Asymptomatic Employees Research Articles

Laboratory Examinations of Employees of Muhammadiyah University General Hospital of Malang Infected With COVID-19

COVID-19 can symptomatically and asymptomatically affect patients. Asymptomatic cases have become a particular concern for public health in the COVID-19 pandemic. One of the simple tests for COVID-19 is the complete blood count that can predict systemic inflammation and disease severity. The description of laboratory tests in asymptomatic COVID-19 patients is rarely reported. This study aimed to compare the laboratory test results of both symptomatic and asymptomatic COVID-19 employees of the Muhammadiyah University General Hospital of Malang. Data were taken from medical records. Diagnoses of COVID-19 were confirmed by nasopharynx-oropharynx PCR swab. Patient characteristics included age, gender, and values of hemoglobin, leukocytes, neutrophils, lymphocytes, platelets, NLR and CRP from two different groups: symptomatic and asymptomatic infected employees. There were 104 COVID-19 infected employees at the hospital from April 2020 to February 2021. Female infected employees (52.9%) were more numerous male infected employees. Employees aged 21-30 years accounted for 53.84% of the total cases. The numbers of symptomatic and asymptomatic employees were 10 employees (9.6%) and 94 employees (90.4%), respectively. There was a significant difference between the symptomatic and asymptomatic groups in the numbers of lymphocytes (p = 0.03) and CRP (p = 0.046). There were no significant differences in the other laboratory results. Lymphopenia and increased CRP numbers more often occurred in the symptomatic group compared to the asymptomatic group. Therefore, these parameters can be an indicator for predicting disease severity. However, further research is needed with a bigger sample.
 Keywords: COVID-19, symptomatic, asymptomatic, Muhammadiyah University General Hospital of Malang

SARS-CoV-2 rapid antigen screening of asymptomatic employees: a pilot project.

SettingRapid antigen screening can be effective in identifying infectious individuals in occupational settings to reduce transmission and outbreaks. We report results from a pilot project at the Greater Toronto Airports Authority (GTAA) and describe the operationalization. Toronto Pearson is a large international airport encompassing over 400 employers and, pre-pandemic, with approximately 50,000 employees.InterventionAn employee screening program was piloted between March 8 and May 28, 2021, to implement rapid antigen testing for asymptomatic employees. Recruitment targeted enrolment of 400 employees and yielded participation of 717 from 58 companies. Employees were recommended to book three times per week for nasal swabs on site, and were tested on the Abbot PanbioTM rapid antigen test. No action was taken from a negative result, and if positive, the employee was told to isolate at home and obtain a confirmatory polymerase chain reaction test.OutcomesA total of 5117 tests were performed on 717 individuals over 12 weeks; 5091 tests were negative (99.5%), and 22 individuals tested positive (3.1% positivity rate). One hundred twenty-four (17%) completed the post-participation survey. All respondents reported that testing did not change their behaviour at work with respect to public health recommendations, and only 1 (1%) reported behaviour change outside of work (socializing with family) as a result of the program.ImplicationsThis pilot program identified 22 (3.1%) potentially infectious employees. Onsite testing was feasible and highly accepted by this group of employees who completed the survey. Education resulted in reasonable uptake and no substantial change in behaviour, although the survey response rate may limit generalizability. Home-based testing may facilitate larger recruitment.

Multijurisdictional Outbreak of Enterohemorrhagic Escherichia coli O157 Caused by Consumption of Ready-to-Eat Grilled Skewered Meat in Niigata, Japan.

