Seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection among Veterans Affairs healthcare system employees suggests higher risk of infection when exposed to SARS-CoV-2 outside the work environment.

OBJECTIVE: The seroprevalence of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) IgG antibody was evaluated among employees of a Veterans Affairs healthcare system to assess potential risk factors for transmission and infection. METHODS: All employees were invited to participate in a questionnaire and serological survey to detect antibodies to SARS-CoV-2 as part of a facility-wide quality improvement and infection prevention initiative regardless of clinical or nonclinical duties. The initiative was conducted from June 8 to July 8, 2020. RESULTS: Of the 2,900 employees, 51% participated in the study, revealing a positive SARS-CoV-2 seroprevalence of 4.9% (72 of 1,476; 95% CI, 3.8%-6.1%). There were no statistically significant differences in the presence of antibody based on gender, age, frontline worker status, job title, performance of aerosol-generating procedures, or exposure to known patients with coronavirus infectious disease 2019 (COVID-19) within the hospital. Employees who reported exposure to a known COVID-19 case outside work had a significantly higher seroprevalence at 14.8% (23 of 155) compared to those who did not 3.7% (48 of 1,296; OR, 4.53; 95% CI, 2.67-7.68; P < .0001). Notably, 29% of seropositive employees reported no history of symptoms for SARS-CoV-2 infection. CONCLUSIONS: The seroprevalence of SARS-CoV-2 among employees was not significantly different among those who provided direct patient care and those who did not, suggesting that facility-wide infection control measures were effective. Employees who reported direct personal contact with COVID-19-positive persons outside work were more likely to have SARS-CoV-2 antibodies. Employee exposure to SARS-CoV-2 outside work may introduce infection into hospitals.

Professional practice for COVID-19 risk reduction among health care workers: A cross-sectional study with matched case-control comparison.

BACKGROUND: Health care workers (HCWs) are particularly exposed to COVID-19 and therefore it is important to study preventive measures in this population. AIM: To investigate socio-demographic factors and professional practice associated with the risk of COVID-19 among HCWs in health establishments in Normandy, France. METHODS: A cross-sectional and 3 case-control studies using bootstrap methods were conducted in order to explore the possible risk factors that lead to SARS-CoV2 transmission within HCWs. Case-control studies focused on risk factors associated with (a) care of COVID-19 patients, (b) care of non COVID-19 patients and (c) contacts between colleagues. PARTICIPANTS: 2,058 respondents, respectively 1,363 (66.2%) and 695 (33.8%) in medical and medico-social establishments, including HCW with and without contact with patients. RESULTS: 301 participants (14.6%) reported having been infected by SARS-CoV2. When caring for COVID-19 patients, HCWs who declared wearing respirators, either for all patient care (ORa 0.39; 95% CI: 0.29-0.51) or only when exposed to aerosol-generating procedures (ORa 0.56; 95% CI: 0.43-0.70), had a lower risk of infection compared with HCWs who declared wearing mainly surgical masks. During care of non COVID-19 patients, wearing mainly a respirator was associated with a higher risk of infection (ORa 1.84; 95% CI: 1.06-3.37). An increased risk was also found for HCWs who changed uniform in workplace changing rooms (ORa 1.93; 95% CI: 1.63-2.29). CONCLUSION: Correct use of PPE adapted to the situation and risk level is essential in protecting HCWs against infection.

COVID-19 in Malaysia: exposure assessment and prevention practices among healthcare workers at a teaching hospital.

INTRODUCTION: During the second wave of the coronavirus disease 19 (COVID-19) pandemic, Malaysia reported several COVID-19 clusters related to healthcare workers. Thus, addressing and understanding the risk of exposure in healthcare workers is important to prevent future infection and reduce secondary COVID-19 transmission within the healthcare settings. In this study, we aim to assess exposure and prevention practices against COVID-19 among healthcare workers at the Hospital Canselor Tuanku Muhriz, a university teaching hospital based in Kuala Lumpur, Malaysia. METHODOLOGY: A total of 571 healthcare workers at COVID-19 and non-COVID-19 wards as well as the emergency department and laboratory staff at COVID-19 testing labs were recruited. The presence of novel human coronavirus (SARS-CoV-2) and IgM/IgG antibodies were confirmed in all healthcare workers. The healthcare workers responded to an online Google Forms questionnaire that evaluates demographic information and comorbidities, exposure and adherence to infection prevention and control measures against COVID-19. Descriptive analysis was performed using Statistical Package for the Social Sciences 24.0. RESULTS: Three healthcare workers (0.5%) tested positive for SARS-CoV-2, while the remaining 568 (99.5%) were negative. All were negative for IgM and IgG antibodies during recruitment (day 1) and follow-up (day 15). More than 90% of the healthcare workers followed infection prevention and control practices recommendations regardless of whether they have been exposed to occupational risk for COVID-19. CONCLUSIONS: The healthcare workers' high level of adherence to infection prevention practices at this hospital helped reduce and minimize their occupational exposure to COVID-19.

