scholarly journals Importation Risk Stratification for COVID19 using Quantitative Serology

2021 ◽  
Author(s):  
David E Williams
Keyword(s):  
Risk Stratification ◽  
Quantitative Measurement ◽  
Nature Medicine ◽  
Antibody Concentration ◽  
Present Communication ◽  
Breakthrough Infection ◽  
Igg Antibody ◽  
Previous Infection ◽  
Time Required ◽  
Importation Risk

AbstractRecent work (Khoury et al.,Nature Medicine2021, 27 (7), 1205-1211) has shown that measurement of IgG antibody concentration in blood correlates well with vaccine efficacy. The present communication builds on this work and considers the probability of infection given immunity, taking into account the distribution across the population of antibody concentration in vaccinated or convalescent people. The model is consistent with the observed rates of breakthrough infection following vaccination or previous infection. The model is then developed to consider the use of quantitative measurement of antibody concentration on arrival as an aid to risk stratification of travellers. The model indicates that such a measurement could significantly decrease the quarantine time required to achieve a given level of importation risk.

scholarly journals Über die automatische Registrierung der Hämolyse durch Serumkomplement und Lysolecithin

1965 ◽  
Vol 20 (6) ◽  
pp. 569-574 ◽  
Author(s):  
H. G. Siedentopf ◽  
K. Lauenstein ◽  
H. Fischer
Keyword(s):  
Optical Density ◽  
Quantitative Measurement ◽  
Kinetic Studies ◽  
Quantitative Comparison ◽  
Lytic Activity ◽  
Antibody Concentration ◽  
Serum Complement ◽  
Serum Dilution ◽  
Set Up ◽  
Time Required

An experimental set up is described in which the degree of optical density during lysis of sensitized sheep erythrocytes by complement (C′) and other hemolytic agents is followed photometrically and recorded automatically.The time required for 50% reduction in optical density is inversely proportional to the serum dilution and thus can be taken for quantitative measurement of C′-activity. The linear relationship forms the basis for a quantitative comparison of the effect of various inhibitors. A definite advantage of the method is due to the ease with which kinetic studies of whole complement and the intermediate steps of its action can be performed.Using this method the influence of variations of the quantity of red cells, of antibody concentration, and of temperature are reported.To demonstrate the usefulness of the method a number of experiments are given, each of which is characteristic for a certain field of application. They include estimation of lytic activity of serum complement, comparison of different C′ inhibitors, action of C′ on tanned erythrocytes in the absence of antibody, estimation of lytic activity of lysolecithin (LL), hemolysis by LL as obtained by activation of C′ in serum and from erythrocytes lysed by C′, inhibition of C′ and of LL by albumin and by lecithin.

scholarly journals Immune complexes containing factor V in a patient with an acquired neutralizing antibody

Blood ◽  
1985 ◽  
Vol 65 (4) ◽  
pp. 810-818 ◽  
Author(s):  
HC Chiu ◽  
AK Rao ◽  
C Beckett ◽  
RW Colman
Keyword(s):  
Immunosorbent Assay ◽  
Immune Complexes ◽  
Neutralizing Antibody ◽  
Circulating Immune Complexes ◽  
Heat Inactivation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Concentration ◽  
Factor V ◽  
Igg Antibody ◽  
Plasma Factor

Abstract An 82-year-old woman presented with extensive hematomas and melena associated with markedly decreased plasma factor V coagulant activity (FV:C). Using a competitive enzyme-linked immunosorbent assay developed in our laboratory, we made serial measurements of factor V antigen (FV:Ag) in plasma and found it to be normal or elevated. The patient's plasma was demonstrated to contain an IgG antibody that could neutralize FV:C in normal plasma. The antibody was of restricted heterogeneity (IgG1, IgG2,kappa). Circulating immune complexes containing antibody to factor V and FV:Ag were demonstrated directly in the plasma by immunoelectrophoresis with polyclonal monospecific antibody and with a monoclonal antibody using an enzyme-linked immunosorbent assay. Presence of neutralizing antibody could be demonstrated in vitro even at times when FV:C was within normal limits by heat inactivation of FV:C. Treatment with plasma and platelet transfusions as well as plasmapheresis induced definite but transient elevation of FV:C. Steroid therapy lowered the neutralizing antibody concentration and produced a rapid and persistent elevation of FV:C during two separate hospitalizations. This report describes a patient in whom levels of FV:Ag have been serially measured, and the presence of circulating immune complexes consisting of factor V and a neutralizing antibody have been directly demonstrated.

scholarly journals The burden of parvovirus B19 infection in women of childbearing age in England and Wales

