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1.
Annals of Laboratory Medicine ; 41(6):577-587, 2021.
Article in English | CAB Abstracts | ID: covidwho-1408357

ABSTRACT

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assays have high clinical utility in managing the pandemic. We compared antibody responses and seroconversion of coronavirus disease 2019 (COVID-19) patients using different immunoassays.

2.
Ann Lab Med ; 41(6): 577-587, 2021 Nov 01.
Article in English | MEDLINE | ID: covidwho-1264321

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assays have high clinical utility in managing the pandemic. We compared antibody responses and seroconversion of coronavirus disease 2019 (COVID-19) patients using different immunoassays. METHODS: We evaluated 12 commercial immunoassays, including three automated chemiluminescent immunoassays (Abbott, Roche, and Siemens), three enzyme immunoassays (Bio-Rad, Euroimmun, and Vircell), five lateral flow immunoassays (Boditech Med, SD biosensor, PCL, Sugentech, and Rapigen), and one surrogate neutralizing antibody assay (GenScript) in sequential samples from 49 COVID-19 patients and 10 seroconversion panels. RESULTS: The positive percent agreement (PPA) of assays for a COVID-19 diagnosis ranged from 84.0% to 98.5% for all samples (>14 days after symptom onset), with IgM or IgA assays showing higher PPAs. Seroconversion responses varied across the assay type and disease severity. Assays targeting the spike or receptor-binding domain protein showed a tendency for early seroconversion detection and higher index values in patients with severe disease. Index values from SARS-CoV-2 binding antibody assays (three automated assays, one LFIA, and three EIAs) showed moderate to strong correlations with the neutralizing antibody percentage (r=0.517-0.874), and stronger correlations in patients with severe disease and in assays targeting spike protein. Agreement among the 12 assays was good (74.3%-96.4%) for detecting IgG or total antibodies. CONCLUSIONS: Positivity rates and seroconversion of SARS-CoV-2 antibodies vary depending on the assay kits, disease severity, and antigen target. This study contributes to a better understanding of antibody response in symptomatic COVID-19 patients using currently available assays.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Testing/methods , COVID-19/diagnosis , SARS-CoV-2/immunology , COVID-19/pathology , COVID-19/virology , Humans , Immunoassay , Immunoglobulin A/analysis , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Reagent Kits, Diagnostic , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Severity of Illness Index
3.
Osong Public Health Res Perspect ; 11(4): 259-264, 2020 Aug.
Article in English | MEDLINE | ID: covidwho-736998

ABSTRACT

This study describes the epidemiological characteristics of coronavirus disease 2019 (COVID-19) based on reported cases from long-term care facilities. As of April 20th, 2020, 3 long-term care facilities in a metropolitan area of South Korea had reported cases of COVID-19. These facilities' employees were presumed to be the sources of infection. There were 2 nursing hospitals that did not report any additional cases. One nursing home had a total of 25 cases, with an attack rate of 51.4% (95% CI 35.6-67.0), and a fatality rate of 38.9% (95% CI 20.3-61.4) among residents. The results from this study suggest that early detection and maintenance of infection control minimizes the risk of rapid transmission.

4.
Emerg. infect. dis ; 26(10), 2020.
Article in English | MEDLINE | ID: covidwho-706614

ABSTRACT

We analyzed reports for 59,073 contacts of 5,706 coronavirus disease (COVID-19) index patients reported in South Korea during January 20-March 27, 2020. Of 10,592 household contacts, 11.8% had COVID-19. Of 48,481 nonhousehold contacts, 1.9% had COVID-19. Use of personal protective measures and social distancing reduces the likelihood of transmission.

5.
J Clin Virol ; 129: 104502, 2020 08.
Article in English | MEDLINE | ID: covidwho-592138

ABSTRACT

BACKGROUND: Testing for COVID-19 remains limited in the United States and across the world. Poor allocation of limited testing resources leads to misutilization of health system resources, which complementary rapid testing tools could ameliorate. OBJECTIVE: To predict SARS-CoV-2 PCR positivity based on complete blood count components and patient sex. STUDY DESIGN: A retrospective case-control design for collection of data and a logistic regression prediction model was used. Participants were emergency department patients > 18 years old who had concurrent complete blood counts and SARS-CoV-2 PCR testing. 33 confirmed SARS-CoV-2 PCR positive and 357 negative patients at Stanford Health Care were used for model training. Validation cohorts consisted of emergency department patients > 18 years old who had concurrent complete blood counts and SARS-CoV-2 PCR testing in Northern California (41 PCR positive, 495 PCR negative), Seattle, Washington (40 PCR positive, 306 PCR negative), Chicago, Illinois (245 PCR positive, 1015 PCR negative), and South Korea (9 PCR positive, 236 PCR negative). RESULTS: A decision support tool that utilizes components of complete blood count and patient sex for prediction of SARS-CoV-2 PCR positivity demonstrated a C-statistic of 78 %, an optimized sensitivity of 93 %, and generalizability to other emergency department populations. By restricting PCR testing to predicted positive patients in a hypothetical scenario of 1000 patients requiring testing but testing resources limited to 60 % of patients, this tool would allow a 33 % increase in properly allocated resources. CONCLUSIONS: A prediction tool based on complete blood count results can better allocate SARS-CoV-2 testing and other health care resources such as personal protective equipment during a pandemic surge.


Subject(s)
Blood Cell Count/methods , Clinical Decision Rules , Coronavirus Infections/diagnosis , Diagnostic Tests, Routine/methods , Emergency Medical Services/methods , Pneumonia, Viral/diagnosis , Adult , Aged , Aged, 80 and over , COVID-19 , California , Case-Control Studies , Chicago , Female , Humans , Male , Middle Aged , Pandemics , Retrospective Studies , Sensitivity and Specificity , Washington , Young Adult
6.
Emerg Infect Dis ; 26(8): 1666-1670, 2020 Aug.
Article in English | MEDLINE | ID: covidwho-120058

ABSTRACT

We describe the epidemiology of a coronavirus disease (COVID-19) outbreak in a call center in South Korea. We obtained information on demographic characteristics by using standardized epidemiologic investigation forms. We performed descriptive analyses and reported the results as frequencies and proportions for categoric variables. Of 1,143 persons who were tested for COVID-19, a total of 97 (8.5%, 95% CI 7.0%-10.3%) had confirmed cases. Of these, 94 were working in an 11th-floor call center with 216 employees, translating to an attack rate of 43.5% (95% CI 36.9%-50.4%). The household secondary attack rate among symptomatic case-patients was 16.2% (95% CI 11.6%- 22.0%). Of the 97 persons with confirmed COVID-19, only 4 (1.9%) remained asymptomatic within 14 days of quarantine, and none of their household contacts acquired secondary infections. Extensive contact tracing, testing all contacts, and early quarantine blocked further transmission and might be effective for containing rapid outbreaks in crowded work settings.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Disease Outbreaks , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Betacoronavirus/genetics , COVID-19 , COVID-19 Testing , Call Centers , Clinical Laboratory Techniques/methods , Contact Tracing/statistics & numerical data , Coronavirus Infections/diagnosis , Family Characteristics , Female , Humans , Incidence , Male , Pandemics , Pneumonia, Viral/diagnosis , Quarantine/methods , Republic of Korea/epidemiology , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Severity of Illness Index
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