COVID-19 Antibody Tests Research Articles

Validation of Ethical COVID-19 Antibody Testing that Adheres to Pro-Life Principles.

We describe validation of a COVID-19 antibody test for detection of anti-SARS-CoV-2 receptor-binding domain (RBD) IgG antibodies in blood plasma utilizing ethically sourced reagents not derived from aborted fetal cell lines. The test demonstrated specificity of 100% (95% confidence intervals 77.2-100%) and sensitivity of 100% (95% confidence intervals 79.6-100%) when evaluating blood specimens previously determined to be negative (n = 13) or positive for anti-SARS-CoV-2 RBD IgG antibodies due to natural SARS-CoV-2 exposure (n = 13) or COVID-19 vaccination (n = 15). The test was used to screen 230 blood specimens from individuals with unknown SARS-CoV-2 exposure (n = 103) or that were naturally exposed to SARS-CoV-2 (n = 44), received a COVID-19 vaccine (n = 66), or received a COVID-19 vaccine before or after SARS-CoV-2 exposure (n = 17). Ninety-nine percent (95% confidence intervals 95.7-100%) of the 127 blood specimens from individuals that were naturally exposed, vaccinated, or both vaccinated and naturally exposed were positive for anti-SARS-CoV-2 RBD IgG which was consistent with the high sensitivity of our test. This COVID-19 antibody test, now named the PL COVID-19 RBD IgG antibody test, represents an effective and ethical alternative to commercially available COVID-19 antibody tests that utilize reagents derived from aborted fetal lines.

The value of using COVID-19 antibody tests as a potential approach to prioritize vaccination delivery.

The highly contagious novel COVID-19 virus has demonstrated a great challenge for healthcare workers (HCWs) worldwide. One of these challenges is the availability of vaccines in some countries or societies, especially in the early stages of the pandemic. This study aims to determine the level of natural immunity against COVID-19 infection among HCWs exposed to COVID-19 at the early stages of the pandemic and build a model to determine the groups that can benefit more from the scarce vaccination resources. This study took place between January and March 2021, after the first waves of the COVID-19 pandemic, before spreading the variants of concern, such as the UK variant (Alpha B.1.1.7), and before starting the vaccine campaigns. This cross-sectional study collected serum samples from 251 vulnerable HCWs. The samples were tested for IgG antibodies against COVID-19 using commercial kits. The demographics and clinical characteristics of the participants were recorded using face-to-face interviews. COVID-19 IgG antibodies were detected in more than 40% of HCWs before vaccination. Those HCWs should have less priority than those without COVID-19 IgG. The seroprevalence of COVID-19 was higher in male HCWs and among nurses. There was no association between the participants' immunity and smoking status or different blood groups. Most HCWs reported being infected with the virus during the first wave, mainly at the end of 2020. A limited number of HCWs reported infections between January 2021 and March 2021. All HCWs eventually received the COVID-19 vaccine, ignoring being previously infected. The reported results emphasize the value of using immunity tests to prioritize the groups that may benefit the most from the limited vaccines, especially in developing countries with scarce resources where those with COVID-19 IgG antibodies should have less priority for the COVID-19 vaccine. The present results indicate that up to 40% of the delivered vaccines to HCWs who had COVID-19 antibodies could be prioritized more wisely in future pandemics.

COVID-19 in patients presenting with malaria-like symptoms at a primary healthcare facility in Accra, Ghana.