2007 ◽  
Vol 135 (8) ◽  
pp. 1354-1362 ◽  
Author(s):  
A. J. VYSE ◽  
N. J. ANDREWS ◽  
L. M. HESKETH ◽  
R. PEBODY
Keyword(s):  
Parvovirus B19 ◽  
Childbearing Age ◽  
Igg Antibody ◽  
England And Wales ◽  
Force Of Infection ◽  
Previous Infection ◽  
Parvovirus B19 Infection ◽  
Specific Igg ◽  
Age Range ◽  
Made In

SUMMARYA serological survey has been used to investigate the epidemiology of parvovirus B19 infection in England and Wales. A total of 2835 sera representing the complete age range were selected from a convenience collection obtained in 1996 that reflects the general population and screened for parvovirus B19-specific IgG. Antibody prevalence rose nonlinearly with age from 21% in those aged 1–4 years to >75% in adults aged ⩾45 years. Force-of-infection estimates were similar to those previously made in 1991, being highest in those aged <15 years. There was no association between evidence of previous infection and sex or region. Quantitatively strongest antibody responses were found in those aged 15–34 years and IgG levels in females were 28·5% higher than those found in males (P=0·004, 95% CI 8·2–52·6). Applying the upper 95% confidence interval for the force of infection to maternity estimates for England and Wales in 1996, parvovirus infection in pregnancy was estimated to occur on average in up to 1 in every 512 pregnancies each year. This represents 1257 maternal infections, causing up to an estimated 59 fetal deaths and 11 cases of hydrops fetalis annually. An analysis of all available laboratory-confirmed parvovirus infections found a mean of 944 infections per year in women aged 15–44 years highlighting a need for enhanced surveillance of maternal parvovirus B19 infection in England and Wales, including information on both pregnancy and outcome of pregnancy.

scholarly journals Antibody Response after BNT162b2 Vaccination in Healthcare Workers Previously Exposed and Not Exposed to SARS-CoV-2

2021 ◽  
Vol 10 (18) ◽  
pp. 4204
Author(s):  
Marcello Salvaggio ◽  
Federica Fusina ◽  
Filippo Albani ◽  
Maurizio Salvaggio ◽  
Rasula Beschi ◽  
...  
Keyword(s):  
Antibody Response ◽  
Healthcare Workers ◽  
Antibody Concentration ◽  
Clinical Documentation ◽  
Receptor Binding Domain ◽  
Effective Number ◽  
Significant Difference ◽  
Before And After ◽  
Previous Infection ◽  
Antibody Levels

The Pfizer/BioNtech Comirnaty vaccine (BNT162b2 mRNA COVID-19) against SARS-CoV-2 is currently in use in Italy. Antibodies to evaluate SARS-CoV-2 infection prior to administration are not routinely tested; therefore, two doses may be administered to asymptomatic previously exposed subjects. The aim of this study is to assess if any difference in antibody concentration between subjects exposed and not exposed to SARS-CoV-2 prior to BNT162b2 was present after the first dose and after the second dose of vaccine. Data were retrospectively collected from the clinical documentation of 337 healthcare workers who underwent SARS-CoV-2 testing before and after BNT162b2. Total anti RBD (receptor-binding domain) antibodies against SARS-CoV-2′s spike protein were measured before and 21 days after the first dose, and 12 days after the second dose of BNT162b2. Twenty-one days after the first dose, there was a statistically significant difference in antibody concentration between the two groups, which was also maintained twelve days after the second dose. In conclusion, antibody response after receiving BNT162b2 is greater in subjects who have been previously exposed to SARS-CoV-2 than in subjects who have not been previously exposed to the virus, both after 21 days after the first dose and after 12 days from the second dose. Antibody levels, 21 days after the first dose, reached a titer considered positive by the test manufacturer in the majority of subjects who have been previously infected with SARS-CoV-2. Evaluating previous infection prior to vaccination in order to give the least effective number of doses should be considered.

scholarly journals COVID 19 breakthrough infection risk: a simple physical model describing the dependence on antibody concentration

2021 ◽  
Author(s):  
David E Williams
Keyword(s):  
Vaccine Efficacy ◽  
Infection Risk ◽  
Antibody Concentration ◽  
Receptor Binding Domain ◽  
Breakthrough Infection ◽  
Virus Surface ◽  
Domain Antibody ◽  
Simple Physical Model ◽  
Rational Explanation ◽  
Spike Proteins