Flight attendant occupational nutrition and lifestyle factors associated with COVID-19 incidence.

In the era of COVID-19, essential workers are plagued with unforeseen and obfuscated challenges. Flight attendants are a unique subgroup of essential workers who face a multitude of health risks attributed to occupational exposures that are accentuated by the COVID-19 pandemic. Such risks can be ameliorated with strategies that target factors which enhance COVID-19 risk, including modifiable factors of diet and lifestyle. The aim of this cross-sectional study is to detect occupational dietary and lifestyle factors which could increase COVID-19 incidence amongst flight attendants. To identify potential risk factors, a questionnaire was administered to eighty-four flight attendants and examined the participants' diet and lifestyle, and COVID-19 incidence. Descriptive statistics and logistic regression indicated that the participants' perceived dietary quality at work (p = 0.003), sleep disruptions which impacted their consumption of a healthy diet (p = 0.013), job tenure (OR: 0.67, 95% CI: 0.46:0.98) and frequency of reported cold/flu (OR: 1.49, 95% CI: 1.014-2.189) were all factors associated with confirmed/suspected COVID-19 incidence. This study also revealed that a lack of infrastructure for food storage and time limitations are considerable occupational barriers for flight attendants to consume healthy foods. Additional investigation can further elucidate these relationships and related solutions to mitigate COVID-19 risk in the future.

Humoral immune response to SARS-CoV-2 in five different groups of individuals at different environmental and professional risk of infection.

It is partially unknown whether the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection persists with time. To address this issue, we detected the presence of SARS-CoV-2 antibodies in different groups of individuals previously diagnosed with COVID-19 disease (group 1 and 2), or potentially exposed to SARS-CoV-2 infection (group 3 and 4), and in a representative group of individuals with limited environmental exposure to the virus due to lockdown restrictions (group 5). The primary outcome was specific anti-SARS-CoV-2 antibodies in the different groups assessed by qualitative and quantitative analysis at baseline, 3 and 6 months follow-up. The seroconversion rate at baseline test was 95% in group 1, 61% in group 2, 40% in group 3, 17% in group 4 and 3% in group 5. Multivariate logistic regression analysis revealed male gender, close COVID-19 contact and presence of COVID-19 related symptoms strongly associated with serological positivity. The percentage of positive individuals as assessed by the qualitative and quantitative tests was superimposable. At the quantitative test, the median level of SARS-CoV-2 antibody levels measured in positive cases retested at 6-months increased significantly from baseline. The study indicates that assessing antibody response to SARS-CoV-2 through qualitative and quantitative testing is a reliable disease surveillance tool.

Reaction Times among Batik Workers: The Influence of Gender and Occupational Lead Exposure.

(1) Background: Neglected occupational health and safety aspects in batik industries cause their workers to have an increased risk of lead exposure. The effect of occupational lead exposure on neurocognitive performance is inconclusive. Therefore, we conducted an observational study to examine the difference in simple reaction time between lead-exposed batik workers and non-exposed referents. (2) Methods: This cross-sectional study was conducted in seven batik enterprises in Lendah District, Indonesia, excluding workers with medical conditions impairing reaction time. Simple reaction time tests were conducted using an online tool. Two-way model ANCOVAs examined interactions between gender and job types on the mean differences in reaction time. (3) Results: After controlling for age and body mass index, we observed longer reaction times among lead-exposed batik workers than non-exposed referents with an adjusted mean difference of 0.19 (95% CI: 0.016-0.368) seconds. A more prominent detrimental effect of lead exposure on reaction time among female workers than among male workers was observed. (4) Conclusions: Our results suggest that occupational lead exposure could contribute to longer reaction time, notably among female workers. Thus, occupational health and safety precautions are vital to protect batik workers and preserve their important contributions to cultural heritage.