Malaria is a common and severe public health problem in Ghana and largely responsible for febrile symptoms presented at health facilities in the country. Other infectious diseases, including COVID-19, may mimic malaria due to their shared non-specific symptoms such as fever and headache thus leading to misdiagnosis. This study therefore investigated COVID-19 among patients presenting with malaria-like symptoms at Korle-Bu Polyclinic, Accra, Ghana. This study enrolled 300 patients presenting with malaria-like symptoms aged ≥18yrs. After consent was obtained from study patients, two to three millilitres of whole blood, nasopharyngeal and oropharyngeal swab samples, were collected for screening of Plasmodium falciparum using malaria rapid diagnostic test, microscopy and nested PCR, and SARS-CoV-2 using SARS-CoV-2 antigen test and Real-time PCR, respectively. The plasma and whole blood were also used for COVID-19 antibody testing and full blood counts using hematological analyser. SARS-CoV-2 whole genome sequencing was performed using MinIon sequencing. The prevalence of malaria by microscopy, RDT and nested PCR were 2.3%, 2.3% and 2.7% respectively. The detection of SARS-CoV-2 by COVID-19 Rapid Antigen Test and Real-time PCR were 8.7% and 20% respectively. The Delta variant was reported in 23 of 25 SARS-CoV-2 positives with CT values below 30. Headache was the most common symptom presented by study participants (95%). Comorbidities reported were hypertension, asthma and diabetes. One hundred and thirteen (37.8%) of the study participants had prior exposure to SARS CoV-2 and (34/51) 66.7% of Astrazeneca vaccinated patients had no IgG antibody. It may be difficult to use clinical characteristics to distinguish between patients with COVID-19 having malaria-like symptoms. Detection of IgM using RDTs may be useful in predicting CT values for SARS-CoV-2 real-time PCR and therefore transmission.

Detection of Specific Immunoglobulins in the Saliva of Patients With Mild COVID-19.

Saliva has many advantages over blood as a biofluid, so using it for measuring and monitoring antibody responses in COVID-19 would be highly valuable. To assess the value of saliva-based IgG and IgM/IgA antibody testing in COVID-19, this cross-sectional pilot study evaluated the accuracy of salivary and serum IgG and IgM/IgA for detecting mild COVID-19 and their correlation. Fifty-one patients with mild COVID-19 (14-28 days post-symptom onset) were included in the study. Enzyme-linked immunosorbent assays (ELISA) were used to measure IgG and IgM/IgA responses to SARS-CoV-2 spike protein in both serum and saliva samples using a slightly modified protocol for saliva samples. Saliva-based IgG testing had 30% sensitivity and 100% specificity, with a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 50%. Saliva-based IgM/IgA testing had 13.2% sensitivity and 100% specificity, with a PPV of 100% and an NPV of 28.3%. Blood and saliva IgG values were positively correlated. Saliva currently has limited diagnostic value for COVID-19 testing, at least for mild disease. Nevertheless, the significant positive correlation between blood and saliva IgG titers indicates that saliva might be a complementary biofluid for assessing systemic antibody responses to the virus, especially if the assay is further optimized across the full disease spectrum.

The Polk COVID-19 and Flu Response clinical trial: COVID-19 antibody positivity higher in Black EMS workers

This study reports on a countywide assessment of COVID-19 positivity among emergency medical services workers. Participants completed a short survey of demographic factors and co-morbidities prior to obtaining COVID-19 and influenza testing to analyze the prevalence of these two respiratory viruses that EMS workers, being the first on the scene, are at special risk for, especially in the early days of the pandemic. A total of 7% had a positive COVID-19 antibody test. Although Black EMS personnel only comprised 9% of the cohort, they were significantly more likely to test positive for COVID-19 (P=0.0012). Black race remained a statistically significant predictor in a multivariate model that included the age, sex, BMI, number of hours of direct patient contact, whether the medic was symptomatic, presence of co-morbidities and whether or not the medic had received a flu shot prior (P=0.0008, 95% CI 0.0621-0.2354). This clinical trial (NCT04682132) ) was registered at clinicaltrials.gov, a resource provided by the U.S. National Library of Medicine.

