Roche Elecsys Research Articles

The representative COVID-19 cohort Munich (KoCo19): from the beginning of the pandemic to the Delta virus variant

BackgroundPopulation-based serological studies allow to estimate prevalence of SARS-CoV-2 infections despite a substantial number of mild or asymptomatic disease courses. This became even more relevant for decision making after vaccination started. The KoCo19 cohort tracks the pandemic progress in the Munich general population for over two years, setting it apart in Europe.MethodsRecruitment occurred during the initial pandemic wave, including 5313 participants above 13 years from private households in Munich. Four follow-ups were held at crucial times of the pandemic, with response rates of at least 70%. Participants filled questionnaires on socio-demographics and potential risk factors of infection. From Follow-up 2, information on SARS-CoV-2 vaccination was added. SARS-CoV-2 antibody status was measured using the Roche Elecsys® Anti-SARS-CoV-2 anti-N assay (indicating previous infection) and the Roche Elecsys® Anti-SARS-CoV-2 anti-S assay (indicating previous infection and/or vaccination). This allowed us to distinguish between sources of acquired antibodies.ResultsThe SARS-CoV-2 estimated cumulative sero-prevalence increased from 1.6% (1.1-2.1%) in May 2020 to 14.5% (12.7-16.2%) in November 2021. Underreporting with respect to official numbers fluctuated with testing policies and capacities, becoming a factor of more than two during the second half of 2021. Simultaneously, the vaccination campaign against the SARS-CoV-2 virus increased the percentage of the Munich population having antibodies, with 86.8% (85.5-87.9%) having developed anti-S and/or anti-N in November 2021. Incidence rates for infections after (BTI) and without previous vaccination (INS) differed (ratio INS/BTI of 2.1, 0.7-3.6). However, the prevalence of infections was higher in the non-vaccinated population than in the vaccinated one. Considering the whole follow-up time, being born outside Germany, working in a high-risk job and living area per inhabitant were identified as risk factors for infection, while other socio-demographic and health-related variables were not. Although we obtained significant within-household clustering of SARS-CoV-2 cases, no further geospatial clustering was found.ConclusionsVaccination increased the coverage of the Munich population presenting SARS-CoV-2 antibodies, but breakthrough infections contribute to community spread. As underreporting stays relevant over time, infections can go undetected, so non-pharmaceutical measures are crucial, particularly for highly contagious strains like Omicron.

Serum cortisol assay performance following the 1mg overnight dexamethasone suppression test.

The 1mg overnight dexamethasone suppression test (ONDST) is recommended for the differential diagnosis of Cushing's syndrome and the investigation of adrenal incidentalomas. Despite documented variation in serum cortisol immunoassay performance, little has been published regarding its effect on the ONDST. Assess the performance of three immunoassay platforms (Roche Elecsys II, Abbott Alinity & Siemens Centaur) when compared to a liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Samples (n = 77) sent to the laboratory as part of an ONDST were retrieved prior to disposal, anonymized, and analysed on all platforms. Samples with factors impacting immunoassay analysis quality were excluded. Results were statistically compared to an LC-MS/MS method that previously demonstrated excellent comparability to a candidate reference method. The Roche gen II showed a mean bias of -2.4nmol/L and a Passing-Bablok fit of y = -0.9 + 0.97x. This was not affected by sex. The Abbott showed a mean bias -18.8nmol/L, and a fit of y = -11.3 + 0.88x. This bias was -20.7nmol/L in females versus -17.2nmol/L in males. The Siemens had a mean bias of 2.3nmol/L and a fit of y = 1.4 + 1.07x. This bias was 5.7nmol/L in males versus -1.0nmol/L in females. Clinicians should be aware of the method-dependent variation that exists within serum cortisol analysis during the ONDSTs. Roche and Siemens aligned more closely with LC-MS/MS while the Abbot may cause a reduction in ONDST sensitivity. This data supports assay-specific cut-offs for the ONDST.

Evaluation of Ortho VITROS and Roche Elecsys S and NC Immunoassays for SARS-CoV-2 Serosurveillance Applications.

