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1.
PLoS One ; 16(11): e0259097, 2021.
Article in English | MEDLINE | ID: covidwho-1575776

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a high risk of transmission in close-contact indoor settings, which may include households. Prior studies have found a wide range of household secondary attack rates and may contain biases due to simplifying assumptions about transmission variability and test accuracy. METHODS: We compiled serological SARS-CoV-2 antibody test data and prior SARS-CoV-2 test reporting from members of 9,224 Utah households. We paired these data with a probabilistic model of household importation and transmission. We calculated a maximum likelihood estimate of the importation probability, mean and variability of household transmission probability, and sensitivity and specificity of test data. Given our household transmission estimates, we estimated the threshold of non-household transmission required for epidemic growth in the population. RESULTS: We estimated that individuals in our study households had a 0.41% (95% CI 0.32%- 0.51%) chance of acquiring SARS-CoV-2 infection outside their household. Our household secondary attack rate estimate was 36% (27%- 48%), substantially higher than the crude estimate of 16% unadjusted for imperfect serological test specificity and other factors. We found evidence for high variability in individual transmissibility, with higher probability of no transmissions or many transmissions compared to standard models. With household transmission at our estimates, the average number of non-household transmissions per case must be kept below 0.41 (0.33-0.52) to avoid continued growth of the pandemic in Utah. CONCLUSIONS: Our findings suggest that crude estimates of household secondary attack rate based on serology data without accounting for false positive tests may underestimate the true average transmissibility, even when test specificity is high. Our finding of potential high variability (overdispersion) in transmissibility of infected individuals is consistent with characterizing SARS-CoV-2 transmission being largely driven by superspreading from a minority of infected individuals. Mitigation efforts targeting large households and other locations where many people congregate indoors might curb continued spread of the virus.


Subject(s)
COVID-19/epidemiology , COVID-19/transmission , Family Characteristics , Humans , Incidence , Likelihood Functions , Pandemics/statistics & numerical data , SARS-CoV-2/pathogenicity , Sensitivity and Specificity , Serologic Tests/methods , Utah/epidemiology
2.
Clin Transl Med ; 11(12): e668, 2021 12.
Article in English | MEDLINE | ID: covidwho-1568016

ABSTRACT

The level of postvaccine protection depends on two factors: antibodies and T-cell responses. While the first one is relatively easily measured, the measuring of the second one is a difficult problem. The recent studies indicate that the first one may be a good proxy for the protection, at least for SARS-CoV-2. The massive data currently gathered by both researcher and citizen scientists may be pivotal in confirming this observation, and the collective body of evidence is growing daily. This leads to an acceptance of IgG antibody levels as an accessible biomarker of individual's protection. With enormous and immediate need for assessing patient condition at the point of care, quantitative antibody analysis remains the most effective and efficient way to assess the protection against the disease. Let us not discount importance of reference points in the turmoil of current pandemics.


Subject(s)
Antibodies, Viral/chemistry , Antibodies/chemistry , Biomarkers/metabolism , COVID-19/blood , COVID-19/immunology , Antibody Specificity , Humans , Immune System , Immunity , Immunoglobulin G/metabolism , Intensive Care Units , Pandemics , Point-of-Care Systems , SARS-CoV-2 , Serologic Tests/methods , Serologic Tests/standards , Vaccines
3.
J Med Virol ; 93(12): 6794-6797, 2021 12.
Article in English | MEDLINE | ID: covidwho-1544304

ABSTRACT

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) has affected all inhabited continents, and India is currently experiencing a devastating second wave of coronavirus disease-2019 (COVID-19). Here, we examined the duration of clearance of SARS-CoV-2 in respiratory samples from 207 infected cases by real-time reverse-transcription polymerase chain reaction (RT-PCR). A substantial proportion of COVID-19 positive cases with cycle threshold (Ct) values more than or equal to 31 (45.7%) were subsequently tested negative for SARS-CoV-2 RNA within 7 days of initial detection of the viral load. A total of 60% of all the patients with COVID-19, irrespective of their Ct values, cleared SARS-CoV-2 RNA within 14 days of the initial detection. Longitudinal assessment of RT-PCR test results in individuals requiring 15-30 days to clear SARS-CoV-2 RNA showed a significant reduction of the viral load in samples with high or intermediate viral loads (Ct values ≤ 25 and between 26 and 30, respectively) but the follow-up group with low viral RNA (Ct values ≥ 31) exhibited a stable viral load. Together, these results suggest that COVID-19 positive cases with Ct values more than or equal to 31 require reduced duration to clear SARS-CoV-2, and thus, a shorter isolation period for this group might be considered to facilitate adequate space in the COVID Care Centres and reduce the burden on healthcare infrastructure.


