Seven-Month Analysis of Five SARS-CoV-2 Antibody Assay Results after ChAdOx1 nCoV-19 Vaccination: Significant Decrease in SARS-CoV-2 Antibody Titer

We investigated the longevity rates of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after a complete ChAdOx1 nCoV-19 vaccination, which are rare and important to estimate their efficacy and establish a vaccination strategy. We assessed the positivity rates and changes of titers before (T0) and at one month (T1), four months (T2), and seven months (T3) after a ChAdOx1 nCoV-19 vaccination using five SARS-CoV-2 antibody assays. A total of 874 serum samples were obtained from 228 (T0 and T1), 218 (T2), and 200 (T3) healthcare workers. The positive rates for all five assays were 0.0–0.9% at T0, 66.2–92.5% at T1, 98.2–100.0% at T2, and 66.0–100.0% at T3. The positive rates at T3 were decreased compared to those at T2. The median antibody titers of all the assays at T3 were significantly decreased compared to those at T2 (860.5 to 232.0 U/mL for Roche total, 1041.5 to 325.5 AU/mL for Abbott IgG, 10.9 to 2.3 index for Siemens IgG, 99.5% to 94.7% for SD Biosensor V1, and 88.5% to 38.2% for GenScript). A third-dose scheme can be considered based on our data generated from five representative assays. Our findings contribute insights into SARS-CoV-2 antibody assays and appropriate vaccination strategies.

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Persistence of Antibodies Against Spike Glycoprotein of SARS-CoV-2 in Healthcare Workers Post Double Dose of BBV-152 and AZD1222 Vaccines

Frontiers in Medicine ◽

10.3389/fmed.2021.778129 ◽

2021 ◽

Vol 8 ◽

Author(s):

Hari Ram Choudhary ◽

Debaprasad Parai ◽

Girish Chandra Dash ◽

Jaya Singh Kshatri ◽

Narayan Mishra ◽

...

Keyword(s):

Antibody Titer ◽

Healthcare Workers ◽

Igg Antibodies ◽

Serum Samples ◽

History Of ◽

Antibody Titers ◽

Chemiluminescent Microparticle Immunoassay ◽

Research Facilities

Purpose: We investigated the persistence of the vaccine-induced immunoglobulin G (IgG) antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among healthcare workers (HCWs) in Odisha who received a complete dose of either Covaxin or Covishield vaccine.Methods: This 24-week longitudinal cohort study was conducted from January to July 2021 with participants from 6 healthcare and research facilities of Odisha to understand the dynamicity of the vaccine-induced IgG antibodies against SARS-CoV-2 after the complete dose of vaccines.Results: Serum samples were collected from 614 participants during each follow-up and were tested in two chemiluminescent microparticle immunoassay (CLIA)-based platforms to detect SARS-CoV-2 antibodies both qualitatively and quantitatively. Among these participants, 308 (50.2%) participants were Covishield recipients and the rest 306 (49.8%) participants took Covaxin. A total of 81 breakthrough cases were recorded and the rest 533 HCWs without any history of postvaccination infection showed significant antibody waning either from T3 (Covaxin recipient) or T4 (Covishield recipient). The production of vaccine-induced IgG antibodies is significantly higher (p < 0.001) in Covishield compared with Covaxin. Covishield recipients produced higher median anti-S IgG titer than Covaxin. No statistically significant differences in antibody titers were observed based on age, gender, comorbidities, and blood groups.Conclusion: This 6-month follow-up study documents a 2-fold and 4-fold decrease in spike antibody titer among Covishield and Covaxin recipients, respectively. The clinical implications of antibody waning after vaccination are not well understood. It also highlights the need for further data to understand the long-term persistence of vaccine-induced antibody and threshold antibody titer required for protection against reinfection.

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Vaccination strategy and anti - SARS-CoV-2 S titers in healthcare workers of the INT – IRCCS “Fondazione Pascale” Cancer Center (Naples, Italy)

Infectious Agents and Cancer ◽

10.1186/s13027-021-00375-2 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Ernesta Cavalcanti ◽

Maria Antonietta Isgrò ◽

Domenica Rea ◽

Lucia Di Capua ◽

Giusy Trillò ◽

...