SARS-CoV-2 seroprevalence studies are instrumental in monitoring epidemic activity and require well-characterized, high-throughput assays, and appropriate testing algorithms. The U.S. Nationwide Blood Donor Seroprevalence Study performed monthly cross-sectional serological testing from July 2020 to December 2021, implementing evolving testing algorithms in response to changes in pandemic activity. With high vaccine uptake, anti-Spike (S) reactivity rates reached >80% by May 2021, and the study pivoted from reflex Roche anti-nucleocapsid (NC) testing of Ortho S-reactive specimens to parallel Ortho S/NC testing. We evaluated the performance of the Ortho NC assay as a replacement for the Roche NC assay and compared performance of parallel S/NC testing on both platforms. Qualitative and quantitative agreement of Ortho NC with Roche NC assays was evaluated on preselected S/NC concordant and discordant specimens. All 190 Ortho S+/Roche NC+ specimens were reactive on the Ortho NC assay; 34% of 367 Ortho S+/Roche NC- specimens collected prior to vaccine availability and 43% of 37 Ortho S-/Roche NC+ specimens were reactive on the Ortho NC assay. Performance of parallel S/NC testing using Ortho and Roche platforms was evaluated on 200 specimens collected in 2019 and 3,903 study specimens collected in 2021. All 200 pre-COVID-19 specimens tested negative on the four assays. Cross-platform agreement between Roche and Ortho platforms was 96.4% (3,769/3,903); most discordant results had reactivity close to the cutoffs on the alternate assays. These findings, and higher efficiency and throughput, support the use of parallel S/NC testing on either Roche or Ortho platforms for large serosurveillance studies. IMPORTANCE Seroprevalence studies like the U.S. Nationwide Blood Donor Seroprevalence Study (NBDS) have been critical in monitoring SARS-CoV-2 epidemic activity. These studies rely on serological assays to detect antibodies indicating prior infection. It is critical that the assays and testing algorithms used in seroprevalence studies have adequate performance (high sensitivity, high specificity, ability to discriminate vaccine-induced and infection-induced antibodies, etc.), as well as appropriate characteristics to support large-scale studies, such as high throughput and low cost. In this study we evaluated the performance of Ortho's anti-nucleocapsid assay as a replacement for the Roche anti-nucleocapsid assay and compared performance of parallel anti-spike and anti-nucleocapsid testing on both platforms. These data demonstrate similar performance of the Ortho and Roche anti-nucleocapsid assays and that parallel anti-spike and anti-nucleocapsid testing on either platform could be used for serosurveillance applications.

P-690 RESEarch on ovarian reseRVE among Neurologic patients: the RESERVEN study

Abstract Study question Could Multiple Sclerosis (MS) reduce the levels of main ovarian reserve markers, measured through automated systems? Summary answer There is no statistically significant difference in ovarian reserve markers between women affected by Multiple Sclerosis and healthy controls. What is known already Few studies evaluated the issue of ovarian reserve in women affected by MS, so far. The majority of them observed no differences in ovarian reserve markers between women affected by MS and healthy controls. However, interestingly, women with MS in case of a more active disease were observed to have lower levels of ovarian reserve markers. In fact, evidence suggests that an inflammatory status may reduce the ovarian reserve, where autoimmune-related diseases are considered a possible cause of Premature Ovarian Insufficiency (POI). Study design, size, duration This is a single-center multidisciplinary prospective case-control (44 cases and 72 controls) study performed from September 2019 to September 2022. Participants/materials, setting, methods Cases were reproductive-age women affected by MS recruited at our MS unit, controls were age- and body mass index (BMI) - matched healthy women recruited at our assisted reproductive technology (ART) unit. During the early follicular phase, a transvaginal ultrasound was performed with sonoAVC software (GE medical systems) for 3D antral follicle count and a blood sample taken for hormonal assays (Anti-Müllerian hormone levels was measured using the Roche Elecsys AMH Plus). Main results and the role of chance There are no differences in age (p = 0.11), BMI (p = 0.96) as per protocol. Moreover, differences in FSH (p = 0.14), LH (p = 0.13), estradiol (p = 0.92), and AMH (p = 0.99) levels were not statistically significant. The 3D antral follicle count showed a statistically significant difference (p = 0.03), but following a re-evaluation of pictures in post-processing, removing the small antral follicles (2-4 mm) the difference was not statistically significant (p = 0.14). Limitations, reasons for caution We could not assess women before they started on medication for MS. Therefore, we could not exclude that medication have an impact in these results, also because the sample is small and patients were not treated with the same drug. Moreover, all patients were in disease remission at enrollment. Wider implications of the findings This is the first study to evaluate ovarian reserve markers with automated systems. Our results confirmed the ones previously published. However, the interesting data on 3D antral follicle count increased in MS women should be confirmed and studied in order to evaluate if follicular dynamics are altered in Multiple Sclerosis. Trial registration number Not applicable

P-657 Elecys anti-Müllerian hormone thresholds for defining ovarian response categories; comparison of published and novel values in 7,988 treatment naïve women