Subject(s)
COVID-19/virology , SARS-CoV-2/genetics , Viral Load/genetics , Adult , Aged , COVID-19 Testing/methods , Diagnostic Tests, Routine/methods , Female , Humans , India , Longitudinal Studies , Male , Middle Aged , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Reverse Transcriptase Polymerase Chain Reaction/methods , Sensitivity and Specificity , Serologic Tests/methods , Young Adult
4.
Pan Afr Med J ; 38: 55, 2021.
Article in French | MEDLINE | ID: covidwho-1547713

ABSTRACT

The first outbreak of epidemic respiratory disease due to unknown etiology was reported in the Chinese city of Wuhan December 2019. The World Health Organization (WHO) firstly used the term "new coronavirus 2019" on December 29, 2019. This pandemic, which is currently called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a disease caused by SARS-CoV-2. It was subsequently called coronavirus disease 2019 (COVID-19) by the WHO. The purpose of this study was to determine the prevalence of antibodies against SARS-CoV-2 in all employees of the Nouakchott National Hospital Center (CHN). The study was conducted during the week 20/05/2020 to 27/05/2020. It involved 853 employees of all ranks (doctors, pharmacists, nurses, secretaries, security personnel, administrators...) of whom 504 were male and 331 were female, with a sex ratio of 1,52 with an average age of 39 years, ranging from 20 to 60 years. The screening for IgG and IgM antibodies to SARS-CoV-2 was performed using Biotime (Xiamen Biotime Biotechnology Co., Ltd.) immunochromatographic technique. Out of 835 employees included in our study, 14 were positive (1.67%) of whom 12 had IgM and IgG anti-SARS-CoV-2 antibodies and 2 had isolated IgM. Nasopharyngeal swab polymerase chain reaction (PCR) was performed in these 14 patients and was positive in six. While PCR is the gold standard for the diagnosis of SARS-CoV-2, serological tests for SARS-CoV-2 antibodies, in particular rapid tests (RDTs) are a diagnostic complement to COVID-19. They have the advantage of being easy to realize, of being safe both in the laboratories and outside the laboratories. RDTs enabled us to detect asymptomatic SARS-CoV-2 carriers within CHN employees. This allowed for patients management and isolation to protect patients and their environments.


Subject(s)
COVID-19 Testing , COVID-19/diagnosis , Health Personnel , SARS-CoV-2/isolation & purification , Adult , Antibodies, Viral/blood , COVID-19/epidemiology , Female , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Male , Mauritania/epidemiology , Middle Aged , Serologic Tests/methods , Young Adult
5.
BMC Cardiovasc Disord ; 21(1): 528, 2021 11 08.
Article in English | MEDLINE | ID: covidwho-1505900

ABSTRACT

BACKGROUND: The value of mechanical circulatory support (MCS) in cardiogenic shock, especially the combination of the ECMELLA approach (Impella combined with ECMO), remains controversial. CASE PRESENTATION: A previously healthy 33-year-old female patient was submitted to a local emergency department with a flu-like infection and febrile temperatures up to 39 °C. The patient was tested positive for type-A influenza, however negative for SARS-CoV-2. Despite escalated invasive ventilation, refractory hypercapnia (paCO2: 22 kPa) with severe respiratory acidosis (pH: 6.9) and a rising norepinephrine rate occurred within a few hours. Due to a Horovitz-Index < 100, out-of-centre veno-venous extracorporeal membrane oxygenation (vv-ECMO)-implantation was performed. A CT-scan done because of anisocoria revealed an extended dissection of the right vertebral artery. While the initial left ventricular function was normal, echocardiography revealed severe global hypokinesia. After angiographic exclusion of coronary artery stenoses, we geared up LV unloading by additional implantation of an Impella CP and expanded the vv-ECMO to a veno-venous-arterial ECMO (vva-ECMO). Clinically relevant bleeding from the punctured femoral arteries resulted in massive transfusion and was treated by vascular surgery later on. Under continued MCS, LVEF increased to approximately 40% 2 days after the initiation of ECMELLA. After weaning, the Impella CP was explanted at day 5 and the vva-ECMO was removed on day 9, respectively. The patient was discharged in an unaffected neurological condition to rehabilitation 25 days after the initial admission. CONCLUSIONS: This exceptional case exemplifies the importance of aggressive MCS in severe cardiogenic shock, which may be especially promising in younger patients with non-ischaemic cardiomyopathy and potentially reversible causes of cardiogenic shock. This case impressively demonstrates that especially young patients may achieve complete neurological restoration, even though the initial prognosis may appear unfavourable.