Keyword(s):

Immune Response ◽

Immune Responses ◽

Healthcare Workers ◽

Geometric Mean ◽

Vaccination Strategy ◽

Antibody Responses ◽

Cancer Center ◽

Serum Samples ◽

Humoral Immune ◽

History Of

Abstract Background Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and the resulting disease, coronavirus disease 2019 (COVID-19), have spread to millions of people globally, requiring the development of billions of different vaccine doses. The SARS-CoV-2 spike mRNA vaccine (named BNT162b2/Pfizer), authorized by the FDA, has shown high efficacy in preventing SARS-CoV-2 infection after administration of two doses in individuals 16 years of age and older. In the present study, we retrospectively evaluated the differences in the SARS-CoV-2 humoral immune response after vaccine administration in the two different cohorts of workers at the INT - IRCCS “Fondazione Pascale” Cancer Center (Naples, Italy): previously infected to SARS-CoV-2 subjects and not infected to SARS-CoV-2 subjects. Methods We determined specific anti-RBD (receptor-binding domain) titers against trimeric spike glycoprotein (S) of SARS-CoV-2 by Roche Elecsys Anti-SARS-CoV-2 S immunoassay in serum samples of 35 healthcare workers with a previous documented history of SARS-CoV-2 infection and 158 healthcare workers without, after 1 and 2 doses of vaccine, respectively. Moreover, geometric mean titers and relative fold changes (FC) were calculated. Results Both previously infected and not infected to SARS-CoV-2 subjects developed significant immune responses to SARS-CoV-2 after the administration of 1 and 2 doses of vaccine, respectively. Anti-S antibody responses to the first dose of vaccine were significantly higher in previously SARS-CoV-2-infected subjects in comparison to titers of not infected subjects after the first as well as the second dose of vaccine. Fold changes for subjects previously infected to SARS-CoV-2 was very modest, given the high basal antibody titer, as well as the upper limit of 2500.0 BAU/mL imposed by the Roche methods. Conversely, for naïve subjects, mean fold change following the first dose was low ($$ \overline{x} $$ x ¯ =1.6), reaching 3.8 FC in 72 subjects (45.6%) following the second dose. Conclusions The results showed that, as early as the first dose, SARS-CoV-2-infected individuals developed a remarkable and statistically significant immune response in comparison to those who did not contract the virus previously, suggesting the possibility of administering only one dose in previously SARS-CoV-2-infected subjects. FC for previously infected subjects should not be taken into account for the generally high pre-vaccination values. Conversely, FC for not infected subjects, after the second dose, were = 3.8 in > 45.0% of vaccinees, and ≤ 3.1 in 19.0%, the latter showing a potential susceptibility to further SARS-CoV-2 infection.

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An Anti-Nucleocapsid Antigen Sars-Cov-2 Total Antibody Assay Finds Comparable Results in Edta-Anticoagulated Whole Blood Obtained from Capillary and Venous Blood Sampling

Data ◽

10.3390/data5040105 ◽

2020 ◽

Vol 5 (4) ◽

pp. 105

Author(s):

Martin Risch ◽

Marc Kovac ◽

Corina Risch ◽

Dorothea Hillmann ◽

Michael Ritzler ◽

...

Keyword(s):

Whole Blood ◽

Venous Blood ◽

Capillary Blood ◽

Blood Sampling ◽

Attractive Alternative ◽

Antibody Assay ◽

Antibody Assays ◽

Antibody Titers ◽

Antibody Levels ◽

Venous Blood Sampling

Although SARS-CoV-2 antibody assays have been found to provide valid results in EDTA-anticoagulated whole blood, so far, they have not demonstrated that antibody levels in whole blood originating from capillary blood samples are comparable to antibody levels measured in blood from a venous origin. Here, blood is drawn simultaneously by capillary and venous blood sampling. Antibody titers are determined by an assay employing electrochemiluminescence (ECLIA) and SARS-CoV-2 total immunoglobulins are detected with specificity directed against the nucleocapsid antigen. Six individuals with confirmed COVID-19 and six individuals without COVID-19 are analyzed. Antibody titers in capillary venous whole blood did not show significant differences, and when corrected for hematocrit, they did not differ from the results obtained from serum. In conclusion, capillary sampled EDTA-anticoagulated whole blood seems to be an attractive alternative matrix for the evaluation of SARS-CoV-2 antibodies when employing ECLIA for detecting total antibodies directed against nucleocapsid antibodies.

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Validation of a new automated chemiluminescent anti-SARS-CoV-2 IgM and IgG antibody assay system detecting both N and S proteins in Japan

10.1101/2020.07.16.20155796 ◽

2020 ◽

Author(s):

RIn Yokoyama ◽

Makoto Kurano ◽

Yoshifumi Morita ◽

Takuya Shimura ◽

Yuki Nakano ◽

...