Enterohemorrhagic Escherichia coli O157 (EHEC) causes severe complications such as hemolytic uremic syndrome. Contaminated ready-to-eat (RTE) food is one of the vehicles of multijurisdictional outbreaks of foodborne disease worldwide. Multijurisdictional (covering cities, towns, and villages) outbreaks of EHEC are usually linked to an increase in cases, and here we describe such an outbreak involving 29 cases in October 2017 in the Niigata Prefecture. After prefecture-wide active case finding, we conducted a case-control study of 29 cases with eligible data who tested positive for EHEC. To determine the association of the outbreak with risk factors, we compared these cases with 38 controls selected from family and acquaintances who were both symptom free and tested negative for EHEC. The largest number of cases was in the 20-29-year age group (7/29; 24%) and most were women (20/29; 69%). All 29 cases had an identical or similar multilocus variable number tandem-repeat analysis (MLVA) profile. Of these, 76% (22/29) had consumed some type of grilled skewered meat. Also, 69% (20/29) had consumed grilled skewered meat produced by company X. EHEC infection was strongly associated with the consumption of grilled skewered meat produced by any food processing company (odds ratio [OR] = 11.8, confidence interval [95% CI]: 3.7-37.4) and by company X (OR = 9.8, 95% CI: 3.2-30.7). At company X, the skewered meat was grilled to 95°C and then removed from the grilling area to meat trays. The meat trays were not sufficiently washed and disinfected. Testing indicated that the facility was negative for EHEC but four asymptomatic employees tested positive for EHEC. Company X was temporarily closed and voluntarily recalled the foods. We recommend that all employees sufficiently wash and disinfect meat trays to prevent contamination of RTE food, avoid cross-contamination of grilled skewered meat through the environment by regularly cleaning the facility, and appropriately practice self-health care.

An adaptive, asymptomatic SARS-CoV-2 workforce screening program providing real-time, actionable monitoring of the COVID-19 pandemic.

COVID-19 remains a challenge worldwide, and testing of asymptomatic individuals remains critical to pandemic control measures. Starting March 2020, a total of 7497 hospital employees were tested at least weekly for SARS CoV-2; the cumulative incidence of asymptomatic infections was 5.64%. Consistently over a 14-month period half of COVID-19 infections (414 of 820, total) were detected through the asymptomatic screening program, a third of whom never developed any symptoms during follow-up. Prompt detection and isolation of these cases substantially reduced the risk of potential workplace and outside of workplace transmission. COVID-19 vaccinations of the workforce were initiated in December 2020. Twenty-one individuals tested positive after being fully vaccinated (3.9 per 1000 vaccinated). Most (61.9%) remained asymptomatic and in majority (75%) the virus could not be sequenced due to low template RNA levels in swab samples. Further routine testing of vaccinated asymptomatic employees was stopped and will be redeployed if needed; routine testing for those not vaccinated continues. Asymptomatic SARS-CoV-2 testing, as a part of enhanced screening, monitors local dynamics of the COVID-19 pandemic and can provide valuable data to assess the ongoing impact of COVID-19 vaccination and SARS-CoV-2 variants, inform risk mitigation, and guide adaptive, operational planning including titration of screening strategies over time, based on infection risk modifiers such as vaccination.

Systematic on-site testing for SARS-CoV-2 infection among asymptomatic essential workers in Montréal, Canada: a prospective observational and cost-assessment study

Background:Essential workers are at increased risk for SARS-CoV-2 infection. We aimed to estimate the yield, acceptability and cost of systematic workplace-based testing of asymptomatic essential workers for SARS-CoV-2 infection.Methods:From Jan. 27 to Mar. 12, 2021, we prospectively recruited non–health care essential businesses in Montréal, Canada, through email or telephone contact. Two trained mobile teams, each composed of 2 non–health care professionals, visited businesses. Consenting asymptomatic employees provided saline gargle samples under supervision. Samples were analyzed by means of reverse transcription polymerase chain reaction (RT-PCR). At businesses with outbreaks (≥ 2 participants with a positive result), we retested all participants with a negative result on initial testing. Our primary outcomes were yield (proportion of test results that were positive), acceptability (proportion of participants estimated to be present at the business who agreed to participate) and costs (including training, sample collection and analysis, and communicating results). Our secondary outcome was identification of factors associated with a positive test result on multivariable logistic regression.Results:Of the 366 businesses contacted, 69 (18.8%) agreed to participate. Nineteen businesses (28%) were manufacturers or suppliers, 12 (17%) were in auto sales or repair, and 11 (16%) were in childcare; the corresponding number of employees was 1225, 242 and 113. The median number of participants per business was 13 (interquartile range [IQR] 8–22). Of an estimated 2348 employees on site, 2128 (90.6%) participated (808 [38.0%] female, median age 48 [IQR 37–57] yr). Of the 2626 tests performed, 53 (2.0%) gave a positive result. Self-reported nonwhite ethnicity (adjusted odds ratio [OR] 3.7, 95% confidence interval [CI] 1.4–9.9) and a negative SARS-CoV-2 test result before the study (adjusted OR 0.4, 95% CI 0.2–0.8) were associated with a positive test result. Five businesses were experiencing an outbreak; at these businesses, 40/917 participants (4.4%) had a positive result on the initial test. We repeated testing for employees with initially negative results at 3 of these businesses over 2–3 weeks: 8/350 participants (2.3%) had a positive result on the second test, and none had a positive result on the third and fourth tests; no employer reported new positive results after our final visit (up to Mar. 26, 2021). At the remaining 64 businesses, 1211 participants were tested once, of whom 5 (0.4%) had a positive result. The per-person RT-PCR cost was $34, and all other costs, $8.67.Interpretation:On-site saline gargle sampling of essential workers for SARS-CoV-2 testing was acceptable and of modest cost, and appears most useful in the context of outbreaks. This sampling strategy should be evaluated further as a component of efforts to prevent SARS-CoV-2 transmission. Preprint:medRxiv — doi:10.1101/2021.05.12.21256956