Subject(s)
Extracorporeal Membrane Oxygenation/methods , Heart-Assist Devices , Influenza A virus/isolation & purification , Influenza, Human , Respiration, Artificial/methods , Respiratory Insufficiency , Ventricular Dysfunction, Left , Adult , COVID-19/diagnosis , Clinical Deterioration , Critical Care/methods , Echocardiography/methods , Female , Heart Failure/physiopathology , Heart Failure/therapy , Humans , Influenza, Human/complications , Influenza, Human/diagnosis , Influenza, Human/physiopathology , Respiratory Insufficiency/etiology , Respiratory Insufficiency/physiopathology , Respiratory Insufficiency/therapy , SARS-CoV-2 , Serologic Tests/methods , Severity of Illness Index , Shock, Cardiogenic/etiology , Shock, Cardiogenic/physiopathology , Shock, Cardiogenic/therapy , Treatment Outcome , Ventricular Dysfunction, Left/etiology , Ventricular Dysfunction, Left/physiopathology , Ventricular Dysfunction, Left/therapy
6.
IEEE Rev Biomed Eng ; 14: 30-47, 2021.
Article in English | MEDLINE | ID: covidwho-1501335

ABSTRACT

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To counter COVID-19 spreading, an infrastructure to provide rapid and thorough molecular diagnostics and serology testing is the cornerstone of outbreak and pandemic management. We hereby review the clinical insights with regard to using molecular tests and immunoassays in the context of COVID-19 management life cycle: the preventive phase, the preparedness phase, the response phase and the recovery phase. The spatial and temporal distribution of viral RNA, antigens and antibodies during human infection is summarized to provide a biological foundation for accurate detection of the disease. We shared the lessons learned and the obstacles encountered during real world high-volume screening programs. Clinical needs are discussed to identify existing technology gaps in these tests. Leverage technologies, such as engineered polymerases, isothermal amplification, and direct amplification from complex matrices may improve the productivity of current infrastructure, while emerging technologies like CRISPR diagnostics, visual end point detection, and PCR free methods for nucleic acid sensing may lead to at-home tests. The lessons learned, and innovations spurred from the COVID-19 pandemic could upgrade our global public health infrastructure to better combat potential outbreaks in the future.


Subject(s)
COVID-19/diagnosis , COVID-19/immunology , Immunoassay/methods , Pathology, Molecular/methods , Animals , Humans , Life Cycle Stages , Pandemics/prevention & control , SARS-CoV-2/immunology , Serologic Tests/methods
8.
J Hepatol ; 75(2): 435-438, 2021 08.
Article in English | MEDLINE | ID: covidwho-1454287