Keyword(s):

Measurement System ◽

False Positive ◽

Laboratory Testing ◽

Antibody Test ◽

Measurement Range ◽

Antibody Assay ◽

Serum Samples ◽

Igg Antibody ◽

Antibody Titers ◽

Pcr Test

PCR methods are presently the standard for the diagnosis of Coronavirus disease 2019 (COVID-19), but additional methodologies are needed to complement PCR methods, which have some limitations. Here, we validated and investigated the usefulness of measuring serum antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using the iFlash3000 CLIA analyzer. We measured IgM and IgG titers against SARS-CoV-2 in sera collected from 26 PCR-positive COVID-19 patients, 53 COVID-19-suspected but PCR-negative patients, and 20 and 100 randomly selected non-COVID-19 patients who visited our hospital in 2020 and 2017, respectively. The within-day and between-day precisions were regarded as good, since the coefficient variations were below 5%. Linearity was also considered good between 0.6 AU/mL and 112.7 AU/mL for SARS-CoV-2 IgM and between 3.2 AU/mL and 55.3 AU/mL for SARS-CoV-2 IgG, while the linearity curves plateaued above the upper measurement range. We also confirmed that the seroconversion and no-antibody titers were over the cutoff values in all 100 serum samples collected in 2017. These results indicate that this measurement system successfully detects SARS-CoV-2 IgM/IgG. We observed four false-positive cases in the IgM assay and no false-positive cases in the IgG assay when 111 serum samples known to contain autoantibodies were evaluated. The concordance rates of the antibody test with the PCR test were 98.1% for SARS-CoV-2 IgM and 100% for IgG among PCR-negative cases and 30.8% for SARS-CoV-2 IgM and 73.1% for SARS-CoV-2 IgG among PCR-positive cases. In conclusion, the performance of this measurement system is sufficient for use in laboratory testing.

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Immunological features that determine the strength of antibody responses to BNT162b2 mRNA vaccine against SARS-CoV-2

10.1101/2021.06.21.449182 ◽

2021 ◽

Author(s):

Takahiro Kageyama ◽

Shigeru Tanaka ◽

Keishi Etori ◽

Koto Hattori ◽

Kazusa Miyachi ◽

...

Keyword(s):

T Cells ◽

Antibody Titer ◽

Cd8 T Cells ◽

Healthcare Workers ◽

Mononuclear Cells ◽

Antibody Responses ◽

Peripheral Blood Mononuclear ◽

Transitional B Cells ◽

Blood Mononuclear Cells ◽

Antibody Titers

We analyzed peripheral blood mononuclear cells (PBMCs) of each 20 individuals with a high anti-SARS-CoV-2 antibody titer and a low antibody titer out of 1,774 healthcare workers who received BNT162b2 mRNA vaccine. A higher antibody titer was associated with the frequencies of naive and transitional B cells before vaccination. In addition, fold changes in the frequency of activated CD8+ T cells upon vaccination were correlated with the antibody titers.

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Estimating SARS-CoV-2 Spike Antibody Levels Among Sputnik V First Dose Vaccinated People in Pakistan: Formulation of Anti-COVID-19 National Mass Vaccination Strategy.

10.21203/rs.3.rs-502338/v1 ◽

2021 ◽

Author(s):

Umar Saeed ◽

Sara Rizwan Uppal ◽

Zahra Zahid Piracha ◽

Aftab Ahmad Khan ◽

Azhar Rasheed ◽

...

Keyword(s):

Antibody Titer ◽

Previous History ◽

Vaccination Strategy ◽

Cross Sectional Study ◽

Mass Vaccination ◽

Spike Protein ◽

Cross Sectional ◽

Diagnostic Center ◽

Antibody Titers ◽

Antibody Levels

Abstract Rapid ramp up of immune responses against SARS-CoV-2 during pandemic enables adequate prevention and treatment for COVID-19. Estimating levels of SARS-CoV-2 spike protein antibodies post vaccination is crucial for designing mass-vaccination strategies. The aim of this study was to evaluate effectiveness of Sputnik V first dose in Pakistan. A cross-sectional study of 2000 participants was conducted for examining Gam-COVID-Vac or Sputnik V first dose effects at 21st days post administration at Islamabad Diagnostic Center, Islamabad, Pakistan. From 100 real-time PCR negative (SARS-CoV-2 RNA) individuals, samples were collected and analyzed for antibodies to the SARS-CoV-2 spike protein using Electro-chemiluminescence immunoassay (ECLIA) (Elecsys # 09289267190 Roche, USA). 85% of the participants showed strong positive results with SARS-CoV-2 spike protein antibodies >1.5 AU/ml. The individuals with antibody titer >250 AU/ml were 34.9%. Among those with antibody levels >250 AU/ml 52% had previous history of COVID-19 infection. While participants with >100 AU/ml of antibodies were 12.7%. However 9.5% showed antibody titer of >25 AU/ml. 27% of participants had antibody titers of >1.5-2.5 AU/ml. While antibody titers of <1.5 AU/ml were observed among 15.9% of participants. Majority of the individuals represented significantly high antibody titers against SARS-CoV-2 even before second booster dose of Ad5 based Sputnik V vaccine. Continuous monitoring of antibody levels among COVID-19 vaccinated populations are deemed to assess humoral immunity status against SARS-CoV-2 infections.