The Diagnostic Accuracy of SARS-CoV-2 Rapid Antibody Tests among Asymptomatic Employees Returning to Work During General Community Quarantine Period (June 1 to July 31, 2020)

Objectives. The study was done to determine the diagnostic accuracy of rapid antibody tests (RATs) in detecting SARS-CoV-2 infection among asymptomatic employees returning to work. The study also aimed to determine the prevalence of asymptomatic RT-PCR-confirmed COVID-19 infection among these workers. Methods. The study was a retrospective cohort of asymptomatic employees involved in the manufacturing, marketing, and sales of pharmaceutical, consumer, and animal products in the Philippines. They underwent screening for COVID-19 using both rapid antibody and RT-PCR tests as part of the return-to-work company policy from June 1 to July 31, 2020. The sensitivity and specificity of the RATs were computed using RT-PCR as the reference standard. The prevalence of RT-PCR positive COVID-19 infections among asymptomatic returning workers was also determined. Results. Asymptomatic workers (n=5,585) were simultaneously tested for COVID-19 using RAT and RT-PCR. The sensitivity of a positive IgG and IgM was 23.9 (95% CI: 22.8 – 25.0), while the specificity was 93.3 (95% CI: 92.6 - 93.9). The prevalence of RT-PCR identified COVID-19 infection among asymptomatic workers was 4.9% (95% CI: 4.4 – 5.5). Conclusion. The utility of RATs as a screening tool to detect asymptomatic COVID-19 individuals is limited due to its low sensitivity compared to RT-PCR.

Effect of Knowledge/Practice of COVID-19 Prevention Measures on Return-to-Work Concerns; Attitudes About the Efficacy of Traditional Chinese Medicine: Survey on Supermarket Staff in Huanggang, China.

Objective: The objective of this study was to investigate how knowledge and practice of coronavirus disease 2019 (COVID-19) prevention measures affected concerns about returning to work among supermarket staff. Attitudes about the ability of traditional Chinese medicine (TCM) to prevent COVID-19 were also assessed.Methods: A cross-sectional study was conducted in Huanggang, Hubei Province, China from April 23 to 25, 2020. Participants were invited to fill out an electronic questionnaire on their cell phones.Results: The results showed that from 2,309 valid questionnaires, 61.5% of participants were concerned about resuming work. Major concerns included asymptomatic infection (85.01%) and employees gathering in the workplace (78.96%). Multivariate logistic regression indicated that the female gender, having school-aged children and pregnancy were risk factors for being concerned about resuming work, while good knowledge and practice of preventive measures were protective factors. Knowledge and practice of preventive measures were positively correlated. Among preventive measures, the highest percentage of participants knew about wearing masks and washing hands. Meanwhile, 65.8% of participants expressed confidence in the ability of TCM to prevent COVID-19, where 74 and 51.3% thought there was a need and a strong need, respectively, for preventive TCM-based products. Among them, 71.5% preferred oral granules. Regarding TCM as a COVID-19 preventative, most were interested in information about safety and efficacy.Conclusion: These findings suggested that promoting knowledge and practices regarding COVID-19 prevention can help alleviate concerns about returning to work. Meanwhile, TCM can feasibly be accepted to diversify COVID-19 prevention methods.Clinical Trial Registration:http://www.chictr.org.cn/, identifier: ChiCTR2000031955.

Protracted, Intermittent Outbreak of Salmonella Mbandaka Linked to a Restaurant - Michigan, 2008-2019.

