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1.
J Clin Microbiol ; : JCM0171721, 2021 Oct 20.
Article in English | MEDLINE | ID: covidwho-1639280

ABSTRACT

Background: We aimed to assess the specificity of SARS-CoV-2 antibody detection assays among people with tissue-borne parasitic infections. Methods: We tested three SARS-CoV-2 antibody-detection assays [cPass SARS-CoV-2 Neutralization Antibody Detection Kit (cPass), Abbott SARS-CoV-2 IgG assay (Abbott Architect), and STANDARD Q COVID-19 IgM/IgG Combo Rapid Test ("SD RDT IgM"/"SD RDT IgG")] among 559 pre-COVID-19 seropositive sera for several parasitic infections. Results: The specificity of assays was 95-98% overall. However, lower specificity was observed among sera from patients with protozoan infections of the reticuloendothelial system, such as human African trypanosomiasis (Abbott Architect; 88% [95%CI 75-95]), visceral leishmaniasis (SD RDT IgG; 80% [95%CI 30-99]), and from patients with recent malaria from a holoendemic area of Senegal (ranging from 91% for Abbott Architect and SD RDT IgM to 98-99% for cPass and SD RDT IgG). For specimens from patients with evidence of past or present helminth infection overall, test specificity estimates were all ≥ 96%. Sera collected from patients clinically suspected of parasitic infections that tested negative for these infections yielded a specificity of 98-100%. The majority (>85%) of false-positive results were positive by only one assay. Conclusions: The specificity of SARS-CoV-2 serological assays among sera from patients with tissue-borne parasitic infections was below the threshold required for decisions about individual patient care. Specificity is markedly increased by the use of confirmatory testing with a second assay. Finally, the SD RDT IgG proved similarly specific to laboratory-based assays and provides an option in low-resource settings when detection of anti-SARS-CoV-2 IgG is indicated.

2.
PLoS One ; 16(12): e0261003, 2021.
Article in English | MEDLINE | ID: covidwho-1556871

ABSTRACT

The true severity of infection due to COVID-19 is under-represented because it is based on only those who are tested. Although nucleic acid amplifications tests (NAAT) are the gold standard for COVID-19 diagnostic testing, serological assays provide better population-level SARS-CoV-2 prevalence estimates. Implementing large sero-surveys present several logistical challenges within Canada due its unique geography including rural and remote communities. Dried blood spot (DBS) sampling is a practical solution but comparative performance data on SARS-CoV-2 serological tests using DBS is currently lacking. Here we present test performance data from a well-characterized SARS-CoV-2 DBS panel sent to laboratories across Canada representing 10 commercial and 2 in-house developed tests for SARS-CoV-2 antibodies. Three commercial assays identified all positive and negative DBS correctly corresponding to a sensitivity, specificity, positive predictive value, and negative predictive value of 100% (95% CI = 72.2, 100). Two in-house assays also performed equally well. In contrast, several commercial assays could not achieve a sensitivity greater than 40% or a negative predictive value greater than 60%. Our findings represent the foundation for future validation studies on DBS specimens that will play a central role in strengthening Canada's public health policy in response to COVID-19.

3.
Ann Intern Med ; 174(2): 287-288, 2021 02.
Article in English | MEDLINE | ID: covidwho-1526981
4.
J Clin Microbiol ; : JCM0171721, 2021 Oct 20.
Article in English | MEDLINE | ID: covidwho-1476385

ABSTRACT

Background: We aimed to assess the specificity of SARS-CoV-2 antibody detection assays among people with tissue-borne parasitic infections. Methods: We tested three SARS-CoV-2 antibody-detection assays [cPass SARS-CoV-2 Neutralization Antibody Detection Kit (cPass), Abbott SARS-CoV-2 IgG assay (Abbott Architect), and STANDARD Q COVID-19 IgM/IgG Combo Rapid Test ("SD RDT IgM"/"SD RDT IgG")] among 559 pre-COVID-19 seropositive sera for several parasitic infections. Results: The specificity of assays was 95-98% overall. However, lower specificity was observed among sera from patients with protozoan infections of the reticuloendothelial system, such as human African trypanosomiasis (Abbott Architect; 88% [95%CI 75-95]), visceral leishmaniasis (SD RDT IgG; 80% [95%CI 30-99]), and from patients with recent malaria from a holoendemic area of Senegal (ranging from 91% for Abbott Architect and SD RDT IgM to 98-99% for cPass and SD RDT IgG). For specimens from patients with evidence of past or present helminth infection overall, test specificity estimates were all ≥ 96%. Sera collected from patients clinically suspected of parasitic infections that tested negative for these infections yielded a specificity of 98-100%. The majority (>85%) of false-positive results were positive by only one assay. Conclusions: The specificity of SARS-CoV-2 serological assays among sera from patients with tissue-borne parasitic infections was below the threshold required for decisions about individual patient care. Specificity is markedly increased by the use of confirmatory testing with a second assay. Finally, the SD RDT IgG proved similarly specific to laboratory-based assays and provides an option in low-resource settings when detection of anti-SARS-CoV-2 IgG is indicated.