Abstract Study question Test the accuracy of published and novel AMH thresholds in predicting (low, sub-optimal, optimal and high) ovarian response categories in first treatment cycles. Summary answer Published AMH thresholds for poor and excessive ovarian response perform adequately, however, prediction of suboptimal or optimal oocyte yields is difficult reflecting their limited range. What is known already AMH is an established predictor of ovarian response, and can identify women at risk of poor (<4 oocytes) or excessive (>15 oocytes) response. With the development of suboptimal (4 to 9 oocytes) and optimal (10 to 14 oocytes) response categories, a series of AMH ranges for the Roche Elcesys AMH assay has been proposed to predict response for all four categories (AMH <6.4pmol/l, 4.9–11.3 pmol/l, 11.3–20.9 pmol/l, and >14.2 pmol/l). To date there has been no internal or external validation of these single centre derived thresholds, and it is unknown whether they are generalisable to other clinic populations. Study design, size, duration Observational cohort study from 8 UK clinics, incorporating 7,998 women undertaking their first ovarian stimulation cycle for assisted conception or fertility preservation between 2016 and 2022, with a pre-treatment AMH measured using the Roche Elecsys AMH assay. Both GnRH agonist and antagonist cycles were included, with triggering by either recombinant hCG or GnRH agonist once 3 follicles were ³18mm in size with oocyte retrieval performed 36h later. Participants/materials, setting, methods To give equal opportunity to the published and novel thresholds, patients were divided into training (5,330) and testing (2,668) sets. Novel cut-off points for a low, sub-optimal, optimal and high response were derived in the training set. The performance of these novel thresholds and those of published values were then assessed and compared in the testing set by their respective AUC, and precision as defined as the fraction of correct predictions for a certain class. Main results and the role of chance Baseline patient characteristics (mean, SD) were 35.1±4.7 years; BMI 25.5±4.4 kg/m2, with a median AMH 15.2 pmol/l (IQR 8, 26) and a median of 11 (IQR 6,16) oocytes retrieved. These baseline characteristics and outcomes were similar after splitting in the training and testing datasets. Baseline AMH and oocytes collected were moderately correlated (r = 0.54, p < 0.001). 465 (5.8%) cycles were cancelled due to not meeting trigger criteria and classed as poor/low responders. The novel thresholds for low oocyte yield (≤10.05 pmol/l) provided similar performance (AUC 0.70 95%CI 0.66-0.74, sensitivity 0.69, specificity 0.74) to the published thresholds (AUC 0.67, 95%CI 0.62-0.72) in the testing population. Similarly, the novel high (15.9pmol/l) threshold (AUC 0.78, 95%CI 0.75-0.81, sensitivity 0.78, specificity 0.64) exhibited similar performance to the published threshold AUC 0.77, 95%CI 0.74,0.81) in the testing population. Deriving novel thresholds for prediction of 4 categories of response (6.7, 12.9, 18.9pmol) was associated with slightly better precision for low, suboptimal and high categories (p < 0.001), with the fraction of correct predictions for a certain category of response for the novel cut-points; 69.0 % low, 11.7% suboptimal, 14.1% optimal and 78.3% high, as compared to 52.0%, 27.8%, 12.9% and 83.8% respectively for the published values. Limitations, reasons for caution While designing the ovarian stimulation strategies clinicians were aware of the baseline AMH and targeted a perceived optimal response for cumulative live birth (∼15 oocytes), which may have contributed to the performance of both the established and novel AMH thresholds. Wider implications of the findings In a large heterogenous population of women undergoing their first treatment cycle, we confirm the appropriateness of the previously published Elecsys AMH values for prediction of low (<6.4pmol/l) and high (>14.2pmol/l) oocyte yields. Trial registration number N/A

The Kinetics of Anti-SARS-CoV-2 Antibodies in Pediatric Patients and the Characterization of Post-COVID-19 Condition at 6 Months After Infection: Protocol for a Longitudinal Observational Study.

Data regarding the kinetics of anti-SARS-CoV-2 antibodies and information about post-COVID-19 condition (colloquially known as "long COVID") in children are scarce, especially in low-income countries. Even though cases of COVID-19 in children are less prevalent than adults, post-COVID-19 condition cases in children are high and have a burden that may impact their growth and development. There are other features of antibody kinetics in connection with SARS-CoV-2 infection that are yet unknown as of this writing, especially in children following infection. Furthermore, the long-term results, risk factors, and underlying pathophysiology are still uncertain. To better understand post-COVID-19 condition in children, it is necessary to further investigate the impact of clinically significant factors such multisystem inflammatory syndrome and disease severity among hospitalized survivors through their SARS-CoV-2 antibody response. We aim to analyze anti-receptor-binding domain SARS-CoV-2 immunoglobulin G antibodies over time and characterize the signs and symptoms of post-COVID-19 condition in pediatric patients at the time of diagnosis and at 2 weeks and 1, 3, and 6 months following infection. This is a longitudinal observational study in Indonesia. Pediatric patients diagnosed with COVID-19 by positive molecular assay using nasopharyngeal swab will be tested for anti-SARS-CoV-2 antibodies using the Roche Elecsys Anti-SARS-CoV-2 S assay at the time of diagnosis and at 2 weeks and 1, 3, and 6 months following infection. Antibody titer data will be reported as means and SDs. The respondents' signs and symptoms will be observed up to 6 months after the onset of infection, including the vaccination event, reinfection, rehospitalization, and mortality. The clinical features will be reported as frequencies and percentages. Participant enrollment began in February 2022. As of September 30, 2022, a total of 58 patients were enrolled. After data collection, results are expected to be analyzed in August 2023. This study will allow us to know the kinetics of anti-receptor-binding domain SARS-CoV-2 immunoglobulin G antibodies and data regarding post-COVID-19 condition up to 6 months following infection in the Indonesian pediatric population. Furthermore, this study has the potential to serve as a foundation for government decisions about vaccination programs and prevention measures. DERR1-10.2196/43344.