COVID-19-induced Neonatal Acute Aortic Thrombosis

Abstract Venous thromboembolism is a well-recognized, common complication of a severe COVID-19 disease. Arterial thrombosis is a less known complication, now being reported increasingly, mostly in the form of myocardial infarction and stroke, but acute aortic occlusion is infrequent. Neonatal acute aortic thrombosis as a sequelae of COVID-19 disease has far uncommon incidence with no literature-based evidence till date. A 10-day-old male child presented to the emergency department with informant being his mother with complaints of black discoloration of his right foot for 4 days noticed first on his toes. No history of trauma, no history of fever, and no history of umbilical artery catheterization at birth was noted. Birth history-full term normal vaginal delivery, small for gestational age baby, cried immediately after birth, birth weight – 2.45 kg with no additional birth events. No history of neonatal intensive care unit stay, immunized at birth. Baby was 3rd by order of birth with no congenital anomalies noted in previous siblings. On examination, the baby was alert, afebrile, heart rate – 138/min, blood pressure – 90/60 mmHg, and SpO2 98% on room air. Local examination of the right lower limb revealed black discoloration of the right lower limb from toes up to mid-calf, CRT-delayed in the right thigh (7 s), right femoral pulsations absent, left lower limb – pink, warm, CRT – 6 s, feeble pulsations of left femoral artery and popliteal artery, absent pulsations of left anterior tibial artery, and posterior tibial artery. A Doppler study revealed the presence of partial lumen occluding thrombus (hyperechoic) in abdominal aorta below the level of renal arteries, absent flow in right lower limb, and monophasic flow in left femoral artery. A prothtrombotic screen was performed and COVID-19 antibody test was found to be positive. A systemic thrombolysis with injection reteplase was performed which showed mild improvement in circulation with propagation of clot up to origin of superior mesentric artery on a Doppler scan. An abdominal aortic embolectomy was performed, with retrieval of a long segment thrombus from distal abdominal aorta and bilateral femoral arteries following good proximal inflow and good distal backflow. Bilateral limb perfusion improved postoperatively though the gangrenous right lower limb could not be saved and a right below knee amputation was performed for the same. This case adds to the growing list of potential sites and consequences of thrombosis in COVID-19 infection. We speculate that this case of aortic thrombosis was a result of direct COVID-19-induced vascular damage in the context of a hypercoagulable state with a possibility of vertical transmission of the disease.

COVID-19 Antibody Testing in Healthcare Workers in Arkansas

COVID-19 Antibody Testing in Healthcare Workers in Arkansas

Clinical Utility of SARS-CoV-2 Antibody Testing

SARS-CoV-2 antibody assay is a test that checks whether an antibody against the SARS-CoV-2 virus has been formed in the blood after SARS-CoV-2 infection or vaccination. SARS-CoV-2 antibody is detected 1–2 weeks after infection, and antibodies are produced in more than 90% of infected patients. The duration for the formation of antibodies differs by individual and by type of antibody. In the case of IgG, it is at least several months or longer, and the relationship between antibodies and immunity is being studied. As test methods,enzyme-linked immunosorbent assay (ELISA), chemiluminescence immunoassay (CIA), immunochromatographic assay, and neutralizing antibody assay have been developed and used. The target antibody to be detected differs depending on the type of recombinant antigen and the type of secondary antibody in reagents. Many kinds of commercialized SARS-CoV-2 antibody assays are currently being developed, and the S (spike) protein, N (nucleocapsid) protein, S1 or RBD (receptor binding domain) part of the S protein, and a mixture of these antigens are used as recombinant antigens of reagents. IgG, IgM, IgA, or total immunoglobulin antibodies in patients’ blood that react with these reagent antigens are detected. In this review, the types and performance of SARS-CoV-2 antibody tests and the guidelines for COVID-19 antibody tests published domestically and abroad were investigated.

Assessment of antibody dynamics and neutralizing activity using serological assay after SARS-CoV-2 infection and vaccination.