5.
PLoS One ; 16(6): e0252617, 2021.
Article in English | MEDLINE | ID: covidwho-1280619

ABSTRACT

BACKGROUND: Many studies report the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. We aimed to synthesize seroprevalence data to better estimate the level and distribution of SARS-CoV-2 infection, identify high-risk groups, and inform public health decision making. METHODS: In this systematic review and meta-analysis, we searched publication databases, preprint servers, and grey literature sources for seroepidemiological study reports, from January 1, 2020 to December 31, 2020. We included studies that reported a sample size, study date, location, and seroprevalence estimate. We corrected estimates for imperfect test accuracy with Bayesian measurement error models, conducted meta-analysis to identify demographic differences in the prevalence of SARS-CoV-2 antibodies, and meta-regression to identify study-level factors associated with seroprevalence. We compared region-specific seroprevalence data to confirmed cumulative incidence. PROSPERO: CRD42020183634. RESULTS: We identified 968 seroprevalence studies including 9.3 million participants in 74 countries. There were 472 studies (49%) at low or moderate risk of bias. Seroprevalence was low in the general population (median 4.5%, IQR 2.4-8.4%); however, it varied widely in specific populations from low (0.6% perinatal) to high (59% persons in assisted living and long-term care facilities). Median seroprevalence also varied by Global Burden of Disease region, from 0.6% in Southeast Asia, East Asia and Oceania to 19.5% in Sub-Saharan Africa (p<0.001). National studies had lower seroprevalence estimates than regional and local studies (p<0.001). Compared to Caucasian persons, Black persons (prevalence ratio [RR] 3.37, 95% CI 2.64-4.29), Asian persons (RR 2.47, 95% CI 1.96-3.11), Indigenous persons (RR 5.47, 95% CI 1.01-32.6), and multi-racial persons (RR 1.89, 95% CI 1.60-2.24) were more likely to be seropositive. Seroprevalence was higher among people ages 18-64 compared to 65 and over (RR 1.27, 95% CI 1.11-1.45). Health care workers in contact with infected persons had a 2.10 times (95% CI 1.28-3.44) higher risk compared to health care workers without known contact. There was no difference in seroprevalence between sex groups. Seroprevalence estimates from national studies were a median 18.1 times (IQR 5.9-38.7) higher than the corresponding SARS-CoV-2 cumulative incidence, but there was large variation between Global Burden of Disease regions from 6.7 in South Asia to 602.5 in Sub-Saharan Africa. Notable methodological limitations of serosurveys included absent reporting of test information, no statistical correction for demographics or test sensitivity and specificity, use of non-probability sampling and use of non-representative sample frames. DISCUSSION: Most of the population remains susceptible to SARS-CoV-2 infection. Public health measures must be improved to protect disproportionately affected groups, including racial and ethnic minorities, until vaccine-derived herd immunity is achieved. Improvements in serosurvey design and reporting are needed for ongoing monitoring of infection prevalence and the pandemic response.


Subject(s)
Antibodies, Viral/blood , COVID-19/epidemiology , Adolescent , Adult , Aged , COVID-19 Serological Testing , Child , Health Personnel/statistics & numerical data , Humans , Incidence , Middle Aged , Sensitivity and Specificity , Seroepidemiologic Studies , Young Adult
6.
Open Forum Infect Dis ; 8(6): ofab220, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1276208

