological impacts than non-HCWs, their experience was probably influenced by their job-related experiences with SARS and not unique to their HCW status (Reynolds et al. 2007 ). Finally, no information was available on HCW family members, particularly on the possible impact of the presence of children as a possible PTSS risk factor (Dell'Osso et al., 2013) .

We have examined studies carried out in the context of the three Coronavirus outbreaks in order to outline PTSD and PTSS risk and resilience factors impacting on HCWs and to consistently enhance the effectiveness of intervention strategies. While the COVID-19 pandemic is straining healthcare systems all over the world, awareness of the impact of the emergency on the HCWs' mental health is rising, consistently with evidence of the high risk of them developing psychological distress, such as PTSD and PTSS, under similar circumstances. To date, despite some recommendations released by international organizations (WHO, 2020; IASC, 2020; IFRC, 2020) and a variety of action proposals, a systematic approach is not yet in place. Efficacious treatments for PTSD and PTSS exist (Lee and Bowles, 2020; Charney et al., 2018) , and healthcare systems should also focus on prepare to roll out these treatments among HCWs should prevention strategies fail to prevent the development of these conditions.

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

No conflict of interest. No disclosures to declare of any relationship with a commercial company that has a direct financial interest in subject matter or materials discussed in article or with a company making a competing product.

Not applicable. 

Stress, mental health, and burnout in national humanitarian aid workers in Gulu, Northern Uganda

Diagnostic and Statistical Manual of Mental Disorders, DSM-5

Survey of stress reactions among health care workers involved with the SARS outbreak

2019-nCoV epidemic: address mental health care to empower society

Rescuers at risk: a systematic review and meta-regression analysis of the worldwide current prevalence and correlates of PTSD in rescue workers

What predicts psychological resilience after disaster? The role of demographics, resources, and life stress

Acute stress disorder and posttraumatic stress disorder in victims of violent crime

Traumatic stress within disaster-exposed occupations: overview of the literature and suggestions for the management of traumatic stress in the workplace

Post-traumatic stress disorder: a state-of-the-art review of evidence and challenges. World Psychiatry

DSM-5 PTSD and posttraumatic stress spectrum in Italian emergency personnel: correlations with work and social adjustment

Post-traumatic stress and major depressive disorder in parent caregivers of children with a chronic disorder

PTSD in the aftermath of a natural disaster: What we learned from the Pisa-L'Aquila Collaboration Project

Psychological impact of the 2003 severe acute respiratory syndrome outbreak on health care workers in a medium size regional general hospital in Singapore

Evidenced-Based Treatment of Posttraumatic Stress Disorder: An Updated Review of Validated Psychotherapeutic and Pharmacological Approaches. Harvard review of psychiatry

Psychological impact of severe acute respiratory syndrome on health workers in a tertiary hospital

A meta-analysis of the relationship between job bournout and secondary traumatic stress among workers with indirect exposure to trauma

The effectiveness of interventions to improve resilience among health professionals: a systematic review

PTSD symptoms, response to intrusive memories and coping in ambulance service workers

Coping with staff burnout and work-related posttraumatic stress in intensive care

Are health professionals getting caught crossfire? The personal implications of caring for trauma victims

The use of humor to cope with secondary traumatic stress

Symptoms of Post-traumatic Stress Disorder among pediatric acute care nurses

SARS and MERS: recent insights into emerging coronaviruses

Age, gender and epicenter proximity effects on post-traumatic stress symptoms in L'Aquila 2009 earthquake survivors

Bridging the gap between education and appropriate use of benzodiazepines in psychiatric clinical practice

Prevalence of Post-Traumatic Stress Disorder in emergency physicians in the United States

Physician resilience: what it means, why it matters, and how to promote it

Compassion Fatigue: Coping with secondary traumatic stress disorder in those who treat the traumatized

Trauma exposure, posttraumatic stress disorder and the effect of explanatory variables in paramedic trainees

A systematic review of health outcomes among disaster and humanitarian responders

Posttraumatic stress disorder, ego defense mechanisms, and empathy among urban paramedics

Predictors of professional quality of life among physicians in a conflict setting: the role of risk and protective factors

The mediating effects of coping strategies on the relationship between secondary traumatic stress and burnout in professional caregivers in the UAE

Current state of knowledge of post-traumatic stress, sleeping problems, obesity and cardiovascular disease in paramedics

Fear of severe acute respiratory syndrome (SARS) among health care workers

Impact of Event Scale: A Measure of Subjective Stress

Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi

Briefing note on addressing mental health and psychosocial aspects of COVID-19

support-emergency-settings/interim-briefing International Federation of Red Cross and Red Crescent Societies (IFRC), 2020. Mental health and psychosocial support for staff, volunteers and communities in anoutbreakof novel Coronavirus