The COVID-19 antibody test was developed to investigate the humoral immune response to SARS-CoV-2 infection. In this study, we examined whether S antibody titers measured using the anti-SARS-CoV-2 IgG II Quant assay (S-IgG), a high-throughput test method, reflects the neutralizing capacity acquired after SARS-CoV-2 infection or vaccination. To assess the antibody dynamics and neutralizing potency, we utilized a total of 457 serum samples from 253 individuals: 325 samples from 128 COVID-19 patients including 136 samples from 29 severe/critical cases (Group S), 155 samples from 71 mild/moderate cases (Group M), and 132 samples from 132 health care workers (HCWs) who have received 2 doses of the BNT162b2 vaccinations. The authentic virus neutralization assay, the surrogate virus neutralizing antibody test (sVNT), and the Anti-N SARS-CoV-2 IgG assay (N-IgG) have been performed along with the S-IgG. The S-IgG correlated well with the neutralizing activity detected by the authentic virus neutralization assay (0.8904. of Spearman's rho value, p < 0.0001) and sVNT (0.9206. of Spearman's rho value, p < 0.0001). However, 4 samples (2.3%) of S-IgG and 8 samples (4.5%) of sVNT were inconsistent with negative results for neutralizing activity of the authentic virus neutralization assay. The kinetics of the SARS-CoV-2 neutralizing antibodies and anti-S IgG in severe cases were faster than the mild cases. All the HCWs elicited anti-S IgG titer after the second vaccination. However, the HCWs with history of COVID-19 or positive N-IgG elicited higher anti-S IgG titers than those who did not have it previously. Furthermore, it is difficult to predict the risk of breakthrough infection from anti-S IgG or sVNT antibody titers in HCWs after the second vaccination. Our data shows that the use of anti-S IgG titers as direct quantitative markers of neutralizing capacity is limited. Thus, antibody tests should be carefully interpreted when used as serological markers for diagnosis, treatment, and prophylaxis of COVID-19.

Performance of commercial SARS-CoV-2 wild-type and Omicron BA.1 antibody assays compared with pseudovirus neutralization tests.

Commercially available ELISA-based antibody tests are used to approximate vaccination success against SARS-CoV-2 in at-risk patients, but it is unclear whether they correlate with neutralization of the Omicron variant. 269 serum samples of a cohort of 44 non-immunosuppressed participants and 65 MTX-treated rheumatic patients taken before and after COVID-19 booster vaccinations were measured using COVID-19 antibody testing systems with wild-type and Omicron BA.1 antigens developed by three different manufacturers (surrogate virus neutralization test cPass, and binding antibody tests QuantiVac and SeraSpot), as well as with a pseudovirus neutralization test (pVNT). The pVNT was considered the gold standard for determining the presence and level of anti-SARS-CoV-2 antibodies. All three wild-type ELISAs showed excellent test performance compared with wild-type neutralization in pVNT. However, out of 56 samples without Omicron BA.1 neutralization in pVNT, 71.4% showed positive results in at least one and 28.6% in all three wild-type ELISAs at the manufacturer-defined cut-offs. Omicron ELISAs showed either decreased specificity (57.1% and 55.4% for binding ELISAs) or sensitivity (51.2% in cPass) compared to Omicron neutralization in pVNT. The proportion of any false positive results among all samples decreased from 26.5% before to 3.2% after booster vaccination, however binding antibody test specificities remained below 70%. We found a poorer test performance of new Omicron antibody test systems compared to wild-type tests in detecting neutralizing antibodies against the corresponding SARS-CoV-2 variants. Decisions for booster vaccination or passive immunization of at-risk patients should not be based solely on antibody test results.

Subsequent COVID-19 Prophylaxis in COVID-19 Associated Glomerulopathies.

Successful vaccination has been the decisive factor in the overall decline of SARS-CoV2 infection related morbidity and mortality. However, global effects of the COVID-19 pandemic are ongoing, with reports of glomerular disease occurring in relation to both infection and vaccination. A particular rise in anti-GBM disease has been identified. Information is still emerging regarding the optimal management of such cases. We reviewed anti-GBM antibody detection rates at our test center over the past 5 years. We followed three patients with biopsy confirmed glomerular disease temporally related to COVID-19 vaccination. Each patient proceeded to receive subsequent COVID-19 vaccination as per immunologist recommendations. Further assessment included COVID-19 antibody testing in each case. A three-fold increase in significant anti-GBM antibody results noted at our center was associated with COVID infection in 10% of cases, and COVID vaccination in 25% of cases. We demonstrated that subsequent vaccination did not appear to lead to adverse effects including relapse in our three cases of COVID-19 vaccine-associated GN. We also identified positive COVID-19 antibody levels in two out of three cases, despite immunosuppression. We report a rise in anti-GBM antibody disease incidence. Our small study suggests that COVID-19 antibody testing can help determine COVID prophylaxis requirements, and subsequent vaccination with an alternative vaccine type appears safe.