ABSTRACT

BACKGROUND & AIMS: Two SARS-CoV-2 mRNA vaccines were approved to prevent COVID-19 infection, with reported vaccine efficacy of 95%. Liver transplant (LT) recipients are at risk of lower vaccine immunogenicity and were not included in the registration trials. We assessed vaccine immunogenicity and safety in this special population. METHODS: LT recipients followed at the Tel-Aviv Sourasky Medical Center and healthy volunteers were tested for SARS-CoV-2 IgG antibodies directed against the Spike-protein (S) and Nucleocapsid-protein (N) 10-20 days after receiving the second Pfizer-BioNTech BNT162b2 SARS-CoV-2 vaccine dose. Information regarding vaccine side effects and clinical data was collected from patients and medical records. RESULTS: Eighty LT recipients were enrolled. Mean age was 60 years and 30% were female. Twenty-five healthy volunteer controls were younger (mean age 52.7 years, p = 0.013) and mostly female (68%, p = 0.002). All participants were negative for IgG N-protein serology, indicating immunity did not result from prior COVID-19 infection. All controls were positive for IgG S-protein serology. Immunogenicity among LT recipients was significantly lower with positive serology in only 47.5% (p <0.001). Antibody titer was also significantly lower in this group (mean 95.41 AU/ml vs. 200.5 AU/ml in controls, p <0.001). Predictors for negative response among LT recipients were older age, lower estimated glomerular filtration rate, and treatment with high dose steroids and mycophenolate mofetil. No serious adverse events were reported in either group. CONCLUSION: LT recipients developed substantially lower immunological response to the Pfizer-BioNTech SARS-CoV-2 mRNA-based vaccine. Factors influencing serological antibody responses include age, renal function and immunosuppressive medications. The findings require re-evaluation of vaccine regimens in this population. LAY SUMMARY: The Pfizer-BioNTech BNT162b2 SARS-CoV-2 vaccine elicited substantially inferior immunity in liver transplant recipients. Less than half of the patients developed sufficient levels of antibodies against the virus, and in those who were positive, average antibody levels were 2x less compared to healthy controls. Factors predicting non-response were older age, renal function and immunosuppressive medications.


Subject(s)
Antibodies, Viral/blood , COVID-19 Vaccines , COVID-19 , Immunogenicity, Vaccine/immunology , Immunoglobulin G/blood , Immunosuppressive Agents/therapeutic use , Liver Transplantation/methods , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/immunology , Female , Humans , Israel/epidemiology , Kidney Function Tests , Male , Middle Aged , Risk Factors , SARS-CoV-2/immunology , Serologic Tests/methods , Serologic Tests/statistics & numerical data , Vaccination/adverse effects , Vaccination/methods
9.
Sci Rep ; 11(1): 18984, 2021 09 23.
Article in English | MEDLINE | ID: covidwho-1437691

ABSTRACT

Serological diagnostic of the severe respiratory distress syndrome coronavirus 2 (SARS-CoV-2) is a valuable tool for the determination of immunity and surveillance of exposure to the virus. In the context of an ongoing pandemic, it is essential to externally validate widely used tests to assure correct diagnostics and epidemiological estimations. We evaluated the performance of the COVID-19 ELISA IgG and the COVID-19 ELISA IgM/A (Vircell, S.L.) against a highly specific and sensitive in-house Luminex immunoassay in a set of samples from pregnant women and cord blood. The agreement between both assays was moderate to high for IgG but low for IgM/A. Considering seropositivity by either IgG and/or IgM/A, the technical performance of the ELISA was highly imbalanced, with 96% sensitivity at the expense of 22% specificity. As for the clinical performance, the negative predictive value reached 87% while the positive predictive value was 51%. Our results stress the need for highly specific and sensitive assays and external validation of diagnostic tests with different sets of samples to avoid the clinical, epidemiological and personal disturbances derived from serological misdiagnosis.


Subject(s)
COVID-19 Serological Testing/methods , Enzyme-Linked Immunosorbent Assay/methods , SARS-CoV-2/immunology , Antibodies, Viral/blood , COVID-19/diagnosis , COVID-19 Serological Testing/trends , Female , Fetal Blood/immunology , Humans , Immunoassay/methods , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Pandemics , Pregnancy , Sensitivity and Specificity , Serologic Tests/methods
10.
Int J Technol Assess Health Care ; 37(1): e87, 2021 Sep 22.
Article in English | MEDLINE | ID: covidwho-1434040