Post-traumatic stress disorder among paramedic and hospital emergency personnel in south-east

The crossroads of posttraumatic stress disorder and physician burnout: a national review of United States trauma and nontrauma surgeons

Unveiling posttraumatic stress disorder in trauma surgeons: a national survey

Assessing the Presence of Post-Traumatic Stress and Turnover Intention Among Nurses Post-Middle East Respiratory Syndrome Outbreak: The Importance of Supervisor Support

Impact on mental health and perceptions of psychological care among medical and nursing staff in Wuhan during the 2019 novel coronavirus disease outbreak: A cross-sectional study

Dysfunctional psychological responses among Intensive Care Unit nurses: asystematic review of the literature

Quality of life and psychological status in survivors of severe acute respiratory syndrome at 3 months postdischarge

Factors Associated With Mental Health Outcomes Among Health Care Workers Exposed to Coronavirus Disease

Prevalence of Psychiatric Disorders Among Toronto Hospital Workers One to Two Years After the SARS Outbreak

Stress and psychological distress among SARS survivors 1 year after the outbreak

Psychological impact of the 2015 MERS outbreak on hospital workers and quarantined hemodialysis patients

Navigating treatment recommendations for PTSD: A rapid review

The epidemiology of severe acute respiratory syndrome in the 2003 Hong Kong epidemic: an analysis of all 1755 patients

Vicarious traumatization in the general public, members, and non-members of medical teams aiding in COVID-19 control

The psychological effect of severe acute respiratory syndrome on emergency department staff

The mental health of hospital workers dealing with severe acute respiratory syndrome

Alcohol use and suicidality in firefighters: Associations with depressive symptoms and posttraumatic stress

The measurement of subjective response to stressful life events

The immediate psychological and occupational impact of the 2003 SARS outbreak in a teaching hospital

Factors associated with the psychological impact of severe acute respiratory syndrome on nurses and other hospital workers in Toronto

Long-term psychological and occupational effects of providing hospital healthcare during SARS outbreak

Immediate and sustained psychological impact of an emerging infectious disease outbreak on health care workers

Paediatric health-care professionals: relationships between psychological distress, resilience and coping skills

The prevalence and impact of post traumatic stress disorder and burnout syndrome in nurses

Symptoms of post-traumatic stress disorder among emergency medicine residents

The PRISMA Group Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement

The extent of transmission of novel coronavirus in Wuhan

Predictors of posttraumatic stress disorder and symptoms in adults: a meta-analysis

Trauma and stress-related disorders in German emergency physicians: the predictive role of personality factors

The SARS, MERS and novel coronavirus (COVID-19) epidemics, the newest and biggest global health threats: what lessons have we learned?

Short-term and medium-term health effects of 9/11

Prevalence of PTSD and common mental disorders amongst ambulance personnel: a systematic review and meta-analysis

Coping responses of emergency physicians and nurses to the 2003 severe acute respiratory syndrome outbreak

Understanding, compliance and psychological impact of the SARS quarantine experience

Institutionally based health care workers' exposure to traumatogenic events:systematic review of PTSD presentation

Secondary traumatic stress in emergency medicine clinicians

Severe acute respiratory syndrome-related psychiatric and posttraumatic morbidities and coping responses in medical staff within a primary health care setting in Singapore

The impact of occupational hazards and traumatic events among Belgian emergency physicians

Impact on health care workers employed in high-risk areas during the Toronto SARS outbreak

Prevalence of psychiatric morbidity and psychological adaptation of the nurses in a structured SARS caring unit during outbreak: a prospective and periodic assessment study in Taiwan

Psychological morbidity among emergency department doctors and nurses after the SARS outbreak

Peritraumatic distress: A review and synthesis of 15 years of research

A novel coronavirus outbreak of global health concern

The Stress Response Rating Scale: a clinician's measure for rating the response to serious life-events

Summary of probable SARS cases with onset of illness from 1

World Health Organization. 2020. Mental health and psychosocial considerations during the COVID-19 outbreak

Mental health impact of severe acute respiratory syndrome: a prospective study

Physician resilience: a grounded theory study of obstetrics and gynaecology residents

Dr. Glenda L. Wrenn, The effect of resilience on posttraumatic stress disorder in trauma-exposed innercity primary care patients

The psychological impact of the SARS epidemic on hospital employees in China: exposure, risk perception, and altruistic acceptance of risk

Post-traumatic stress disorder

Workplace violence and self-reported psychological health: coping with post-traumatic stress, mental distress, and burnout among physicians working in the emergency departments compared to other specialties in Pakistan