Rapidly adaptable automated interpretation of point-of-care COVID-19 diagnostics

BackgroundPoint-of-care diagnostic devices, such as lateral-flow assays, are becoming widely used by the public. However, efforts to ensure correct assay operation and result interpretation rely on hardware that cannot be easily scaled or image processing approaches requiring large training datasets, necessitating large numbers of tests and expert labeling with validated specimens for every new test kit format.MethodsWe developed a software architecture called AutoAdapt POC that integrates automated membrane extraction, self-supervised learning, and few-shot learning to automate the interpretation of POC diagnostic tests using smartphone cameras in a scalable manner. A base model pre-trained on a single LFA kit is adapted to five different COVID-19 tests (three antigen, two antibody) using just 20 labeled images.ResultsHere we show AutoAdapt POC to yield 99% to 100% accuracy over 726 tests (350 positive, 376 negative). In a COVID-19 drive-through study with 74 untrained users self-testing, 98% found image collection easy, and the rapidly adapted models achieved classification accuracies of 100% on both COVID-19 antigen and antibody test kits. Compared with traditional visual interpretation on 105 test kit results, the algorithm correctly identified 100% of images; without a false negative as interpreted by experts. Finally, compared to a traditional convolutional neural network trained on an HIV test kit, the algorithm showed high accuracy while requiring only 1/50th of the training images.ConclusionsThe study demonstrates how rapid domain adaptation in machine learning can provide quality assurance, linkage to care, and public health tracking for untrained users across diverse POC diagnostic tests.

Clinical course and native antibody development after COVID-19 infection in 50 pediatric oncology patients.

10063 Background: Pediatric oncology patients are at higher risk for severe COVID-19 infection compared to healthy children. However, pediatric cancer patients appear to be at lower risk of severe infection compared to adults with cancer. Lower rates of native antibody development have been seen in adults with hematologic malignancies particularly those with a history of transplant or anti-CD20 therapy. Data on the clinical characteristics of COVID-19 and antibody development after infection in children with cancer are limited. This study aims to describe the clinical manifestations of COVID-19 infection in pediatric caner patients, identify variables associated with severe infection, and evaluate native antibody development. Methods: REsearch on COVid-19 in Oncology to Inform Recovery and Mitigate Future Risk (RECOVOR) is an IRB approved institutional cohort study at Dana-Farber Cancer Institute. Pediatric patients with cancer who had COVID-19 are eligible 1-12 months following qtPCR confirmed infection. Blood samples are collected at 2 timepoints (3-12 months after COVID-19 infection and 6-9 months later) and undergo research analysis as well as clinical Anti-SARS-COV-2 (antibody response only to native infection) testing. Results: We report on the first 50 patients enrolled on the RECOVOR study from March 2021 to Dececember 2022 (COVID infection between March 2020 and November 2022). In this cohort, 56% (28/50) were male, 60% (30/50) had hematologic malignancies, 28% (14/50) had solid tumors, and 12% (6/50) had CNS tumors. Median patient age was 10.4 years (range 1-22 years). Most patients (86%; 43/50) were on active cancer treatment, of which 76% (33/43) had modifications in cancer-directed therapy due to COVID-19 infection. 76% of patients with COVID-19 were symptomatic and 26% (13/50) were hospitalized for COVID-19 symptoms. COVID-19 directed treatments were administered to 44% (22/50) of patients, most commonly antivirals (n = 12), monoclonal antibodies (n = 9), steroids (n = 3) and IVIG (n = 2). Native COVID-19 antibody testing 3-12 months post infection was performed for 88% (44/50) of patients, with 64% (28/44) seropositive at a median time of 5 months post-infection. Repeat antibody testing at timepoint 2 was available for 20 patients, with 14/14 remaining seropositive, 6/7 remaining seronegative, and 1 converting from seronegative to seropositive. Conclusions: The clinical characteristics of COVID-19 seen in this cohort of 50 pediatric oncology patients is consistent with prior reports, highlighting a high risk of hospitalization in this population. This study is the first to evaluate COVID-19 antibody development in pediatric cancer patients and showed that 63% of patients developed antibodies. Pediatric enrollment is ongoing and additional analyses are underway to assess factors associated with severe COVID-19 infection and/or associated antibody response.

