Table 1.

Author	Location	Participant Profile	Design	Measurement	Main Result
Sun et al. 2020	Both Wuhan and outside of Wuhan, China	Seventy-four (16.7%) male and 368 (83.3%) female individuals participated in this study. A total of 53 doctors, 348 nurses, 18 administrative and logistics staff and 23 other types of health workers participated in this study. In all, 337 subjects lived with their families, 27 subjects lived in dormitories and 38 subjects lived alone	Cross-sectional	Impact of Event Scale (IES) and a nine-question questionnaire	After the outbreak of 2019-nCoV, 395 (89.4%) of the 442 subjects thought that medical work was very risky. There were 381(86.2%) health workers who think they have more work pressure than before. The average score of high arousal dimension was 5.15 (S.D. = 4.71), and the median score was 4.0 (IQR 2.0, 7.0). The high arousal score of health workers in males was higher than that in females. The quarantined health workers have a higher score for high arousal.
Zhang et al. 2020	Online survey in China	A total of 2,182 Chinese subjects participated.	Cross-sectional	Insomnia Severity Index (ISI), the Symptom Check List-revised (SCL-90-R), and the Patient Health Questionnaire-4 (PHQ-4), which included a 2-item anxiety scale and a 2-item depression scale (PHQ-2).	Compared with nonmedical health workers (n = 1,255), medical health workers (n = 927) had a higher prevalence of insomnia (38.4 vs. 30.5%, p < 0.01), anxiety (13.0 vs. 8.5%, p < 0.01), depression (12.2 vs. 9.5%; p < 0.04), somatization (1.6 vs. 0.4%; p < 0.01), and obsessive-compulsive symptoms (5.3 vs. 2.2%; p < 0.01). They also had higher total scores of ISI, GAD-2, PHQ-2, and SCL-90-R obsessive-compulsive symptoms (p ≤ 0.01)
Song et al. 2020	Both Wuhan and outside of Wuhan, China	A total of 14,825 emergency department medical staff from 31 provinces in mainland China were surveyed.	Cross-sectional	The social support of participants was measured by the Perceived Social Support Scale (PSSS). The Center for Epidemiologic Studies Depression Scale (CES-D) was used to assess depressive symptoms. PTSD was assessed by the PTSD Checklist for DSM-5 (PCL-5)	The prevalence rates of depressive symptoms and post-traumatic stress disorder (PTSD) were 25.2% and 9.1%, respectively. Men were more likely to have depressive symptoms and PTSD than women. Those who were middle aged, worked for fewer years, had longer daily work time, and had lower levels of social support were at a higher risk of developing depressive symptoms and PTSD. Working in the Hubei province was associated with a higher risk of depressive symptoms, while those working in the Hubei province but residing in another province had a lower risk of depressive symptoms and PTSD. Being a nurse was associated with a higher risk of PTSD.
Mo et al. 2020	Wuhan, China	180 nurses from Guangxi who are involved in fighting against COVID-19 in Wuhan, those who have entered the clinical front line to participate in the rescue work and those who volunteered to participate in this study.	Cross-sectional	Data collection tools, including the Chinese version of the Stress Overload Scale (SOS) and the Self-rating Anxiety Scale (SAS), were used.	The SOS (39.91 ± 12.92) and SAS (32.19 ± 7.56) scores of this nurse group were positively correlated (r = 0.676, p < .05). Multiple regression analysis showed that only children, working hours per week and anxiety were the main factors affecting nurse stress (p = .000, .048, .000, respectively).
Lai et al. 2020	Both Wuhan and outside of Wuhan, China, but more hospitals in Wuhan were selected	1257 health care workers in 34 hospitals from January 29, 2020, to February 3, 2020, in China. Health care workers in hospitals equipped with fever clinics or wards for patients with COVID-19 were eligible.	Cross-sectional	The degree of symptoms of depression, anxiety, insomnia, and distress was assessed by the Chinese versions of the 9-item Patient Health Questionnaire, the 7-item Generalized Anxiety Disorder scale, the 7-item Insomnia Severity Index, and the 22-item Impact of Event Scale–Revised, respectively.	A considerable proportion of participants reported symptoms of depression, anxiety, insomnia, and distress. Nurses, women, frontline health care workers, and those working in Wuhan, China, reported more severe degrees of all measurements of mental health symptoms than other health care workers.
Zhu et al. 2020	Gansu Province, China	A total of 79 doctors and 86 nurses participated in the survey.	Cross-sectional	A cross-sectional survey was conducted in Gansu (China), with a questionnaire packet which consisted of the self-rating anxiety scale (SAS), self-rating depression scale (SDS), and the simplified coping style questionnaire (SCSQ).	The prevalence rates of anxiety and depression symptoms among doctors was 11.4% and 45.6%, respectively. The prevalence rate of anxiety and depression symptoms among nurses was 27.9% and 43.0%, respectively.
Du et al. 2020	Wuhan, China	Participants were frontline HCWs from two Wuhan-based hospitals (n = 200) and HCWs in the outreach team (n = 110) deployed to Wuhan from two outside hospitals.	Cross-sectional	Perceived stress via Perceived Stress Scale (PSS), depression via Beck Depression Inventory- II (BDI-II), and anxiety via Beck Anxiety Inventory (BAI).	the prevalence of elevated depressive (BDI-II scores ≥ 14) and anxiety symptoms (BAI scores ≥ 8): 12.7% and 20.1% of HCWs had at least mild depressive and anxiety symptoms, respectively. More than half (59.0%) had moderate to severe levels of perceived stress (PSS scores ≥ 14).