Abstract The empirically-observed dependence on blood IgG anti-receptor binding domain antibody concentration of SARS-CoV-2 vaccine efficacy against infection has a rational explanation in the statistics of binding of antibody to spike proteins on the virus surface: namely that the probability of protection is the probability of antibody binding to more than a critical number of the spike proteins protruding from the virus. The model is consistent with the observed antibody concentrations required to induce immunity and with the observed dependence of vaccine efficacy on antibody concentration and thus is a useful tool in the development of models to relate, for an individual person, risk of breakthrough infection given measured antibody concentration

scholarly journals Clinical Characteristics of Recurrent-positive Coronavirus Disease 2019 after Curative Discharge: a retrospective analysis of 15 cases in Wuhan China

2020 ◽  
Author(s):  
Lan Chen ◽  
Zhen-Yu Zhang ◽  
Xiao-Bin Zhang ◽  
Su-Zhen Zhang ◽  
Qiu-Ying Han ◽  
...  
Keyword(s):  
Length Of Stay ◽  
Clinical Characteristics ◽  
Control Group ◽  
Rt Pcr ◽  
Igg Antibody ◽  
Post Discharge ◽  
Positive Group ◽  
Virus Rna ◽  
Time Required ◽  
Antibody Levels

In China, the patients with previously negative RT-PCR results again test positive during the post-discharge isolation period. We aimed to determine the clinical characteristics of these recurrent-positive patients. We retrospectively reviewed the data of 15 recurrent-positive patients and 107 control patients with non-recurrent, moderate COVID-19 treated in Wuhan, China. Clinical data and laboratory results were comparatively analyzed. We found that recurrent-positive patients had moderate disease. The rate of recurrent-positive disease in our hospital was 1.87%. Recurrent-positive patients were significantly younger (43(35-54) years) than control patients (60(43-69) years) (P=0.011). The early LOS (length of stay in hospital before recurrence) was significantly longer in recurrent-positive patients (36(34-45) days) than in control patients (15(7-30) days) (P =0.001). The time required for the first conversion of RT-PCR results from positive to negative was significantly longer in recurrent-positive patients (14(10-17) days) than in control patients (6(3-9) days) (P =0.011). Serum COVID-19 antibody levels were significantly lower in recurrent-positive patients than in control patients (IgM: 13.69 ± 4.38 vs. 68.10 ± 20.85 AU/mL, P = 0.015; IgG: 78.53 ± 9.30 vs. 147.85 ± 13.33 AU/mL, P < 0.0001). Recurrent-positive patients were younger than control patients. The early LOS (length of stay in hospital before recurrence) was significantly longer in recurrent-positive group than that in control group. COVID-19 IgM/IgG antibody levels were significantly lower in recurrent-positive group than those in control group, which might explain why the virus RNA RT-PCR was positive after the initial clinical cure(with three times of virus RNA RT-PCR negative). The virus might not be fully eliminated because of the lower IgG level and their later replicating might result in recurrent-positive virus RNA RT-PCR.

scholarly journals Comparison of Capture Immunoglobulin M (IgM) and IgG Enzyme-Linked Immunosorbent Assay (ELISA) and Nonstructural Protein NS1 Serotype-Specific IgG ELISA for Differentiation of Primary and Secondary Dengue Virus Infections

2003 ◽  
Vol 10 (4) ◽  
pp. 622-630 ◽  
Author(s):  
Pei-Yun Shu ◽  
Li-Kuang Chen ◽  
Shu-Fen Chang ◽  
Yi-Yun Yueh ◽  
Ling Chow ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Immunosorbent Assay ◽  
Primary Infection ◽  
Nonstructural Protein ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Infections ◽  
Igg Antibody ◽  
Previous Infection ◽  
Specific Igg

ABSTRACT We have found that NS1 serotype-specific immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) can be used to differentiate primary and secondary dengue virus infections. This is due to the fact that the NS1-specific IgG antibody cannot be detected before day 9 of illness for primary infection, so the NS1-specific IgG antibodies measured in acute-phase sera must come from previous infection. Comparison of NS1 serotype-specific IgG ELISA with envelope- and membrane-specific capture IgM and IgG ELISA in the differentiation of primary and secondary dengue virus infections showed good correlation (95.90% agreement). Most important, we have found that the serotype of the dengue virus from the majority of patients with primary infection could be correctly identified when convalescent-phase or postinfection sera were analyzed by NS1 serotype-specific IgG ELISA. These findings suggested that NS1 serotype-specific IgG ELISA could be reliably applied for serodiagnosis and seroepidemiological study of dengue virus infection.