How did the COVID-19 pandemic affect the management of patients with cancer? What is the impact of anti-cancer medications on the immune response to the COVID-19 vaccinations?.

e24193 Background: This study had two objectives: To assess the impact of the COVID-19 pandemic on cancer patients’ management. To determine the impact of cancer types and anti-cancer medications on the immune response to COVID-19 vaccinations. Methods: Cancer patients at the Moncton Hospital, Oncology/Hematology Clinic, were invited to voluntarily complete a survey about the date of their cancer diagnosis, treatment, the impact of the COVID-19 pandemic on their health, and to complete a prepared list of possible side effects that they experienced after receiving any of the COVID-19 vaccines. Participants, who had received at least two doses of any COVID-19 vaccine, were given the option to consent to a sub-study to provide a blood sample to check their antibody response to the COVID-19 vaccination. Blood samples were collected at least 4 weeks after the second dose of a primary vaccine series, or at least 2 weeks after any booster dose. Samples were sent to the Dr. Georges-L.-Dumont University Hospital lab to be analyzed. Data was collected regarding the type of treatment (chemotherapy, immunotherapy, targeted therapy, hormonal therapy, radiation therapy, or a combination of these therapies). Analysis of the data was done using SPSS program. Results: 178 patients completed the survey. 117 patients had solid tumors, and 61 had a hematological malignancy. The mean age was 65.75 (range 31-90) years and 45.5% were males. 62.3% either had a high school diploma or a graduate degree. When asked if their anxiety about their health increased due to the pandemic, 57.8% reported that their anxiety level has moderately or somewhat increased. Similarly, around 70% responded that their stress levels moderately or somewhat increased due to the pandemic. Only 7.3% of patients mentioned that they had delays in diagnosis, and only 2.8% had changes in their treatment, however, around 30% had their appointments changed into phone appointments as a result of the pandemic. Only 4% reported a loss of job due to the pandemic, and 11.2% reported financial stress. Cross tabulations were done between type of cancer and results of the COVID-19 antibody test and type of treatment and results of the COVID-19 antibody test. Results showed that the type of treatment that the patient was receiving has no impact on the production of COVID-19 antibodies. However, antibodies after COVID-19 vaccination were not detected in 20.5% (10/49) of patients with hematological malignancies compared to 3.6% (3/82) of patients with solid tumors. This difference was statistically significant (p = 0.001). Conclusions: The pandemic affected Cancer patients in terms of increasing their anxiety and stress levels. The production of antibodies after COVID-19 vaccinations was significantly decreased in patients with hematological malignancies.

The Frequency and Risk Factors for COVID-19 Infection among Healthcare Workers in a Large-Scale University Teaching Hospital: A Case Control Study

Objective: This study aims to find out the frequency and risk factors responsible for COVID-19 infection among healthcare workers in a large-scale university teaching hospital. Methods: This case-control study was conducted on 185 healthcare workers sampled from the database of 1309 participants maintained at Dr. Ruth K. M. Pfau Civil Hospital, Karachi. Both the cases and controls were derived from the hospital’s database of COVID-19 Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) and COVID-19 antibody tests performed on the said population. The participants included were physicians working in the hospital. They were grouped into cases and controls based on the positive diagnostic tests. We administered a simple structured questionnaire over the telephone and face to face for the interview. Statistical analyses were performed on IBM SPSS version 25. Results: The mean age of cases was significantly different than controls [cases (32.7±9.9) vs controls (38.8±10.6), p-value=0.002]. More cases 29/37 (78.3%) were working at a single setting compared to controls 54/148 (36.5%) (P-value &lt;0.001). The use of Personal Protective Equipment (PPE), exposure to COVID-19 patients and experiencing symptoms also had statistical significance with the odds of infection (p-value &lt;0.05). Conclusion: This study concludes that younger age, exposure to a known COVID-19 patient and longer duration of exposure among the hospital physicians is associated with positive COVID-19 results. Therefore, it is imperative that adequate measures be undertaken to limit the exposure to COVID-19 patients in this age group.