ABSTRACT

OBJECTIVE: In vitro diagnostic tests for SARS-COV-2, also known as serological tests, have rapidly spread. However, to date, mostly single-center technical and diagnostic performance's assessments have been carried out without an intralaboratory validation process and a health technology assessment (HTA) systematic approach. Therefore, the rapid HTA for evaluating antibody tests for SARS-COV-2 was applied. METHODS: The use of rapid HTA is an opportunity to test innovative technology. Unlike traditional HTA (which evaluates the benefits of new technologies after being tested in clinical trials or have been applied in practice for some time), the rapid HTA is performed during the early stages of developing new technology. A multidisciplinary team conducted the rapid HTA following the HTA Core Model® (version 3.0) developed by the European Network for Health Technology Assessment. RESULTS: The three methodological and analytical steps used in the HTA applied to the evaluation of antibody tests for SARS-COV-2 are reported: the selection of the tests to be evaluated; the research and collection of information to support the adoption and appropriateness of the technology; and the preparation of the final reports and their dissemination. Finally, the rapid HTA of serological tests for SARS-CoV-2 is summarized in a report that allows its dissemination and communication. CONCLUSIONS: The rapid-HTA evaluation method, in addition to highlighting the characteristics that differentiate the tests from each other, guarantees a timely and appropriate evaluation, becoming a tool to create a direct link between science and health management.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , COVID-19/immunology , Serologic Tests/methods , Humans , SARS-CoV-2 , Serologic Tests/standards , Technology Assessment, Biomedical , Time Factors
11.
Microbiol Spectr ; 9(2): e0045821, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1398599

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for a global pandemic with over 152 million cases and 3.19 million deaths reported by early May 2021. Understanding the serological response to SARS-CoV-2 is critical to determining the burden of infection and disease (coronavirus disease 2019 [COVID-19]) and transmission dynamics. We developed a capture IgM assay because it should have better sensitivity and specificity than the commonly used indirect assay. Here, we report the development and performance of a capture IgM enzyme-linked immunosorbent assay (ELISA) and a companion indirect IgG ELISA for the spike (S) and nucleocapsid (N) proteins and the receptor-binding domain (RBD) of S. We found that among the IgM ELISAs, the S ELISA was positive in 76% of 55 serum samples from SARS-CoV-2 PCR-positive patients, the RBD ELISA was positive in 55% of samples, and the N ELISA was positive in 15% of samples. The companion indirect IgG ELISAs were positive for S in 89% of the 55 serum samples, RBD in 78%, and N in 85%. While the specificities for IgM RBD, S, and N ELISAs and IgG S and RBD ELISAs were 97% to 100%, the specificity of the N IgG ELISA was lower (89%). RBD-specific IgM antibodies became undetectable by 3 to 6 months, and S IgM reached low levels at 6 months. The corresponding IgG S, RBD, and N antibodies persisted with some decreases in levels over this time period. These capture IgM ELISAs and the companion indirect IgG ELISAs should enhance serologic studies of SARS-CoV-2 infections. IMPORTANCE Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has inflicted tremendous loss of lives, overwhelmed health care systems, and disrupted all aspects of life worldwide since its emergence in Wuhan, China, in December 2019. Detecting current and past infection by PCR or serology is important to understanding and controlling SARS-CoV-2. With increasing prevalence of past infection or vaccination, IgG antibodies are less helpful in diagnosing a current infection. IgM antibodies indicate a more recent infection and can supplement PCR diagnosis. We report an alternative method, capture IgM, to detect serum IgM antibodies, which should be more sensitive and specific than most currently used methods. We describe this capture IgM assay and a companion indirect IgG assay for the SARS-CoV-2 spike (S), nucleocapsid (N), and receptor-binding domain (RBD) proteins. These assays can add value to diagnostic and serologic studies of coronavirus disease 2019 (COVID-19).


Subject(s)
Antibodies, Viral/immunology , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoglobulin M/blood , SARS-CoV-2/immunology , COVID-19/therapy , Coronavirus Nucleocapsid Proteins/immunology , Enzyme-Linked Immunosorbent Assay/methods , Humans , Immunization, Passive , Immunoglobulin G/blood , Phosphoproteins/immunology , Sensitivity and Specificity , Serologic Tests/methods , Spike Glycoprotein, Coronavirus/immunology
12.
Kidney Int ; 99(6): 1470-1477, 2021 06.
Article in English | MEDLINE | ID: covidwho-1386157