AMHconverter: an online tool for converting results between the different anti-Müllerian hormone assays of Roche Elecsys®, Beckman Access, and Kangrun.

The anti-Müllerian hormone (AMH) is gaining attention as a key factor in determining ovarian reserve and polycystic ovarian syndrome, and its clinical applications are becoming more widespread worldwide. To identify the most accurate formula for converting AMH assay results between different platforms, so that the developed AMH converter can be used to reduce the need for multiple AMH tests at different hospitals. Assuming that the Beckman Access, Kangrun, and Roche Elecsys® AMH assays fit a linear relationship from the lowest to the highest concentration (a global relationship), we used Passing-Bablok regression to determine the conversion equation between each two assays. When the relationship between two AMH assays was a local one, spline regression was used. Bland-Altman plots were drawn to check systemic bias and heterogeneity of variance across different ranges of values. The fitting effects of the models were evaluated using the squared coefficient of determination (r2), adjusted r2, root mean square error (RMSE), Akaike information criterion (AIC), and corrected AIC. The coefficient of variance for multiple controls in the Kangrun, Roche, and Beckman assays was lower than 5%, and the bias of multiple controls was lower than 7%. A global linear relationship was observed between the Kangrun and Roche assays, with the intercept being zero, for which Passing-Bablok regression was employed for data conversion between the two platforms. For the other two pairs of platforms, i.e., Roche and Kangrun or Beckman and Kangrun, spline regression was applied, with the intercepts not including zero. The six corresponding formulas were developed into an online AMH converter (http://121.43.113.123:8006/). This is the first time Passing-Bablok plus spline regression has been used to convert AMH concentrations from one assay to another. The formulas have been developed into an online tool, which makes them convenient to use in practical applications.

Variation in antibody titers determined by Abbott and Roche Elecsys SARS-CoV-2 assays in vaccinated healthcare workers

SARS-CoV-2-specific antibody measurement is important for evaluating COVID-19 vaccine efficacy. We quantified and compared anti-spike (S) antibodies using different commercial immunoassays. We tested serum samples from 70 SARS-CoV-2-naive health care workers 2 weeks after vaccination with a single dose of BNT162b2, 2 and 4 weeks, and 3 months after the second dose of BNT162b2. The following quantitative assays were used: Roche Elecsys Anti-SARS-CoV-2 S (Roche-S), Abbott SARS-CoV-2 IgG II Quant [Abbott-IgG(S)], and Abbott SARS-CoV-2 IgM (Abbott-IgM). All samples tested positive for Roche-S and Abbott-IgG antibodies after the second dose, with 83.6% Abbott-IgM positive rate. Roche-S and Abbott-IgG(S) correlated significantly in all samples (r = 0.920, p < 0.0001), and the Roche-S and Abbott-IgG(S) assay showed a strong correlation with each other at each time point after vaccination. Roche-S and Abbott-IgG(S) antibody titers were correlated with age; their rate of decline was age-dependent in males but not in females. Abbott-IgG(S) antibody titers decreased from 2 weeks after the second dose. Roche-S antibody titers peaked 2 weeks after the second dose in 76.2% of the participants; the titers recovered 3 months post-vaccination after declining at week 4 in 40.7% of the participants. The concordance between Roche-S and Abbott-IgG(S) antibody titers over time was 47.5%. Most participants presented significantly high Roche-S and Abbott-IgG(S) antibody titers after immunization. Some measurements were inconsistent with titer changes between these assays, possibly because of differences in the immunoglobulin-specificity of the kits.

Factors Associated with Reported COVID-like Symptoms and Seroprevalence Data Matched with COVID-like Symptoms in Slums and Non-Slums of Two Major Cities in Bangladesh.