COVID-19 related acute necrotizing encephalopathy presenting in the early postoperative period

Besides respiratory and gastrointestinal symptoms, SARS-CoV-2 also has potential neurotropic effects. Acute hemorrhagic necrotizing encephalopathy is a rare complication of Covid-19. This article presents a case of an 81-year-old female, fully vaccinated, who underwent laparoscopic transhiatal esophagectomy due to gastroesophageal junction cancer. In the early postoperative period, the patient developed persistent fever accompanied by acute quadriplegia, impaired consciousness, and no signs of respiratory distress. Imaging with Computed Tomography and Magnetic Resonance revealed multiple bilateral lesions both in gray and white matter, as well as pulmonary embolism. Covid-19 infection was added to the differential diagnosis three weeks later, after other possible causes were excluded. The molecular test obtained at that time for coronavirus was negative. However, the high clinical suspicion index led to Covid-19 antibody testing (IgG and IgΑ), which confirmed the diagnosis. The patient was treated with corticosteroids with noticeable clinical improvement. She was discharged to a rehabilitation center. Six months later, the patient was in good general condition, although a neurological deficit was still present. This case indicates the significance of a high clinical suspicion index, based on a combination of clinical manifestations and neuroimaging, and the confirmation of the diagnosis with molecular and antibody testing. Constant awareness of a possible Covid-19 infection among hospitalized patients is mandatory.

EVALUATION OF SARS COVID -19 ANTIBODY STATUS OF INDIVIDUALS IN POST COVID OUT PATIENT DEPARTMENT OF TERTIARY CARE HOSPITAL OF CENTRAL INDIA

Introduction: COVID-19 is caused by the SARS-CoV-2 virus and it was rst identied after an outbreak of Pneumonia in Wuhan, China in December 2019. SARS-CoV-2 is an enveloped, positive-strand RNA virus. Several risk factors are associated with the complications of COVID-19. The Immune system produces IgM, IgG, and Neutralizing antibodies which can block the virus from entering cells. Long term humoral response post COVID-19 infection is still not clearly known. Studies related to complete course of IgG antibody in COVID-19 infection are very sparse. The present study was therefore conducted to evaluate SARS COVID-2 COVID-19 antibody status of individuals in post COVID-19 OPD in Central India's population at our tertiary care hospital. Material and methods: A prospective study was conducted in the Department of Microbiology of a tertiary health care centre for a period of one year from January 2021 to December 2022. The cases included in the study were individuals attending post COVID OPD and giving written informed consent for COVID-19 Antibody Test (IgG). Cases were studied in relation to their age, sex, relevant clinical history, relevant clinical comorbidities, status of COVID report with date. Blood samples from the study subjects were tested for the presence of IgG antibody. Results: IgG antibody is positive in maximum cases in 0-6 months, followed by 7-12 months, then in 13-18 months and then in 19-24 months. IgG antibody was not detected in cases where the time duration between positive COVID-19 test and IgG test was more than 18 months. Conclusion: Our study could be a very important footstep towards understanding the long term humoral response in COVID-19 infection