ABSTRACT

Patients with end stage kidney disease receiving in-center hemodialysis (ICHD) have had high rates of SARS-CoV-2 infection. Following infection, patients receiving ICHD frequently develop circulating antibodies to SARS-CoV-2, even with asymptomatic infection. Here, we investigated the durability and functionality of the immune responses to SARS-CoV-2 infection in patients receiving ICHD. Three hundred and fifty-six such patients were longitudinally screened for SARS-CoV-2 antibodies and underwent routine PCR-testing for symptomatic and asymptomatic infection. Patients were regularly screened for nucleocapsid protein (anti-NP) and receptor binding domain (anti-RBD) antibodies, and those who became seronegative at six months were screened for SARS-CoV-2 specific T-cell responses. One hundred and twenty-nine (36.2%) patients had detectable antibody to anti-NP at time zero, of whom 127 also had detectable anti-RBD. Significantly, at six months, 71/111 (64.0%) and 99/116 (85.3%) remained anti-NP and anti-RBD seropositive, respectively. For patients who retained antibody, both anti-NP and anti-RBD levels were reduced significantly after six months. Eleven patients who were anti-NP seropositive at time zero, had no detectable antibody at six months; of whom eight were found to have SARS-CoV-2 antigen specific T cell responses. Independent of antibody status at six months, patients with baseline positive SARS-CoV-2 serology were significantly less likely to have PCR confirmed infection over the following six months. Thus, patients receiving ICHD mount durable immune responses six months post SARS-CoV-2 infection, with fewer than 3% of patients showing no evidence of humoral or cellular immunity.


Subject(s)
Antibodies, Viral/analysis , COVID-19/immunology , Kidney Failure, Chronic/therapy , Renal Dialysis/adverse effects , SARS-CoV-2/immunology , COVID-19 Testing , Female , Humans , Immunity , Male , Pandemics , Polymerase Chain Reaction , Reinfection , SARS-CoV-2/isolation & purification , Serologic Tests/methods
14.
J Infect Dis ; 224(4): 595-605, 2021 08 16.
Article in English | MEDLINE | ID: covidwho-1367024

ABSTRACT

BACKGROUND: Convalescent plasma containing neutralizing antibody to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is under investigation for coronavirus disease 2019 (COVID-19) treatment. We report diverse virological characteristics of UK intensive care patients enrolled in the Immunoglobulin Domain of the REMAP-CAP randomized controlled trial that potentially influence treatment outcomes. METHODS: SARS-CoV-2 RNA in nasopharyngeal swabs collected pretreatment was quantified by PCR. Antibody status was determined by spike-protein ELISA. B.1.1.7 was differentiated from other SARS-CoV-2 strains using allele-specific probes or restriction site polymorphism (SfcI) targeting D1118H. RESULTS: Of 1274 subjects, 90% were PCR positive with viral loads 118-1.7 × 1011IU/mL. Median viral loads were 40-fold higher in those IgG seronegative (n = 354; 28%) compared to seropositives (n = 939; 72%). Frequencies of B.1.1.7 increased from <1% in November 2020 to 82% of subjects in January 2021. Seronegative individuals with wild-type SARS-CoV-2 had significantly higher viral loads than seropositives (medians 5.8 × 106 and 2.0 × 105 IU/mL, respectively; P = 2 × 10-15). CONCLUSIONS: High viral loads in seropositive B.1.1.7-infected subjects and resistance to seroconversion indicate less effective clearance by innate and adaptive immune responses. SARS-CoV-2 strain, viral loads, and antibody status define subgroups for analysis of treatment efficacy.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , COVID-19/therapy , SARS-CoV-2/immunology , Viral Load/immunology , Aged , Antibodies, Neutralizing/immunology , COVID-19/virology , Critical Illness , Female , Humans , Immunization, Passive , Immunoglobulin G/immunology , Male , Middle Aged , RNA, Viral/immunology , Serologic Tests/methods , Spike Glycoprotein, Coronavirus/immunology , United Kingdom
16.
Med Princ Pract ; 30(4): 385-394, 2021.
Article in English | MEDLINE | ID: covidwho-1354613