In 2018, Michigan public health officials determined that a single restaurant in southwest Michigan was the source for a protracted, intermittent outbreak of Salmonella enterica serotype Mbandaka infections occurring since 2008. Isolates from 36 infected persons shared two highly related pulsed-field gel electrophoresis (PFGE) patterns and highly related whole genome sequencing (WGS) subtypes. The initial focus of the local public health investigation on food items rather than food sources (i.e., restaurants) through a questionnaire, difficulty in food history recollection among ill persons, and sporadic case identification over periods from months to years contributed to delayed source identification. The Kalamazoo County Health and Community Services Department (KHCSD) and the Michigan Department of Health and Human Services (MDHHS) collected clinical specimens, performed multiple rounds of environmental testing, and conducted multiple regulatory visits, and based on accumulated findings over 10 years, identified the restaurant source. A 2018 investigation by KCHCSD and MDHHS found that environmental samples and stool specimens from asymptomatic restaurant employees tested positive for the Salmonella Mbandaka outbreak strain. A complex association between the restaurant environment and employees resulted in patron illnesses. Environmental health interventions, facility renovation, asymptomatic employee exclusions, employee health monitoring, and recurrent facility environmental sampling measures were implemented. As a result of ongoing cases and environmental persistence of Salmonella Mbandaka, the restaurant closed permanently in 2018. Restaurant employee stool testing and environmental sampling for Salmonella early during the investigation of confirmed Salmonella cases linked to a restaurant enhances source identification. Exclusion or restriction of asymptomatic food workers with stool-positive nontyphoidal Salmonella should be considered part of restaurant outbreak mitigation.

Transmission of SARS-CoV-2 in Inpatient and Outpatient Settings in a Veterans Affairs Health Care System.

BackgroundHealth care personnel and patients are at risk to acquire severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in health care settings, including in outpatient clinics and ancillary care areas.MethodsBetween May 1, 2020, and January 31, 2021, we identified clusters of 3 or more coronavirus disease 2019 (COVID-19) cases in which nosocomial transmission was suspected in a Veterans Affairs health care system. Asymptomatic employees and patients were tested for SARS-CoV-2 if they were identified as being at risk through contact tracing investigations; for 7 clusters, all personnel and/or patients in a shared work area were tested regardless of exposure history. Whole-genome sequencing was performed to determine the relatedness of SARS-CoV-2 samples from the clusters and from control employees and patients.ResultsOf 14 clusters investigated, 7 occurred in community-based outpatient clinics, 1 in the emergency department, 3 in ancillary care areas, and 3 on hospital medical/surgical wards that did not provide care for patients with known COVID-19 infection. Eighty-one of 82 (99%) symptomatic COVID-19 cases and 31 of 35 (89%) asymptomatic cases occurred in health care personnel. Sequencing analysis provided support for several transmission events between coworkers and in 2 cases supported transmission from health care personnel to patients. There were no documented transmissions from patients to personnel.ConclusionsClusters of COVID-19 with nosocomial transmission predominantly involved health care personnel and often occurred in outpatient clinics and ancillary care areas. There is a need for improved measures to prevent transmission of SARS-CoV-2 by health care personnel in inpatient and outpatient settings.

Rapid serological tests for SARS-CoV-2 IgG/IgM - not worth attention?

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome virus 2 (SARS-CoV-2) had spread worldwide since December 2019 and became a pandemic in March 2020. The diagnosis of an active infection is based on the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) from the nasopharyngeal swab specimen. The aim of the current analysis was to assess the usefulness of the rapid serological tests for diagnosing SARS-CoV-2 infections. The rapid serological tests detecting IgG/IgM antibodies for SARS-CoV-2 were voluntarily performed in asymptomatic employees of 2 companies. The examination was conducted at the date and time selected online by the study participants. The testing team consisted of 2 nurses collecting the samples and 1 doctor who interpreted the results. Each positive rapid test result was verified by an RT-PCR examination from a nasopharyngeal swab. The testing kits named Vazyme: 2019-nCoV IgG/IgM Detection Kit (Colloidal Gold-Based) were provided by the employer along with the manual and certificates. The overall interest in testing among employees was below the employer's expectations and reached 30% and 20% in each of the 2 companies, respectively. A total of 516 participants were included in the analysis. Ten positive results of the rapid tests were documented, including 7 for IgM and 3 for IgG antibodies. No positive result was confirmed by the detection of the genetic material of the SARS-CoV-2 by the RT-PCR examination. Herein, the authors demonstrated the uselessness of rapid serological tests performed in asymptomatic volunteers for diagnosing SARS-CoV-2 infections. Int J Occup Med Environ Health. 2021;34(2):203-9.