SARS-CoV-2 antibodies in Ontario health care workers during and after the first wave of the pandemic: a cohort study.

BACKGROUND: Health care workers have a critical role in the pandemic response to COVID-19 and may be at increased risk of infection. The objective of this study was to assess the seroprevalence of SARS-CoV-2 immunoglobulin G (IgG) antibodies among health care workers during and after the first wave of the pandemic. METHODS: We conducted a prospective multicentre cohort study involving health care workers in Ontario, Canada, to detect IgG antibodies against SARS-CoV-2. Blood samples and self-reported questionnaires were obtained at enrolment, at 6 weeks and at 12 weeks. A community hospital, tertiary care pediatric hospital and a combined adult-pediatric academic health centre enrolled participants from Apr. 1 to Nov. 13, 2020. Predictors of seropositivity were evaluated using a multivariable logistic regression, adjusted for clustering by hospital site. RESULTS: Among the 1062 health care workers participating, the median age was 40 years, and 834 (78.5%) were female. Overall, 57 (5.4%) were seropositive at any time point (2.5% when participants with prior infection confirmed by polymerase chain reaction testing were excluded). Seroprevalence was higher among those who had a known unprotected exposure to a patient with COVID-19 (p < 0.001) and those who had been contacted by public health because of a nonhospital exposure (p = 0.003). Providing direct care to patients with COVID-19 or working on a unit with a COVID-19 outbreak was not associated with higher seroprevalence. In multivariable logistic regression, presence of symptomatic contacts in the household was the strongest predictor of seropositivity (adjusted odds ratio 7.15, 95% confidence interval 5.42-9.41). INTERPRETATION: Health care workers exposed to household risk factors were more likely to be seropositive than those not exposed, highlighting the need to emphasize the importance of public health measures both inside and outside of the hospital.

Are doctors protected enough during COVID-19 in South Asia?

BACKGROUND: The highly contagious nature of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) places physicians in South Asia at high risk of contracting the infection. Accordingly, we conducted this study to provide an updated account of physician deaths in South Asia during the COVID-19 pandemic and to analyze and compare the different characteristics associated with physician mortality amongst the countries of the region. METHODS: We performed a cross-sectional study by using published news reports on the websites of news agencies from 9 selected countries in South Asia. Our study included only those physicians and doctors who died after contracting COVID-19 from their respective workplaces. All available data about the country of origin, type of, sex, age, medical or surgical specialty, and date of death were included. RESULTS: The total number of physician deaths reported due to COVID-19 in our study was 170, with half (87/170, 51%) of the deaths reported from Iran. Male physician deaths were reported to be 145 (145/170 = 85%). Internal Medicine (58.43%) was the most severely affected sub-specialty. The highest physician mortality rate in the general population recorded in Afghanistan (27/1000 deaths). General physicians from India [OR = 11.00(95% CI = 1.06-114.08), p = 0.045] and public sector medical practitioners from Pakistan [aOR = 4.52 (95% CI = 1.18-17.33), p = 0.028] were showing significant mortality when compared with other regions in multivariate logistic regression. CONCLUSION: An increased number of physician deaths, owing to COVID-19, has been shown in South Asia. This could be due to decreased personal protective equipment and the poor health care management systems of the countries in the region to combat the pandemic. Future studies should provide detailed information of characteristics associated with physician mortalities along with the main complications arising due to the virus.

SARS-CoV-2 Exposure and Infection Among Health Care Personnel - Minnesota, March 6-July 11, 2020.