To examine the levels and socio-demographic differentials of: (a) reported COVID-like symptoms; and (b) seroprevalence data matched with COVID-like symptoms. Survey data of reported COVID-like symptoms and seroprevalence were assessed by Roche Elecsys® Anti-SARS-CoV-2 immunoassay. Survey data of 10,050 individuals for COVID-like symptoms and seroprevalence data of 3205 individuals matched with COVID-like symptoms were analyzed using bivariate and multivariate logistic analysis. The odds of COVID-like symptoms were significantly higher for Chattogram city, for non-slum, people having longer years of schooling, working class, income-affected households, while for households with higher income had lower odd. The odds of matched seroprevalence and COVID-like symptoms were higher for non-slum, people having longer years of schooling, and for working class. Out of the seropositive cases, 37.77% were symptomatic-seropositive, and 62.23% were asymptomatic, while out of seronegative cases, 68.96% had no COVID-like symptoms. Collecting community-based seroprevalence data is important to assess the extent of exposure and to initiate mitigation and awareness programs to reduce COVID-19 burden.

Differential absolute plasma IL-6 concentrations between two immunoassay platforms in intensive care unit patients with COVID-19.

Objectives: Explorewhether plasma IL-6 levels are similar across biomarker platforms and association with COVID-19 clinical outcomes. Methods: Plasma IL-6 concentrations were measured on 191 COVID-19 patients using the Roche Elecsys IL-6 assay and the Meso Scale Discoveryassay. Results: Correlation of IL-6 levels between platforms was high (r=0.87;95% CI: 0.82-0.89); however, agreement was low (bias: 147.2pg/ml; 95% limits of agreement: -489.5-783.9pg/ml). The optimal IL-6 threshold to predict invasive mechanical ventilation and in-hospital mortality were 3- and 3.4-fold higher in Roche compared with Meso Scale Discovery, respectively. Conclusion: The absolute IL-6 threshold to predict outcomes was consistently higher using the Roche platform, and IL-6 thresholds to inform prognosis vary based on the biomarker platform.

Evaluation of the Diagnostic Performance of Two Automated SARS-CoV-2 Neutralization Immunoassays following Two Doses of mRNA, Adenoviral Vector, and Inactivated Whole-Virus Vaccinations in COVID-19 Naïve Subjects.

Limited data are available on humoral responses determined by automated neutralization tests following the administration of the three different types of COVID-19 vaccinations. Thus, we here evaluated anti-SARS-CoV-2 neutralizing antibody titers via two different neutralization assays in comparison to total spike antibody levels. Healthy participants (n = 150) were enrolled into three subgroups who were tested 41 (22-65) days after their second dose of mRNA (BNT162b2/mRNA-1273), adenoviral vector (ChAdOx1/Gam-COVID-Vac) and inactivated whole-virus (BBIBP-CorV) vaccines, with no history or serologic evidence of prior SARS-CoV-2 infection. Neutralizing antibody (N-Ab) titers were analyzed on a Snibe Maglumi® 800 instrument and a Medcaptain Immu F6® Analyzer in parallel to anti-SARS-CoV-2 S total antibody (S-Ab) levels (Roche Elecsys® e602). Subjects who were administered mRNA vaccines demonstrated significantly higher SARS-CoV-2 N-Ab and S-Ab levels compared to those who received adenoviral vector and inactivated whole-virus vaccinations (p < 0.0001). N-Ab titers determined by the two methods correlated with each other (r = 0.9608; p < 0.0001) and S-Ab levels (r = 0.9432 and r = 0.9324; p < 0.0001, respectively). Based on N-Ab values, a new optimal threshold of Roche S-Ab was calculated (166 BAU/mL) for discrimination of seropositivity showing an AUC value of 0.975 (p < 0.0001). Low post-vaccination N-Ab levels (median value of 0.25 μg/mL or 7.28 AU/mL) were measured in those participants (n = 8) who were infected by SARS-CoV-2 within 6 months after immunizations. Both SARS-CoV-2 N-Ab automated assays are effective to evaluate humoral responses after various COVID-19 vaccines.

SARS-CoV-2 Serostatus and COVID-19 Illness Characteristics by Variant Time Period in Non-Hospitalized Children and Adolescents.

To describe COVID-19 illness characteristics, risk factors, and SARS-CoV-2 serostatus by variant time period in a large community-based pediatric sample. Data were collected prospectively over four timepoints between October 2020 and November 2022 from a population-based cohort ages 5 to 19 years old. State of Texas, USA. Participants ages 5 to 19 years were recruited from large pediatric healthcare systems, Federally Qualified Healthcare Centers, urban and rural clinical practices, health insurance providers, and a social media campaign. SARS-CoV-2 infection. SARS-CoV-2 antibody status was assessed by the Roche Elecsys® Anti-SARS-CoV-2 Immunoassay for detection of antibodies to the SARS-CoV-2 nucleocapsid protein (Roche N-test). Self-reported antigen or PCR COVID-19 test results and symptom status were also collected. Over half (57.2%) of the sample (N = 3911) was antibody positive. Symptomatic infection increased over time from 47.09% during the pre-Delta variant time period, to 76.95% during Delta, to 84.73% during Omicron, and to 94.79% during the Omicron BA.2. Those who were not vaccinated were more likely (OR 1.71, 95% CI 1.47, 2.00) to be infected versus those fully vaccinated. Results show an increase in symptomatic COVID-19 infection among non-hospitalized children with each progressive variant over the past two years. Findings here support the public health guidance that eligible children should remain up to date with COVID-19 vaccinations.