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Analysis of antibody assay methods and classes of viral antibodies in serodiagnosis of cytomegalovirus infection

Journal of Clinical Microbiology ◽

10.1128/jcm.8.2.153-159.1978 ◽

1978 ◽

Vol 8 (2) ◽

pp. 153-159 ◽

Cited By ~ 1

Author(s):

N E Cremer ◽

M Hoffman ◽

E H Lennette

Keyword(s):

Antibody Titer ◽

Complement Fixation ◽

Gradient Centrifugation ◽

Immunoglobulin M ◽

Serum Specimen ◽

Antibody Assay ◽

Indirect Hemagglutination ◽

Antibody Titers ◽

Apparent Reason ◽

Assay Methods

Forty-nine serum pairs with antibody to cytomegalovirus (CMV) were evaluated for rises in antibody titer (greater than or equal to fourfold) by indirect hemagglutination (IHA) and complement fixation (CF), using a freeze-thaw antigen (FT) and a glycine extract antigen (GE). In this sample CF-FT detected more rises in antibody titer than did CF-GE. IHA detected the least number. The apparent reason for stationary antibody titers with CF-GE and IHA was the presence of high antibody titers in the first serum specimen. Separation of immunoglobulin classes of 20 serum pairs by sucrose gradient centrifugation indicated that these antibodies with IHA were of the immunoglobulin M (IgM) class and those with CF-GE were of the IgG class. By separation of immunoglobulin classes, rises in IgG CMV antibody titers were seen with IHA, rises not observed in the whole serum because of high IgM antibody titers in the first serum specimen. Absence of rises in antibody titers with CF-FT was due in part to too early sampling of the second serum specimen (less than 21 days) and in part to an apparent inability of some individuals to respond with antibody reactive with FT antigen. CF-GE and CF-FT antibodies of the IgM class were detected in some sera, usually in specimens collected more than 10 days after the onset of symptoms. Although reactive with CMV antigen, the specificity of these IgM antibodies in relation to rheumatoid factor requires clarification.

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COMPARISON OF PERFORMANCE CHARACTERISTICS BETWEEN LATERAL FLOW, ELISA AND ELECTROCHEMILUMINESCENCE IMMUNOASSAYS FOR THE DETECTION OF SARS-COV-2 ANTIBODIES AMONG HEALTHCARE WORKERS

10.1101/2021.04.29.21256260 ◽

2021 ◽

Author(s):

M R Shincy ◽

Vandana Govindan ◽

H H Sudhakar ◽

V T Venkatesha ◽

K Padmapriya ◽

...

Keyword(s):

Severe Acute Respiratory Syndrome ◽

Healthcare Workers ◽

Care Pathway ◽

Point Of Care ◽

Lateral Flow ◽

Central Research ◽

Serum Samples ◽

Igg Antibody ◽

Human Igg ◽

Serological Tests

ABSTRACTBackgroundMedical professionals and researchers have been urging the need for wide and rapid testing of citizens in order to plan measures that can contain the spread of the virus. Antibody tests play an important role throughout the patient care pathway and are vital for the management and surveillance of the virus. Although RT-PCR is considered as the gold standard, serological tests based on antibodies are helpful for on-time detection. We performed one to one assessment of point-of-care lateral flow assay (POCTs), enzyme immunoassay (EIAs), electrochemiluminescence immunoassay (CLIA), to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibody.Materials and Methods611 healthcare workers were recruited between November and December 2020 at Central Research Laboratory, KIMS. Collected serum samples were analysed according to manufacturer’s protocol. The Standard Q IgG/IgM combo assay, Anti-SARS CoV-2 Human IgG ELISA, and the Elecsys® to measure the IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).ResultsThe kits displayed a sensitivity of 61.2%,79.5%, 91.8% and specificity of 61.7%,64.1%,80.2% for the Standard Q IgG/IgM combo assay, Anti-SARS CoV-2 Human IgG ELISA, and the Elecsys® in order.ConclusionOur results indicate high sensitivity and specificity for the Elecsys® assay compared to Anti-SARS CoV-2 Human IgG ELISA, the Standard Q IgG/IgM combo assay.