Health care personnel (HCP) are at increased risk for infection with SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), as a result of their exposure to patients or community contacts with COVID-19 (1,2). Since the first confirmed case of COVID-19 in Minnesota was reported on March 6, 2020, the Minnesota Department of Health (MDH) has required health care facilities* to report HCP† exposures to persons with confirmed COVID-19 for exposure risk assessment and to enroll HCP with higher-risk exposures into quarantine and symptom monitoring. During March 6-July 11, MDH and 1,217 partnering health care facilities assessed 21,406 HCP exposures; among these, 5,374 (25%) were classified as higher-risk§ (3). Higher-risk exposures involved direct patient care (66%) and nonpatient care interactions (e.g., with coworkers and social and household contacts) (34%). Within 14 days following a higher-risk exposure, nearly one third (31%) of HCP who were enrolled in monitoring reported COVID-19-like symptoms,¶ and more than one half (52%) of enrolled HCP with symptoms received positive SARS-CoV-2 test results. Among all HCP with higher-risk exposures, irrespective of monitoring enrollment, 7% received positive SARS-CoV-2 test results. Compared with HCP with higher-risk exposures working in acute care settings, those working in congregate living or long-term care settings more often returned to work (57%), worked while symptomatic (5%), and received a positive test result (10%) during 14-day postexposure monitoring than did HCP working outside of such settings. These data highlight the need for awareness of nonpatient care SARS-CoV-2 exposure risks and for targeted interventions to protect HCP, in addition to residents, in congregate living and long-term care settings. To minimize exposure risk among HCP, health care facilities need improved infection prevention and control, consistent personal protective equipment (PPE) availability and use, flexible sick leave, and SARS-CoV-2 testing access. All health care organizations and HCP should be aware of potential exposure risk from coworkers, household members, and social contacts.

Risks of COVID-19 by occupation in NHS workers in England.

OBJECTIVE: To quantify occupational risks of COVID-19 among healthcare staff during the first wave (9 March 2020-31 July 2020) of the pandemic in England. METHODS: We used pseudonymised data on 902 813 individuals employed by 191 National Health Service trusts to explore demographic and occupational risk factors for sickness absence ascribed to COVID-19 (n=92 880). We estimated ORs by multivariable logistic regression. RESULTS: With adjustment for employing trust, demographic characteristics and previous frequency of sickness absence, risk relative to administrative/clerical occupations was highest in 'additional clinical services' (care assistants and other occupations directly supporting those in clinical roles) (OR 2.31 (2.25 to 2.37)), registered nursing and midwifery professionals (OR 2.28 (2.23 to 2.34)) and allied health professionals (OR 1.94 (1.88 to 2.01)) and intermediate in doctors and dentists (OR 1.55 (1.50 to 1.61)). Differences in risk were higher after the employing trust had started to care for documented patients with COVID-19, and were reduced, but not eliminated, following additional adjustment for exposure to infected patients or materials, assessed by a job-exposure matrix. For prolonged COVID-19 sickness absence (episodes lasting >14 days), the variation in risk by staff group was somewhat greater. CONCLUSIONS: After allowance for possible bias and confounding by non-occupational exposures, we estimated that relative risks for COVID-19 among most patient-facing occupations were between 1.5 and 2.5. The highest risks were in those working in additional clinical services, nursing and midwifery and in allied health professions. Better protective measures for these staff groups should be a priority. COVID-19 may meet criteria for compensation as an occupational disease in some healthcare occupations. TRIAL REGISTRATION NUMBER: ISRCTN36352994.

SARS-CoV-2 antibody seroprevalence among firefighters in Orange County, California.

OBJECTIVES: We conducted serological SARS-CoV-2 antibody testing from October to November 2020 to estimate the SARS-CoV-2 seroprevalence among firefighters/paramedics in Orange County (OC), California. METHODS: OC firefighters employed at the time of the surveillance activity were invited to participate in a voluntary survey that collected demographic, occupational and previous COVID-19 testing data, and a SARS-CoV-2 immunoglobulin (Ig)G antibody blood test. We collected venous blood samples using mobile phlebotomy teams that travelled to individual fire stations, in coordination with an annual tuberculosis testing campaign for firefighters employed by OC Fire Authority (OCFA), and independently for firefighters employed by cities. We estimated seroprevalence and assessed several potential predictors of seropositivity. RESULTS: The seroprevalence was 5.3% among 923 OCFA personnel tested, with 92.2% participating. Among firefighters self-reporting a previous positive COVID-19 antibody or PCR test result, twenty-one (37%) did not have positive IgG tests in the current serosurvey. There were no statistically significant differences in demographic characteristics between cases and non-cases. Work city was a significant predictor of case status (p=0.015). Seroprevalence (4.8%) was similar when aggregated across seven city fire departments (42%-65% participation). In total, 1486°C fire personnel were tested. CONCLUSION: Using a strong serosurvey design and large firefighter cohort, we observed a SARS-CoV-2 IgG seroprevalence of 5.3%. The seroprevalence among OC firefighters in October 2020 was lower than the general county population estimated seroprevalence (11.5%) in August. The difference may be due in part to safety measures taken by OC fire departments at the start of the pandemic, as well as differences in antibody test methods and/or duration of antibody response.