Implementation of measures to improve blood collection center employee safety and reduce callouts during the 2019 novel coronavirus pandemic.

BackgroundBlood collection center (BCC) employees are essential workers during the COVID‐19 pandemic. The employee callout rate, defined as the percentage of scheduled employees unable to report to work for any cause including COVID‐19 illness or asymptomatic quarantine, was tracked to determine the impact of safety measures including social distancing, masks, enhanced disinfection protocols, and temperature screening.Study design and methodsA contact tracing and quarantine program was implemented for all employees, followed by additional safety measures including social distancing, masks, enhanced disinfection protocols, and temperature screening. The weekly callout rate was tracked nationally for 19,517 BCC employees over 9 months, from March to December 2020.ResultsWeekly employee callout rates increased after implementation of the contact tracing program due to asymptomatic employees placed into COVID‐19‐related quarantine. Mobile collections callouts increased by nearly fivefold the pre‐pandemic baseline within the first 4 weeks, peaking at 9.7% in early April. Peaks for fixed site collections (5.0%) and manufacturing (6.7%) occurred nearly simultaneously. Shortly after implementation of all safety measures, the weekly callout rate declined for all three employee groups and has remained relatively stable with a mean callout rate of 4.3% for mobile collections, 2.4% for fixed site collections, and 3.7% for manufacturing despite further increase in new COVID‐19 cases in the United States.ConclusionCallouts for BCC employees during the COVID‐19 pandemic initially increased, but subsequently declined and stabilized after implementation of safety measures. Since multiple interventions were implemented simultaneously, it is not possible to determine the individual impact of each measure on callout rate.

Performance of the BinaxNOW coronavirus disease 2019 (COVID-19) Antigen Card test relative to the severe acute respiratory coronavirus virus 2 (SARS-CoV-2) real-time reverse transcriptase polymerase chain reaction (rRT-PCR) assay among symptomatic and asymptomatic healthcare employees.

The sensitivity of the BinaxNOW coronavirus disease 2019 (COVID-19) Ag Card test (BinaxNOW) was 51.6% among asymptomatic healthcare employees relative to real-time reverse transcriptase polymerase chain reaction (rRT-PCR). The odds of a positive BinaxNOW test decreased as cycle threshold value increased. BinaxNOW could facilitate rapid detection and isolation of asymptomatically infected persons in some settings while rRT-PCR results are pending.

463. Random Sampling of Asymptomatic Hospital Employees: A Period Prevalence Study

BackgroundNovel coronavirus disease 2019 (COVID-19) has had a significant impact on the work force in hospital settings. Despite rigorous screening practices implemented at many institutions, reports have documented transmission from asymptomatic and presymptomatic individuals in community environments. Evidence of nosocomial transmission between healthcare workers and patients in the early phase of the pandemic has further compounded the fears of safety in the workplace. We sought to determine the asymptomatic carriage rate of employees to inform messaging and response in the context of universal masking and eye protection.MethodsWe conducted a period prevalence study in asymptomatic hospital employees at a quaternary pediatric hospital during April to June 2020. Eligible employees included clinical staff, administrative staff, food services workers, and environmental services workers who had passed the temperature and symptom screening evaluation on entry to the campus. Samples were obtained from both nares of consenting individuals and ran daily on a validated polymerase chain reaction (PCR) platform.ResultsA total of 1394 employees consented to participate by June 15, 2020 and none of them had a positive result for COVID-19. Thus, the prevalence rate among asymptomatic employees was zero during this period (95%CI 0%-0.26%). Thirteen employees developed symptoms after initial enrollment and testing of which 1 tested positive for COVID-19. Based on these data, we estimate a monthly incidence rate of 0.8 new COVID-19 cases per 1000 asymptomatic employees (95%CI 0.2 - 4.4 per 1000). Of note, at the time of submission the R0 for our region was 1.4, and the prevalence of COVID-19 infection among symptomatic employees was 9.9% (68/686 tested in our system, 95%CI: 7.8%-12.3%).ConclusionWe did not identify any COVID-19-positive asymptomatic hospital employees who passed screening measures. This suggests very low risk of nosocomial transmission to other employees, patients, and families. Along with low community prevalence and capture of COVID-19-positive symptomatic employees, we could confidently advise staff that universal surgical masking and eye protection were likely adequate to prevent significant exposure.Disclosures All Authors: No reported disclosures