ABSTRACT

Background: Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) surrogate neutralization assays that obviate the need for viral culture offer substantial advantages regarding throughput and cost. The cPass SARS-CoV-2 Neutralization Antibody Detection Kit (GenScript) is the first such commercially available assay that detects antibodies that block receptor-binding domain (RBD)/angiotensin-converting enzyme (ACE)-2 interaction. We aimed to evaluate cPass to inform its use and assess its added value compared with anti-RBD enzyme-linked immunosorbent assays (ELISAs). Methods: Serum reference panels comprising 205 specimens were used to compare cPass to plaque-reduction neutralization test (PRNT) and a pseudotyped lentiviral neutralization (PLV) assay for detection of neutralizing antibodies. We assessed the correlation of cPass with an ELISA detecting anti-RBD immunoglobulin (Ig)G, IgM, and IgA antibodies at a single timepoint and across intervals from onset of symptoms of SARS-CoV-2 infection. Results: Compared with PRNT-50, cPass sensitivity ranged from 77% to 100% and specificity was 95% to 100%. Sensitivity was also high compared with the pseudotyped lentiviral neutralization assay (93%; 95% confidence interval [CI], 85-97), but specificity was lower (58%; 95% CI, 48-67). Highest agreement between cPass and ELISA was for anti-RBD IgG (r = 0.823). Against the pseudotyped lentiviral neutralization assay, anti-RBD IgG sensitivity (99%; 95% CI, 94-100) was very similar to that of cPass, but overall specificity was lower (37%; 95% CI, 28-47). Against PRNT-50, results of cPass and anti-RBD IgG were nearly identical. Conclusions: The added value of cPass compared with an IgG anti-RBD ELISA was modest.

7.
Ann Intern Med ; 173(6): 450-460, 2020 09 15.
Article in English | MEDLINE | ID: covidwho-937708

ABSTRACT

Accurate serologic tests to detect host antibodies to severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) will be critical for the public health response to the coronavirus disease 2019 pandemic. Many use cases are envisaged, including complementing molecular methods for diagnosis of active disease and estimating immunity for individuals. At the population level, carefully designed seroepidemiologic studies will aid in the characterization of transmission dynamics and refinement of disease burden estimates and will provide insight into the kinetics of humoral immunity. Yet, despite an explosion in the number and availability of serologic assays to test for antibodies against SARS-CoV-2, most have undergone minimal external validation to date. This hinders assay selection and implementation, as well as interpretation of study results. In addition, critical knowledge gaps remain regarding serologic correlates of protection from infection or disease, and the degree to which these assays cross-react with antibodies against related coronaviruses. This article discusses key use cases for SARS-CoV-2 antibody detection tests and their application to serologic studies, reviews currently available assays, highlights key areas of ongoing research, and proposes potential strategies for test implementation.


Subject(s)
Betacoronavirus/immunology , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Pneumonia, Viral/diagnosis , Pneumonia, Viral/immunology , Serologic Tests/methods , COVID-19 , COVID-19 Testing , Humans , Pandemics , SARS-CoV-2 , Seroepidemiologic Studies
8.
Ann Intern Med ; 172(11): 726-734, 2020 06 02.
Article in English | MEDLINE | ID: covidwho-52648

ABSTRACT

Diagnostic testing to identify persons infected with severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infection is central to control the global pandemic of COVID-19 that began in late 2019. In a few countries, the use of diagnostic testing on a massive scale has been a cornerstone of successful containment strategies. In contrast, the United States, hampered by limited testing capacity, has prioritized testing for specific groups of persons. Real-time reverse transcriptase polymerase chain reaction-based assays performed in a laboratory on respiratory specimens are the reference standard for COVID-19 diagnostics. However, point-of-care technologies and serologic immunoassays are rapidly emerging. Although excellent tools exist for the diagnosis of symptomatic patients in well-equipped laboratories, important gaps remain in screening asymptomatic persons in the incubation phase, as well as in the accurate determination of live viral shedding during convalescence to inform decisions to end isolation. Many affluent countries have encountered challenges in test delivery and specimen collection that have inhibited rapid increases in testing capacity. These challenges may be even greater in low-resource settings. Urgent clinical and public health needs currently drive an unprecedented global effort to increase testing capacity for SARS-CoV-2 infection. Here, the authors review the current array of tests for SARS-CoV-2, highlight gaps in current diagnostic capacity, and propose potential solutions.


Subject(s)
Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Betacoronavirus , Biomarkers/blood , COVID-19 , COVID-19 Testing , COVID-19 Vaccines , Clinical Laboratory Techniques , Humans , Pandemics , Point-of-Care Testing , Radiography, Thoracic , Real-Time Polymerase Chain Reaction , SARS-CoV-2 , Serologic Tests , Specimen Handling/methods
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