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COMPARISON OF PERFORMANCE CHARACTERISTICS BETWEEN LATERAL FLOW, ELISAAND ELECTROCHEMILUMINESCENCE IMMUNOASSAYS FOR THE DETECTION OF SARS-COV-2 ANTIBODIES AMONG HEALTHCARE WORKERS

10.36106/ijsr/0101617 ◽

2021 ◽

pp. 45-48

Author(s):

Shincy M R ◽

Vandana Govindan ◽

Sudhakar H H ◽

Padmapriya K ◽

Venkatesha V T ◽

...

Keyword(s):

Severe Acute Respiratory Syndrome ◽

Healthcare Workers ◽

Care Pathway ◽

Point Of Care ◽

High Sensitivity ◽

Central Research ◽

Serum Samples ◽

Igg Antibody ◽

Human Igg ◽

Serological Tests

Background: The detection of SARS-CoV-2 IgG is important to determine the course of COVID-19. Medical professionals and researchers have been urging the need for wide and rapid testing of citizens in order to plan measures that can contain the spread of the virus. Antibody tests play an important role throughout the patient care pathway and are vital for the management and surveillance of the virus. Although RTPCR is considered to be the gold standard, serological tests based on antibodies could be very helpful for on-time detection. We performed one to one assessment of electrochemiluminescence immunoassay, enzyme immunoassay (EIAs), and point-of-care lateral ow assay (POCTs) to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibody. Materials and Methods: 611 healthcare workers were recruited between November and December 2020 at Central Research Laboratory, KIMS. ® Collected serum samples were analysed using three commercially available assays: the Elecsys , Anti-SARS CoV-2 Human IgG ELISA, the Standard Q IgG/IgM combo assay following the manufacturer's protocol to measure the IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results:The kits displayed a sensitivity of 91.8%, 79.5% ,61.2% and a specicity of 80.2%, 64.1% ,61.7% in order. Conclusion: ® Our results indicate a high sensitivity and specicity for the Elecsys assay compared to Anti-SARS CoV-2 Human IgG ELISA, the Standard Q IgG/IgM combo assays.

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Validation of a new automated chemiluminescent anti-SARS-CoV-2 IgM and IgG antibody assay system detecting both N and S proteins in Japan

PLoS ONE ◽

10.1371/journal.pone.0247711 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0247711

Author(s):

Rin Yokoyama ◽

Makoto Kurano ◽

Yoshifumi Morita ◽

Takuya Shimura ◽

Yuki Nakano ◽

...

Keyword(s):

False Positive ◽

Antibody Test ◽

Measurement Range ◽

Antibody Assay ◽

Serum Samples ◽

Igg Antibody ◽

Automated Method ◽

Antibody Titers ◽

Pcr Test ◽

S Proteins

PCR methods are presently the standard for the diagnosis of Coronavirus disease 2019 (COVID-19), but additional methodologies are needed to complement PCR methods, which have some limitations. Here, we validated and investigated the usefulness of measuring serum antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using the iFlash3000 CLIA analyzer. We measured IgM and IgG titers against SARS-CoV-2 in sera collected from 26 PCR-positive COVID-19 patients, 53 COVID-19-suspected but PCR-negative patients, and 20 and 100 randomly selected non-COVID-19 patients who visited our hospital in 2020 and 2017, respectively. The repeatability and within-laboratory precision were obviously good in validations, following to the CLSI document EP15-A3. Linearity was also considered good between 0.6 AU/mL and 112.7 AU/mL for SARS-CoV-2 IgM and between 3.2 AU/mL and 55.3 AU/mL for SARS-CoV-2 IgG, while the linearity curves plateaued above the upper measurement range. We also confirmed that the seroconversion and no-antibody titers were over the cutoff values in all 100 serum samples collected in 2017. These results indicate that this measurement system successfully detects SARS-CoV-2 IgM/IgG. We observed four false-positive cases in the IgM assay and no false-positive cases in the IgG assay when 111 serum samples known to contain autoantibodies were evaluated. The concordance rates of the antibody test with the PCR test were 98.1% for SARS-CoV-2 IgM and 100% for IgG among PCR-negative cases and 30.8% for SARS-CoV-2 IgM and 73.1% for SARS-CoV-2 IgG among PCR-positive cases. In conclusion, the performance of this new automated method for detecting antibody against both N and S proteins of SARS-CoV-2 is sufficient for use in laboratory testing.

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