Thrombocytopenia caused by the development of antibodies to thrombopoietin

Blood ◽  
2001 ◽  
Vol 98 (12) ◽  
pp. 3241-3248 ◽  
Author(s):  
Junzhi Li ◽  
Chun Yang ◽  
Yuping Xia ◽  
Amy Bertino ◽  
John Glaspy ◽  
...  
Keyword(s):  
Platelet Count ◽  
Growth And Development ◽  
Marked Reduction ◽  
Apparent Molecular Weight ◽  
Bone Marrow Examination ◽  
Antibody Concentration ◽  
Severe Thrombocytopenia ◽  
Igg Antibody ◽  
Development Factor ◽  
Bleeding Episodes

Abstract Thrombocytopenia developed in some individuals treated with a recombinant thrombopoietin (TPO), pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF). Three of the subjects who developed severe thrombocytopenia were analyzed in detail to determine the cause of their thrombocytopenia. Except for easy bruising and heavy menses, none of these subjects had major bleeding episodes; none responded to intravenous immunoglobulin or prednisone. Bone marrow examination revealed a marked reduction in megakaryocytes. All 3 thrombocytopenic subjects had antibody to PEG-rHuMGDF that cross-reacted with endogenous TPO and neutralized its biological activity. All anti-TPO antibodies were immunoglobulin G (IgG), with increased amounts of IgG4; no IgM antibodies to TPO were detected at any time. A quantitative assay for IgG antibody to TPO was developed and showed that the antibody concentration varied inversely with the platelet count. Anti-TPO antibody recognized epitopes located in the first 163 amino acids of TPO and prevented TPO from binding to its receptor. In 2 subjects, endogenous TPO levels were elevated, but the TPO circulated as a biologically inactive immune complex with anti-TPO IgG; the endogenous TPO in these complexes had an apparent molecular weight of 95 000, slightly larger than the full-length recombinant TPO. None of the subjects had atypical HLA or platelet antigens, and the TPO cDNA was normal in both that were sequenced. Treatment of one subject with cyclosporine eliminated the antibody and normalized the platelet count. These data demonstrate a new mechanism for thrombocytopenia in which antibody develops to TPO; because endogenous TPO is produced constitutively, thrombocytopenia ensues.

scholarly journals Large-Scale Study of Antibody Titer Decay following BNT162b2 mRNA Vaccine or SARS-CoV-2 Infection

Vaccines ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Ariel Israel ◽  
Yotam Shenhar ◽  
Ilan Green ◽  
Eugene Merzon ◽  
Avivit Golan-Cohen ◽  
...  
Keyword(s):  
Large Scale ◽  
Immune Protection ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Exponential Decrease ◽  
Previous Infection ◽  
History Of ◽  
Antibody Titers ◽  
Antibody Levels ◽  
Kinetics Of

Immune protection following either vaccination or infection with SARS-CoV-2 is thought to decrease over time. We designed a retrospective study, conducted at Leumit Health Services in Israel, to determine the kinetics of SARS-CoV-2 IgG antibodies following administration of two doses of BNT162b2 vaccine, or SARS-CoV-2 infection in unvaccinated individuals. Antibody titers were measured between 31 January 2021, and 31 July 2021 in two mutually exclusive groups: (i) vaccinated individuals who received two doses of BNT162b2 vaccine and had no history of previous infection with COVID-19 and (ii) SARS-CoV-2 convalescents who had not received the vaccine. A total of 2653 individuals fully vaccinated by two doses of vaccine during the study period and 4361 convalescent patients were included. Higher SARS-CoV-2 IgG antibody titers were observed in vaccinated individuals (median 1581 AU/mL IQR [533.8–5644.6]) after the second vaccination than in convalescent individuals (median 355.3 AU/mL IQR [141.2–998.7]; p < 0.001). In vaccinated subjects, antibody titers decreased by up to 38% each subsequent month while in convalescents they decreased by less than 5% per month. Six months after BNT162b2 vaccination 16.1% subjects had antibody levels below the seropositivity threshold of <50 AU/mL, while only 10.8% of convalescent patients were below <50 AU/mL threshold after 9 months from SARS-CoV-2 infection. This study demonstrates individuals who received the Pfizer-BioNTech mRNA vaccine have different kinetics of antibody levels compared to patients who had been infected with the SARS-CoV-2 virus, with higher initial levels but a much faster exponential decrease in the first group.

scholarly journals SARS-CoV-2 vaccine breakthrough infection following a previous infection in a healthcare worker

2021 ◽  
Author(s):  
Aayush Gupta ◽  
Rahul C. Bhoyar ◽  
Shahzad Mirza ◽  
Bani Jolly ◽  
Vigneshwar Senthivel ◽  
...  
Keyword(s):  
Healthcare Worker ◽  
Breakthrough Infection ◽  
Previous Infection
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