Temporal Trends in COVID-19 Incidence in Two Healthcare Worker Cohorts.

BACKGROUND: Health care workers (HCWs) experience increased occupational risk of contracting COVID-19, with temporal trends that might inform surveillance. METHODS: We analyzed data from a Veterans Affairs hospital-based COVID-19 worker telephone hotline collected over 40 weeks (2020). We calculated the proportion of COVID-19+ cases among persons-under-investigation (PUIs) for illness compared to rates from a nearby large university-based health care institution. RESULTS: We observed 740 PUIs, 65 (8.8%) COVID-19+. Time trends were similar at the study and comparison hospitals; only for the first of 10 four-week observation periods was the ratio for observed to expected COVID-19+ significant (P < 0.001). DISCUSSION: These data suggest that employee health COVID-19+ to PUI ratios could be utilized as a barometer of community trends. Pooling experience among heath care facilities may yield insights into occupational infectious disease outbreaks.

Epidemiology of asymptomatic and symptomatic Coronavirus Disease 2019 confirmed cases in the Emirate of Abu Dhabi, United Arab Emirates: Observational study.

ABSTRACT: This study was conducted to describe demographics, clinical features, and outcomes of 3827 confirmed cases of Coronavirus Disease 2019 between March 12 and April 22, 2020 in the Emirates of Abu Dhabi, United Arab Emirates (UAE).Data were extracted from the Infectious Diseases Notification Surveillance System of the Department of Health. The descriptive analysis was done using Statistical Package for Social Sciences v26 and reported according to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement.We analyzed 3827 cases; 82% were men, 18% women, 14% UAE citizens, and 86% were of other nationalities. Most cases (72%) had lower exposure to low-risk occupations of infectious disease as per the classification of the department of health while high exposure risk occupations, which included healthcare worker accounts only for 3%. While 43% of cases were asymptomatic, 57% displayed symptoms, which were mostly mild. Only 12% of patients had comorbidities, which were significantly higher in men (9%) than women (3%). Among those who have comorbid conditions; hypertension (27%) and diabetes (21%) were the most common comorbidities. Viral pneumonia (11%) was the most common sequela documented in records. Only 51 patients (4%) required admission to the intensive care units, and 4 patients died (0.1%).The significant number of asymptomatic patients was identified by active case finding and contact tracing from the early period of the epidemic. A small percentage of severe, critical cases, and death reported in the Emirate of Abu Dhabi which may have been due to public health measures implemented for early detection, contact tracing, and treatment.

Implications of Cloth COVID Masks for Size Distribution of Inhaled Plutonium, Respiratory Deposition, and Fecal Bioassay Monitoring.

ABSTRACT: This work considers the implications of cloth masks due to the COVID-19 pandemic on suspected plutonium inhalations and dose assessment. In a plutonium inhalation scenario, the greater filtration efficiency for large particles exhibited by cloth masks can reduce early fecal excretion without a corresponding reduction in dose. For plutonium incidents in which cloth masks are worn, urinary excretion should be the preferred method of inferring dose immediately after the inhalation, and fecal excretion should be considered unreliable for up to 10 days.

A rapid scoping review of COVID-19 and vulnerable workers: Intersecting occupational and public health issues.

BACKGROUND: This article reports the results of a rapid scoping review of the literature on COVID-19 transmission risk to workers in essential sectors such as retail, health care, manufacturing, and agriculture, and more particularly the experiences of workers in precarious employment and social situations. METHODS: Following scoping review methods, we included 30 studies that varied in terms of methodology and theoretical approaches. The search included peer-reviewed articles and grey literature published between March and September 2020. RESULTS: Based on the studies reviewed, we found that COVID-19 infection and death rates increased not only with age and comorbidities, but also with discrimination and structural inequities based on racism and sexism. Racial and ethnic minority workers, including migrant workers, are concentrated in high-risk occupations and this concentration is correlated to lower socioeconomic conditions. The COVID-19 pandemic appears in the occupational health and safety spotlight as an exacerbator of already existing socioeconomic inequalities and social inequalities in health, especially in light of the intersection of issues related to racism, ethnic minority status, and sexism. CONCLUSIONS: This review provides early evidence about the limitations of institutions' responses to the pandemic, and their capacity to provide a safe and decent working environment for all workers, regardless of their employment status or the social protections they may enjoy under normal circumstances. It is also important to think about these issues in the postpandemic context, when conditions of precariousness and vulnerability persist and possibly worsen.