Serologic Response and Clinical Outcomes of SARS-CoV-2 Infection and Vaccination in Ozanimod-Treated Participants With Relapsing Multiple Sclerosis (P2-3.018)

Serologic Response and Clinical Outcomes of SARS-CoV-2 Infection and Vaccination in Ozanimod-Treated Participants With Relapsing Multiple Sclerosis (P2-3.018)

P011 Rituximab and COVID-19 vaccines; are they fit for purpose?

Abstract Background/Aims Since the COVID-19 outbreak the rheumatology community have been concerned about the risk of SARS-CoV-2 infection in patients prescribed immunosuppressing medications. Data suggests that patients receiving Rrtuximab are at increased risk of developing severe outcomes from COVID-19 (1). In our unit all patients receiving rituximab were selected to receive a targeted vaccination and booster programme with all patients receiving at least 2 vaccinations and up to 3 booster vaccinations. We studied the efficacy of the COVID-19 vaccines in rituximab patients, by checking the the Roche Elecsys Anti-SARS-CoV-2-S (Spike) IgG/IgM total antibody levels post vaccination. Our aim was to assess the vaccination response in patients receiving rituximab and to offer advice on continued shielding or alternatively passive immunization with tixagevimab/cilgavimab in those patients who did not mount a response. Methods Taking 39 patients currently on rituximab therapy, we measured Anti-SARS-CoV-2-S (Spike) antibody levels post vaccination. We recorded whether the test was positive or negative, and the numerical result. We recorded rituximab dates of administration and dates of vaccines. We also recorded diagnosis, co-prescribed DMARDs, immunoglobulin levels, white cell and lymphocyte counts. We took record of whether or not the patient subsequently contracted COVID-19, required a hospital admission, ICU or died. Results Of our 39 patients, 21 had Anti-SARS-CoV-2-S (Spike) antibody levels checked. Of these patients, 7 (33%) had a negative spike protein result. Of the patients with a positive result, 8 (38%) had an antibody level between 0-250U/ML, and only 6 (28.6%) had a level &amp;gt;250U/ML (The manufacturer advises that a level above 0.8U/ML is a positive result). Of patients with a negative result, 1 patient had received 3 vaccines, 5 patients had received 4, and 1 patient had 5. All of the patients had received a vaccine &amp;gt;4 weeks prior to receiving the drug. Two patients were co-prescribed Belimumab, 3 were co-prescribed low-dose methotrexate and 2 were not on additional disease modifying agents. The diagnoses of these patients were, 2 patients with SLE, 4 with SPRA, and 1 MPO Vasculitis. There were no significant findings in lymphocyte count, white cell count or immunoglobulin levels. Conclusion These findings suggest that our current COVID-19 vaccination and booster programme may not provide adequate response in patients receiving rituximab therapy. Despite this being a small cohort, these results show that 33% of patients have not mounted a vaccine response and this is concerning. We suggest that vaccine response should be checked in all patients receiving rituximab therapy and those patients who do not mount a vaccine response should be offered passive immunity and advised of possible additional risks regarding COVID-19 exposure. Disclosure S.K. Stewart: None. A. Pendleton: None.

Validation of N Protein Antibodies to Diagnose Previous SARS-CoV-2 Infection in a Large Cohort of Healthcare Workers: Use of Roche Elecsys® Immunoassay in the S Protein Vaccination Era.

The aim of this study was to validate the detection of anti-nucleocapsid protein (N protein) antibodies for the diagnosis of SARS-CoV-2 infection in light of the fact that most COVID-19 vaccines use the spike (S) protein as the antigen. Here, 3550 healthcare workers (HCWs) were enrolled from May 2020 (when no S protein vaccines were available). We defined SARS-CoV-2 infection if HCWs were found to be positive by RT-PCR or found to be positive in at least two different serological immunoassays. Serum samples from Biobanc I3PT-CERCA were analyzed by Roche Elecsys® (N protein) and Vircell IgG (N and S proteins) immunoassays. Discordant samples were reanalyzed with other commercial immunoassays. Roche Elecsys® showed the positivity of 539 (15.2%) HCWs, 664 (18.7%) were found to be positive by Vircell IgG immunoassays, and 164 samples (4.6%) showed discrepant results. According to our SARS-CoV-2 infection criteria, 563 HCWs had SARS-CoV-2 infection. The Roche Elecsys® immunoassay has a sensitivity, specificity, accuracy, and concordance with the presence of infection of 94.7%, 99.8%, 99.3%, and 0.96, respectively. Similar results were observed in a validation cohort of vaccinated HCWs. We conclude that the Roche Elecsys® SARS-CoV-2 N protein immunoassay demonstrated good performance in diagnosing previous SARS-CoV-2 infection in a large cohort of HCWs.