ABSTRACT

OBJECTIVE: To assess the diagnostic performance of lateral flow immunochromatographic assays (LFAs) of 4 different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG, or total), comparing them with the nucleic acid amplification test (NAAT) or the clinical defined test (definite or probable SARS-CoV-2 infection, respectively). METHODS: One hundred nineteen serum samples were randomly selected by convenience and distributed in the following groups: (1) group with SARS-CoV-2 infection (n = 82; RT-qPCR positive [definite, n = 70] and probable [n = 12]); (2) other diseases (n = 27; other viruses identified [n = 8] and SARS of other etiologies [n = 19]); and (3) healthy control group (n = 10). LFAs of 4 manufacturers were compared: MedTest Coronavirus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and 1-Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co., China). RESULTS: The 4 tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95% CI: 77.26-93.11%), specificity (100%; 90.51-100%), DOR (257; 60-1,008), LR+ (33.43; 4.82-231.85), LR- (0.13; 0.08-0.23), accuracy (90.76%; 84.06-95.29%), and Matthews correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values. CONCLUSION: Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the different kits. LFA tests cannot replace molecular diagnostics but should be used as an additional screening tool.


Subject(s)
Antibodies, Viral/blood , COVID-19 Testing/methods , Serologic Tests/methods , Brazil/epidemiology , Case-Control Studies , Female , Humans , Immunoassay/methods , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Nucleic Acid Amplification Techniques , Pandemics , SARS-CoV-2 , Sensitivity and Specificity
17.
Clin Chem Lab Med ; 59(11): 1878-1884, 2021 10 26.
Article in English | MEDLINE | ID: covidwho-1341521

ABSTRACT

OBJECTIVES: Numerous analytical systems, rapidly made available on the market throughout the SARS-CoV-2 pandemic, aim to detect COVID-19, and to continuously update and improve the same systems. Medical laboratory professionals have also developed in-house analytical procedures in order to satisfy the enormous volume of requests for tests. These developments have highlighted the need control the analytical procedures used in order to guarantee patient safety. The External Quality Assessment (EQA) Scheme, an important quality assurance tool, aims to guarantee high standard performance for laboratory and analytical procedures. The aim of the present study was to report on the results collected in an experimental EQA scheme for the serological diagnosis of SARS-CoV-2. METHODS: All qualitative results collected in the different EQA surveys were summarized in order to identify the percentage of laboratory results in relation to typology of antibodies, results and samples. RESULTS: A total of 4,867 data sets were collected. The analysis of EQA data made, demonstrates a better agreement among laboratories results for total Ig than single immunoglobulins (IgG, IgM, IgA) in the case samples positive for SARS-CoV-2, and a wide divergence between IgM results for positive samples (only 34.9% were correct). Results for negative controls and specificity controls demonstrated a better overall agreement than results for positive samples. CONCLUSIONS: Working in collaboration with the IVD manufacturers, laboratory professionals must strive to achieve harmonization of results, and to develop well-defined protocols complying with the ISO 15189 requirements.


Subject(s)
Antibodies, Viral/immunology , COVID-19/diagnosis , SARS-CoV-2/immunology , Serologic Tests/methods , Antibodies, Viral/blood , COVID-19/immunology , Humans , Immunoglobulin A/blood , Immunoglobulin A/metabolism , Immunoglobulin G/blood , Immunoglobulin G/metabolism , Immunoglobulin M/blood , Immunoglobulin M/metabolism , Pilot Projects , Quality Assurance, Health Care , Retrospective Studies , Sensitivity and Specificity , Severity of Illness Index
18.
PLoS One ; 16(7): e0255412, 2021.
Article in English | MEDLINE | ID: covidwho-1332014

ABSTRACT

A second wave of COVID-19 has demonstrated how challenging it will be to achieve sustained control of the disease, even with vaccination underway in many countries. Therefore, it remains relevant to keep improving our understanding of the distribution of COVID-19, especially of asymptomatic individuals, among different populations, and particularly in vulnerable regions. Hence, this population-based serosurvey had the objective of estimating the prevalence of individuals 18 years of age or older infected by SARS-CoV-2, and the proportion of asymptomatic individuals, among a vulnerable population living in an urban setting. This was a cross-sectional single-stage cluster sampling serosurvey conducted between September and December of 2019, in a vulnerable region of the city of São Paulo, Brazil. Families covered by three public primary healthcare units represented the selected clusters. After study inclusion, participants were asked about signs and symptoms related to COVID-19, and had collected 10 mL of blood for serology testing. A total of 272 individuals from 185 families were included in the study, out of the 400 eligible individuals for inclusion, resulting in a non-response rate of 32%. The post stratified prevalence of individuals infected by SARS-CoV-2 was 45.2% (95% CI: 39.4-51.0%), with a proportion of asymptomatic cases of 30.2% (95% CI: 23.3-38.0%). This population-based serosurvey identified a greater prevalence of infected individuals by SARS-CoV-2 compared to data from the beginning of the pandemic, and from a recent citywide serosurvey, with a similar proportion of asymptomatic individuals. It demonstrated the value of primary healthcare services for disease surveillance activities, and the importance of more focused serosurveys, especially in vulnerable locations, and the need to evaluate new surveillance strategies to take into account asymptomatic cases.