Qi et al. 2020	Hubei Province, China	A total of 1306 subjects (801 Frontline medical workers and 505 non-frontline medical workers) were enrolled from multiple hospitals in Hubei Province, China	Cross-sectional	An online questionnaire, including Pittsburgh Sleep Quality Index (PSQI), Athens Insomnia Scale (AIS) and Visual Analogue Scale (VAS), was used to evaluate sleep disturbances and mental status. Sleep disturbances were defined as PSQI>6 points or/and AIS>6 points. We compared the scores of PSQI, AIS, anxiety and depression VAS, as well as prevalence of sleep disturbances between FMW and non-FMW.	Compared to non-FMW, FMW had significantly higher scores of PSQI (9.3 ± 3.8 vs 7.5 ± 3.7; P < 0.001), AIS (6.9 ± 4.3 vs 5.3 ± 3.8; P < 0.001), anxiety (4.9 ± 2.7 vs 4.3 ± 2.6; P < 0.001) and depression (4.1 ± 2.5 vs 3.6 ± 2.4; P ¼ 0.001), as well as higher prevalence of sleep disturbances according to PSQI > 6 points (78.4% vs 61.0%; relative risk [RR] ¼ 1.29; P < 0.001) and AIS > 6 points (51.7% vs 35.6%; RR ¼ 1.45; P < 0.001).
Liu et al. 2020	Both Wuhan and outside of Wuhan, China	512 participating healthcare staff included doctors, nurses and administrative workers at hospitals equipped with a fever clinic or a COVID-19 ward in different regions in China. Administrative staff work in administration and did not directly engage in the treatment or care of infected patients.	Cross-sectional	Zung Self-rating Anxiety Scale (SAS) to assess anxiety, with the criteria of normal (⩽49), mild (50–59), moderate (60–70) and severe anxiety (⩾70).	The prevalence of anxiety was 12.5%, with 53 workers suffering from mild (10.35%), seven workers suffering from moderate (1.36%) and four workers suffering from severe anxiety (0.78%). After adjusting for sociodemographic characteristics (gender, age, education and marital status), medical staff who had had direct contact treating infected patients experienced higher anxiety scores than those who had not had direct contact (β value = 2.33, confidence interval (CI) 0.65–4.00; P = 0.0068). A similar trend was observed in medical staff from Hubei province, compared with those from other parts of China (β value = 3.67, CI 1.44–5.89; P = 0.0013).
Kang et al. 2020	Wuhan, China	994 medical and nursing staff	Cross-sectional	Patient health questionnaire-9, Generalized Anxiety Disorder, Insomnia Severity Index and the Impact of Event Scale-Revised	36.9 % had subthreshold mental health disturbances, 34.4 % had mild disturbances, 22.4 % had moderate disturbances, and 6.2 % had severe disturbances
Xiao et al. 2020	Wuhan, China	180 medical and nursing staff	Cross-sectional	Self-Rating Anxiety Scale, the General Self-Efficacy Scale, the Stanford Acute Stress Reaction Questionnaire, the Pittsburgh Sleep Quality	Levels of social support were significantly associated with self-efficacy and sleep quality and negatively associated with the degree of anxiety and stress
Liang et al. 2020	Guangdong Province, China	59 medical and nursing staff	Cross-sectional	Zung’s self-rating depression scale (SDS), Zung’s self-rating anxiety scale (SAS)	Several staff were experiencing clinically significant depressive symptoms

Footnote: We used the following search strateg in Pubmed (Medline) and EMBASE: Mental Disorders (“mental illness” OR “mental health” OR “mental disorder” OR “depression” OR “anxiety” OR “affective disorder” OR “psychological well-being” OR “psychological” OR “psychological distress” OR “stress” OR “post-traumatic stress disorder” OR “ptsd” OR “stress disorder” OR “mental disorders”[MeSH Terms] OR “Anxiety Disorders”[Mesh] OR “Stress Disorders, Traumatic”[Mesh] OR “Mood Disorders”[Mesh] OR “Depressive Disorder”[Mesh] OR “Stress, Psychological”[Mesh] OR “Psychological Distress”[Mesh]) AND COVID-19 (“COVID-19” OR “sars cov” OR “nCOV” OR “coronavirus 2” OR “novel coronavirus” OR “Severe Acute Respiratory Syndrome”[Mesh] OR “SARS” OR “severe acute respiratory syndrome coronavirus 2” OR “COVID-19” [Supplementary Concept]) AND Community Health Worker (“Community Health Worker” OR “Frontline Health Worker” OR “health care worker” OR “personnel” OR “clinician” OR “nurse” OR “midwife” OR “midwives” OR “first responder” OR “Community Health Workers”[Mesh] OR “Health Personnel”[Mesh]). The search was conducted on July 1^st, 2020, and yielded 496 entries after removal of duplicates and studies published before 2020 (as this could not have reported on COVID-19). In total, 12 studies reported on the mental health impacts among frontline health workers in LMICs, all coming from China.