Increased SARS-CoV-2 seroprevalence and spread of infection without awareness among healthcare workers through 2020–2022 in a Japanese medical center

Despite Japan’s high vaccination coverage, daily numbers of new COVID-19 cases have been high. However, studies on the seroprevalence among Japanese people and the causative factors for rapid spread have remained limited. In this study, we aimed to examine the seroprevalence and associated factors in healthcare workers (HCWs) of a medical center in Tokyo using blood samples drawn at annual check-ups from 2020 to 2022. We found that of the 3,788 HCWs in 2022 (by mid-June), 669 were seropositive for N-specific antibodies (tested by Roche Elecsys Anti-SARS-CoV-2 assay); the seroprevalence surged from 0.3% in 2020 and 1.6% in 2021 to 17.7% in 2022. Notably, our study found 325 (48.6%; 325/669) cases were infected without awareness. Among those with a previously PCR-confirmed SARS-CoV-2 infection during the past three years, 79.0% (282/357) were found after January 2022, after the Omicron variant was first detected in Tokyo at the end of 2021. This study indicates the fast spread of the SARS-CoV-2 among HCWs during the Omicron surge in Japan. The high percentage of infection without awareness may be a key driving factor causing rapid person-to-person transmission, as shown in this medical center with high vaccination coverage and strict infection control measures.

Cellular and humoral immunogenicity of the COVID-19 vaccine and COVID-19 disease severity in individuals with immunodeficiency.

A well-coordinated adaptive immune response is crucial for limiting COVID-19 disease. Some individuals with immunodeficiency are at a high risk of developing severe COVID-19. Therefore, the development of standardized methods for measuring different arms of the vaccine response in the setting of immunodeficiency is of particular interest. In this study, we compared the vaccine response of individuals living with immunodeficiency with healthy controls in terms of interferon gamma (IFN-γ) production and spike protein-specific antibody level post primary COVID-19 vaccination and booster vaccines. Additionally, the disease severity of those individuals who contracted COVID-19 was assessed. Whole blood was stimulated overnight from 71 participants and 99 healthy controls. Commercially available PepTivator® peptide pool and trimeric spike protein stimulation were used. ELISA was used to analyze IFN-γ levels. The total SARS-CoV-2 spike protein antibody titre was measured using a Roche Elecsys® S total antibody assay. Patient characteristics, COVID-19 infection status and IDDA 2.1 'Kaleidoscope' scores were recorded. Vaccine responses were scored from zero to three. 99% of healthy controls, 89% of individuals with IEI and 76% with secondary immunodeficiency (SID) had an IFN-γ level above the validated reference range after peptide mix stimulation following primary vaccination. There was an increase in IFN-γ levels in patients with inborn errors of immunity (IEI) following the booster vaccine (p = 0.0156). 100% of healthy controls, 70% of individuals living with IEI and 64% of individuals living with SID had detectable spike protein-specific antibody levels following the primary vaccination. 55% of immunodeficiency patients who had mild COVID-19 and 10% with moderate/severe COVID-19 had detectable antibody and IFN-γ levels post vaccine. The mean pre-infection IDDA 2.1 scores were higher in individuals who developed moderate/severe COVID-19 (25.2 compared to 9.41). Covid whole-blood IGRA is a highly accurate, straightforward and robust assay and can be easily adapted to measure cellular response to COVID-19. A complete evaluation of the vaccine response may be particularly important for individuals living with immunodeficiency. A clinical immunodeficiency score and a validated vaccine response score may be valuable tools in estimating COVID-19 disease risk and identifying individuals living with immunodeficiency who may benefit from enhanced vaccination schedules.

Antibody response to different COVID-19 vaccines among the migrant workers of Bangladesh.