SARS-COV-2 Serological Profile in Healthcare Professionals of a Southern Italy Hospital.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the first coronavirus that has caused a pandemic. Assessing the prevalence of anti-SARS-CoV-2 in healthcare worker groups offers a unique opportunity to study the correlation between seroconversion and immunization because of their occupational exposure and a higher risk of contagion. The study enrolled 3242 asymptomatic employees of “Policlinico Riuniti”, Foggia. After the first screening, we collected sequential serum samples for up to 23 weeks from the same subjects. In order to perform a longitudinal follow-up study and get information about the titration of IgG levels, we analyzed data from subjects (33) with at least two consecutive serological IgG—positive tests; 62 (1.9%; 95% CI: 1.4–2.3) tested positive for at least one anti-SARS-CoV-2 antibody. The seroprevalence was lower in the high-risk group 1.4% (6/428; 95% CI: 0.5–2.6) vs. the intermediate-risk group 2.0% (55/2736; 95% CI: 1.5–2.5). Overall, within eight weeks, we detected a mean reduction of –17% in IgG levels. Our data suggest a reduction of about 9.27 AU/mL every week (R2 = 0.35, p = 0.0003). This study revealed the prevalence of SARS-CoV-2 antibodies among Foggia’s hospital healthcare staff (1.9%). Moreover, the IgG level reduction suggests that the serological response fades fast in asymptomatic infections.

Considerations for Pooled Testing of Employees for SARS-CoV-2.

Objectives:To identify important background information on pooled tested of employees that employers workers, and health authorities should consider.Methods:This paper is a commentary based on the review by the authors of pertinent literature generally from preprints in medrixiv.org prior to August 2020.Results/Conclusions:Pooled testing may be particularly useful to employers in communities with low prevalence of COVID-19. It can be used to reduce the number of tests and associated financial costs. For effective and efficient pooled testing employers should consider it as part of a broader, more comprehensive workplace COVID-19 prevention and control program. Pooled testing of asymptomatic employees can prevent transmission of SARS-CoV-2 and help assure employers and customers that employees are not infectious.

Amerindian genetic ancestry as a risk factor for tuberculosis in an amazonian population.

In recent years, the incidence of tuberculosis (TB) has declined worldwide, although this disease still occurs at relatively high rates in Amerindian populations. This suggests that the genetic ancestry of Amerindians may be an important factor in the development of infections, and may account for at least some of the variation in infection rates in the different populations. The present study investigated the potential influence of Amerindian genetic ancestry on susceptibility to tuberculosis in an Amazon population. The study included 280 patients diagnosed with tuberculosis and 138 asymptomatic hospital employees with no history of TB, but who were in contact with bacterially active TB patients. Ancestry analysis was run on a set of 61 Ancestry-Informative Markers to estimate European, African, and Amerindian genetic ancestry using STRUCTURE v2.2. The TB group had significantly higher Amerindian ancestry in comparison with the control group, and significantly lower European ancestry. Amerindian ancestry in the 20–60% range was found to be the principal risk factor for increased susceptibility to TB. The results of the study indicate that Amerindian ancestry is an important risk factor for susceptibility to TB in the admixed population of the Brazilian Amazon region.

Early Results from Severe Acute Respiratory Syndrome Coronavirus 2 Polymerase Chain Reaction Testing of Healthcare Workers at an Academic Medical Center in New York City.

Coronavirus disease 2019 (COVID-19) reverse-transcription polymerase chain reaction employee testing was implemented across New York University Langone Health. Over 8 weeks, 14 764 employees were tested; 33% of symptomatic employees, 8% of asymptomatic employees reporting COVID-19 exposure, and 3% of employees returning to work were positive. Positivity rates declined over time, possibly reflecting the importance of community transmission and efficacy of personal protective equipment.

Chembio DPP COVID-19 IgM/IgG Serological Testing: Laboratory Validation, Guidelines, and Recommendations.