Subject(s)
Antibodies, Viral/blood , COVID-19/blood , COVID-19/epidemiology , Adult , Aged , Asymptomatic Infections/epidemiology , Brazil/epidemiology , Cities/epidemiology , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Pandemics/prevention & control , Prevalence , Seroepidemiologic Studies , Serologic Tests/methods , Surveys and Questionnaires
19.
Nat Commun ; 12(1): 4383, 2021 07 19.
Article in English | MEDLINE | ID: covidwho-1317806

ABSTRACT

In February and March 2020, two mass swab testing campaigns were conducted in Vo', Italy. In May 2020, we tested 86% of the Vo' population with three immuno-assays detecting antibodies against the spike and nucleocapsid antigens, a neutralisation assay and Polymerase Chain Reaction (PCR). Subjects testing positive to PCR in February/March or a serological assay in May were tested again in November. Here we report on the results of the analysis of the May and November surveys. We estimate a seroprevalence of 3.5% (95% Credible Interval (CrI): 2.8-4.3%) in May. In November, 98.8% (95% Confidence Interval (CI): 93.7-100.0%) of sera which tested positive in May still reacted against at least one antigen; 18.6% (95% CI: 11.0-28.5%) showed an increase of antibody or neutralisation reactivity from May. Analysis of the serostatus of the members of 1,118 households indicates a 26.0% (95% CrI: 17.2-36.9%) Susceptible-Infectious Transmission Probability. Contact tracing had limited impact on epidemic suppression.


Subject(s)
Antibodies, Viral/immunology , COVID-19 Testing/methods , COVID-19/immunology , COVID-19/transmission , SARS-CoV-2/immunology , Serologic Tests/methods , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19 Nucleic Acid Testing , Contact Tracing , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Italy/epidemiology , Male , Nucleocapsid , Seroepidemiologic Studies , Spike Glycoprotein, Coronavirus/immunology
20.
J Med Virol ; 93(12): 6794-6797, 2021 12.
Article in English | MEDLINE | ID: covidwho-1310533

ABSTRACT

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) has affected all inhabited continents, and India is currently experiencing a devastating second wave of coronavirus disease-2019 (COVID-19). Here, we examined the duration of clearance of SARS-CoV-2 in respiratory samples from 207 infected cases by real-time reverse-transcription polymerase chain reaction (RT-PCR). A substantial proportion of COVID-19 positive cases with cycle threshold (Ct) values more than or equal to 31 (45.7%) were subsequently tested negative for SARS-CoV-2 RNA within 7 days of initial detection of the viral load. A total of 60% of all the patients with COVID-19, irrespective of their Ct values, cleared SARS-CoV-2 RNA within 14 days of the initial detection. Longitudinal assessment of RT-PCR test results in individuals requiring 15-30 days to clear SARS-CoV-2 RNA showed a significant reduction of the viral load in samples with high or intermediate viral loads (Ct values ≤ 25 and between 26 and 30, respectively) but the follow-up group with low viral RNA (Ct values ≥ 31) exhibited a stable viral load. Together, these results suggest that COVID-19 positive cases with Ct values more than or equal to 31 require reduced duration to clear SARS-CoV-2, and thus, a shorter isolation period for this group might be considered to facilitate adequate space in the COVID Care Centres and reduce the burden on healthcare infrastructure.


Subject(s)
COVID-19/virology , SARS-CoV-2/genetics , Viral Load/genetics , Adult , Aged , COVID-19 Testing/methods , Diagnostic Tests, Routine/methods , Female , Humans , India , Longitudinal Studies , Male , Middle Aged , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Reverse Transcriptase Polymerase Chain Reaction/methods , Sensitivity and Specificity , Serologic Tests/methods , Young Adult
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