Due to the ongoing COVID-19 pandemic, various host countries such as Singapore, imposed entry requirements for migrant workers including pre-departure COVID-19 seroconversion proof. To combat COVID-19 worldwide, several vaccines have acquired conditional approval. This study sought to assess antibody levels after immunization with different COVID-19 vaccines among the migrant workers of Bangladesh. Venous blood samples were collected from migrant workers who were vaccinated with different COVID-19 vaccines (n=675). Antibodies to SARS-CoV-2 spike protein (S) and nucleocapsid protein (N) were determined using Roche Elecsys® Anti-SARS-CoV-2 S and N immunoassay, respectively. All participants receiving COVID-19 vaccines showed antibodies to S-protein, while 91.36% were positive for N-specific antibodies. The highest anti-S antibody titers were found among the workers who completed booster doses (13327 U/mL), received mRNA vaccines Moderna/Spikevax (9459 U/mL) or Pfizer-BioNTech/Comirnaty (9181 U/mL), and reported SARS-CoV-2 infection in the last six months (8849 U/mL). The median anti-S antibody titers in the first month since the last vaccination was 8184 U/mL, which declined to 5094 U/mL at the end of six months. A strong correlation of anti-S antibodies was found with past SARS-CoV-2 infection (p < 0.001) and the type of vaccines received (p <0.001) in the workers.Conclusion: Bangladeshi migrant workers receiving booster doses of vaccine, vaccinated with mRNA vaccines, and having past SARS-CoV-2 infection, mounted higher antibody responses. However, antibody levels waned with time. These findings suggest a need for further booster doses, preferably with mRNA vaccines for migrant workers before reaching host countries.

Impact of Omicron Variant Infection on Assessment of Spike-Specific Immune Responses Using the EUROIMMUN Quan-T-Cell SARS-CoV-2 Assay and Roche Elecsys Anti-SARS-CoV-2-S

The currently prevailing variants of SARS-CoV-2 are subvariants of the Omicron variant. The aim of this study was to analyze the effect of mutations in the Spike protein of Omicron on the results Quan-T-Cell SARS-CoV-2 assays and Roche Elecsys anti-SARS-CoV-2 anti-S1. Omicron infected subjects ((n = 37), vaccinated (n = 20) and unvaccinated (n = 17)) were recruited approximately 3 weeks after a positive PCR test. The Quan-T-Cell SARS-CoV-2 assays (EUROIMMUN) using Wuhan and the Omicron adapted antigen assay and a serological test (Roche Elecsys anti-SARS-CoV-2 anti-S1) were performed. Using the original Wuhan SARS-CoV-2 IGRA TUBE, in 19 of 21 tested Omicron infected subjects, a positive IFNy response was detected, while 2 non-vaccinated but infected subjects did not respond. The Omicron adapted antigen tube resulted in comparable results. In contrast, the serological assay detected a factor 100-fold lower median Spike-specific RBD antibody concentration in non-vaccinated Omicron infected patients (n = 12) compared to patients from the pre Omicron era (n = 12) at matched time points, and eight individuals remained below the detection threshold for positivity. For vaccinated subjects, the Roche assay detected antibodies in all subjects and showed a 400 times higher median specific antibody concentration compared to non-vaccinated infected subjects in the pre-Omicron era. Our results suggest that Omicron antigen adapted IGRA stimulator tubes did not improve detection of SARS-CoV-2-specific T-cell responses in the Quant-T-Cell-SARS-CoV-2 assay. In non-vaccinated Omicron infected individuals, the Wuhan based Elecsys anti-SARS-CoV-2 anti-S1 serological assay results in many negative results at 3 weeks after diagnosis.

Pre-analytical considerations in the development of a prototype SARS-CoV-2 antigen ARCHITECT automated immunoassay.

To evaluate pre-analytical challenges related to high-volume central laboratory SARS-CoV-2 antigen testing with a prototype qualitative SARS-CoV-2 antigen immunoassay run on the automated Abbott ARCHITECT instrument. Contrived positive and negative specimens and de-identified nasal and nasopharyngeal specimens in transport media were used to evaluate specimen and reagent on-board stability, assay analytical performance and interference, and clinical performance. TCID50/mL values were similar for specimens in various transport media. Inactivated positive clinical specimens and viral lysate (USA-WA1/2020) were positive on the prototype immunoassay. Within-laboratory imprecision was≤0.10 SD (<1.00S/C) with a≤10% CV (≥1.00S/C). Assay reagents were stable on board the instrument for 14days. No high-dose hook effect was observed with a SARS-CoV-2 stock of Ct 13.0 (RLU>1.0×106). No interference was observed from mucin, whole blood, 12 drugs, and more than 20 cross-reactants. While specimen stability was limited at room temperature for specimens with or without viral inactivation, a single freeze/thaw cycle or long-term storage (>30days) at-20°C did not adversely impact specimen stability or assay performance. Specificity of the prototype SARS-CoV-2 antigen immunoassay was≥98.5% and sensitivity was≥89.5% across two ARCHITECT instruments. Assay sensitivity was inversely correlated with Ct and was similar to that reported for the Roche Elecsys® SARS-CoV-2 Ag immunoassay. The prototype SARS-CoV-2 antigen ARCHITECT immunoassay is sensitive and specific for detection of SARS-CoV-2 in nasal and nasopharyngeal specimens. Endogenous proteases in mucus may degrade the target antigen, which limits specimen storage and transport times and complicates assay workflow.