The Spread of COVID-19 Among 15,000 Physical Therapists in Italy: A Cross-Sectional Study.

OBJECTIVES: The purpose of this study was to explore the prevalence, personal- and work-related exposures, and signs and symptoms among physical therapists during the first wave of coronavirus disease 2019 (COVID-19) in Italy. METHODS: This cross-sectional, survey-based study collected demographic and exposure data from physical therapists from April to May 2020. All physical therapists working in inpatient and outpatient care in Italy were eligible. A self-administered questionnaire was distributed among all eligible physical therapists to collect (1) demographic characteristics, (2-3) personal- and work-related exposures, and (4) signs and symptoms of COVID-19. Factors associated with a COVID-19-positive nasopharyngeal swab (NPS) were explored through logistic regression models and multivariate methods. RESULTS: A total of 15,566 respondents completed the survey, with a response rate of 43.3%, achieving high statistical precision (99% CI, 1% type I error). Among physical therapists who received NPS testing, 13.1% (95% CI = 12.1-14.1%) had a positive result, with a peak reached in March 2020 (36%). The top 5 symptoms were fatigue and tiredness (69.1%), loss of smell (64.5%), aches and pains (60.8%), loss of taste (58.3%), and headache (51.1%). No symptoms were reported by 8.9%. Working in a health care institution (odds ratio [OR] = 12.0; 95% CI = 7.8-18.4), being reallocated to a different unit (OR = 1.9; 95% CI = 1.3-2.7), and changing job tasks (OR = 1.6; 95% CI = 1.2-2.3) increased the risk of being COVID-19 positive. In therapists with a confirmed diagnosis of COVID-19, comorbidities were associated with male sex and age older than 51 years. CONCLUSION: During the first wave in Italy, almost 1 out of 7 physical therapists tested positive on the COVID-19 NPS test. Considering personal- and work-related exposures, health care organizations should adopt prevention measures and adequate preparedness to prevent high rate of infections during future pandemics. IMPACT: This is the largest investigation about the spread of and main risk factors for COVID-19 in the physical therapy field.

SARS-CoV-2 Seroprevalence Among Healthcare Workers by Workplace Exposure Risk in Kashmir, India.

BACKGROUND: SARS-CoV-2 infection (COVID-19) poses a tremendous challenge to healthcare systems across the globe. Serologic testing for SARS-CoV-2 infection in healthcare workers (HCWs) may quantify the rate of clinically significant exposure in an institutional setting and identify those HCWs who are at greatest risk. METHODS: We conducted a survey and SARS-CoV-2 serologic testing among a convenience sample of HCWs from 79 non-COVID and 3 dedicated COVID hospitals in District Srinagar of Kashmir, India. In addition to testing for the presence of SARS-CoV-2-specific immunoglobulin G (IgG), we collected information on demographics, occupational group, influenza-like illness (ILI) symptoms, nasopharyngeal reverse transcription polymerase chain reaction (RT-PCR) testing status, history of close unprotected contacts, and quarantine/travel history. RESULTS: Of 7,346 eligible HCWs, 2,915 (39.7%) participated in the study. The overall prevalence of SARS-CoV-2-specific IgG antibodies was 2.5% (95% CI, 2.0%-3.1%), while HCWs who had ever worked at a dedicated COVID-19 hospital had a substantially lower seroprevalence of 0.6% (95% CI, 0.2%-1.9%). Higher seroprevalence rates were observed among HCWs who reported a recent ILI (12.2%), a positive RT-PCR (27.6%), a history of being put under quarantine (4.9%), and a history of close unprotected contact with a person with COVID-19 (4.4%). Healthcare workers who ever worked at a dedicated COVID-19 hospital had a lower multivariate-adjusted risk of seropositivity (odds ratio, 0.21; 95% CI, 0.06-0.66). CONCLUSIONS: Our investigation suggests that infection-control practices, including a compliance-maximizing buddy system, are valuable and effective in preventing infection within a high-risk clinical setting. Universal masking, mandatory testing of patients, and residential dormitories for HCWs at COVID-19-dedicated hospitals is an effective multifaceted approach to infection control. Moreover, given that many infections among HCWs are community-acquired, it is likely that the vigilant practices in these hospitals will have spillover effects, creating ingrained behaviors that will continue outside the hospital setting.