On January 30, 2020, WHO declared COVID-19 a pandemic. In this article we describe our experience at Richmond University Medical Center with Chembio serological IgM, IgG testing. In this prospective cohort study of patients and hospital employees, we utilized Chembio COVID-19 IgM/IgG serological testing in addition to Cepheid RT-PCR analysis. We evaluated the performance of Chembio serological test for IgM and IgG as an employee screening tool in a community hospital setting. The total number of currently asymptomatic employees screened was 1,866 from the Richmond University Medical Center. The non-exposed group included 1,253 (67.1%) employees with no significant clinical history and non-reactive IgM and IgG antibodies. The convalescent group included 255 (13.7%) of the employees with elevation of IgG only, 18 (1%) employees with past history of positive PCR and COVID-19 who currently have non-reactive IgM and IgG antibodies or demonstrate elevated IgG only, followed by 3 employees (< 1%) with no past clinical history who demonstrated reactive IgM and IgG antibodies and negative follow up by PCR. The reported 14.9% exposure/convalescent rate is lower than the reported 20% by the Department of Health and Governor Andrew Cuomo and may represent a better utilization of personal protective equipment, better hand washing techniques, and better disinfection procedures combined with strict social distancing. Chembio's performance is satisfactory; however, hospitals must design their own policies addressing: who needs to be screened and who will interpret the results as well as constructing management algorithms for employees with no previous history and current double positive antibodies.

Norovirus shedding among symptomatic and asymptomatic employees in outbreak settings in Shanghai, China

BackgroundNorovirus (NoV) is recognized as a leading cause of acute gastroenteritis (AGE) outbreaks in settings globally. Studies have shown that employees played an important role in the transmission mode during some NoV outbreaks. This study aimed to investigate the prevalence of NoV infection and duration of NoV shedding among employees during NoV outbreaks, as well as factors affecting shedding duration.MethodsSpecimens and epidemiological data were collected from employees who were suspected of being involved in the transmission or with AGE symptoms during NoV outbreaks in Xuhui District, Shanghai, from 2015 to 2017. Specimens were detected using real-time RT-PCR to determine whether or not employees had become infected with NoV. Specimens were collected every 3–7 days from NoV-infected employees until specimens became negative for NoV.ResultsA total of 421 employees were sampled from 49 NoV outbreaks, and nearly 90% of them (377/421) were asymptomatic. Symptomatic employees showed significantly higher prevalence of NoV infection than asymptomatic ones (70.5% vs. 17.0%, P < 0.01). The average duration of NoV shedding was 6.9 days (95% confidence interval: 6.1–7.7 days) among 88 NoV-infected individuals, and was significantly longer in symptomatic individuals than in asymptomatic ones (9.8 days vs. 5.6 days, P < 0.01). In Cox proportional-hazards model, after adjusting age and gender, symptoms was the only factor associated with duration of NoV shedding.ConclusionsCompared with asymptomatic employees, symptomatic employees had higher prevalence of NoV infection and longer durations of NoV shedding. Since NoV shedding duration among NoV-infected employees tends to be longer than their isolation time during outbreaks, reinforcement of hygiene practices among these employees is especially necessary to reduce the risk of virus secondary transmissions after their return to work.

Investigation and environmental analysis of samples from outbreak of toxoplasmosis at research institution in Londrina, Paraná, Brazil, 2016.

The objective of this study was to report an outbreak of human toxoplasmosis at a research institution in Londrina, Paraná, from December 2015 to February 2016. Blood samples from 26 symptomatic individuals were collected and the microparticle chemiluminescence immunoassay was performed to detect IgM, IgG and specific IgG avidity test in the official laboratory. A total of 20 people with symptoms and serology compatible with acute toxoplasmosis (IgM positive and IgG with low avidity) were selected as cases, while 45 asymptomatic employees working in the same teams and during the same shifts were selected as controls. All the participants of the investigation answered an epidemiological questionnaire. Three samples of water and one sludge from the institution's supply cisterns, 10 soil samples, 11 plant samples, three cat fecal samples and one domestic feline cadaver were collected for analysis of the polymerase chain reaction (PCR) for T. gondii. After analyzing the epidemiological data, the consumption of vegetables in the restaurant of the institution was the only variable associated with the occurrence of the disease. In laboratory results, all the samples showed negative results to PCR. The rapid recognition of the outbreak, early notification and investigation could have broken the chain of transmission early, thus preventing the emergence of new cases. In addition, the adoption of good food handling practices could have prevented the occurrence of the outbreak.