PAWG pilot study on quantification of SARS-CoV-2 monoclonal antibody - Part 2

Main textUnder the auspices of the Protein Analysis Working Group (PAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a pilot study, CCQM-P216, was coordinated by the Chinese National Institute of Metrology (NIM), National Research Council of Canada (NRC) and the Bureau International des Poids et Mesures (BIPM).The global coronavirus pandemic has also led to increased focus on antibody quantitation methods. IgG are among the immunoglobulins produced by the immune system to provide protection against SARS-CoV-2. Anti-SARS-CoV-2 IgG can therefore be detected in samples from affected patients. Antibody tests can show whether a person has been exposed to SARS-CoV-2, and whether or not they potentially show lasting immunity to the disease. With the constant spread of the virus and the high pressure of re-opening economies, antibody testing played a critical role in the fight against COVID-19 by helping healthcare professionals to identify individuals who have developed an immune response, either via vaccination or exposure to the virus. Many countries have launched large-scale antibody testing for COVID-19. The development of measurement standards for the antibody detection of SARS-CoV-2 is critically important to deal with the challenges of the COVID-19 pandemic. In this study, the SARS-CoV-2 monoclonal antibody is being used as a model system to build capacity in methods that can be used in antibody quantification.The purpose of this pilot study was to develop measurement capabilities for larger proteins using a recombinant humanized IgG monoclonal antibody against Spike glycoprotein of SARS-CoV-2 (Anti-S IgG mAb) in solution. A Final Report on the first round of CCQM-P216 PAWG Pilot Study on Quantification of SARS-CoV-2 Monoclonal Antibody - Part 1 focusing on the assessment of both mass fraction determinations of different AAs in the material and mass fraction determinations of proteotypic peptides belonging to the constant region of the mAb has already been published in Metrologia. The present Final Report on the second round of CCQM-P216 - Part 2 was designed to investigate optional methods for the characterization of Anti-S IgG mAb in solution for the assessment of size heterogeneity purity determinations, mass fraction measurements of SARS-CoV-2 monoclonal antibody in the material by UV-VIS spectrophotometry, mass fraction measurements of proteotypic peptides belonging to the variable region of the mAb and mass fraction measurements of monomeric mAb in the material. Six Metrology Institutes or Designated Institutes and the BIPM participated in the second phase of the pilot study (Part 2).Acceptable agreement between all laboratories was for the assessment of size heterogeneity of the anti-S IgG mAb material. For example, a reference value with its corresponding expanded uncertainties of (99.48 ± 0.49) % has been obtained for the monomer. Good between laboratories for UV-VIS spectrophotometric analysis at a pre-agreed wavelength of 280 nm was obtained with individual relative expanded uncertainties from 2.8 % to 15.5 % and a mass concentration reference value and corresponding expanded uncertainty of (500.8 ± 15.4) mg/L.Mass fraction assignments of the target proteotypic peptide YSPSFQGQVTISADK in the variable region of the anti-S IgG mAb material by NIM and BIPM resulted in a reference value and corresponding expanded uncertainty of (9.8 ± 2.0) mg/kg.Both NIM and BIPM have provided estimates for the mass fraction of monomeric mAb in the material with individual relative expanded uncertainties of 4.3 % and 4.1 %, respectively. A mass fraction reference value and corresponding expanded uncertainty of (411 ± 88) mg/kg was calculated by applying an 'excess-variance' approach for the monomeric mAb mass fraction.In addition, a post-hoc assessment of the monomeric mAb mass fraction from the subset of that produced both amino acid and proteotypic peptide-based mass fraction results and SEC measurements during the 1st and present study round provided more detailed information. A reference value and its expanded uncertainty for the mass fraction of monomeric mAb in the anti-S IgG mAb material was calculated to be (434.3 ± 11.9) mg/kg applying an 'excess-variance' approach.The level of agreement was not significantly poorer than that achieved in previous studies with smaller or less complex proteins. The two-stage pilot study was a big step forward to build and improve capacity within NMIs/DIs to undertake future key comparisons in the field of mass fraction determinations of antibodies and other large proteins.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Dried blood spots are a valid alternative to venipuncture for COVID-19 antibody testing

BackgroundSerologic analysis is an important tool towards assessing the humoral response to COVID-19 infection and vaccination. Numerous serologic tests and platforms are currently available to support this line of testing. Two broad antibody testing categories are point-of-care lateral flow immunoassays and semi-quantitative immunoassays performed in clinical laboratories, which typically require blood collected from a finger-stick and a standard venipuncture blood draw, respectively. This study evaluated the use of dried blood spot (DBS) collections as a sample source for COVID-19 antibody testing using an automated clinical laboratory test system. MethodsTwo hundred and ninety-four participants in the BLAST COVID-19 seroprevalence study (NCT04349202) were recruited at the time of a scheduled blood draw to have an additional sample taken via finger stick as a DBS collection. Using the EUROIMMUN assay to assess SARS-CoV-2 anti-spike IgG status, DBS specimens were tested on 7, 14, 21, and 28 days post- collection and compared to the reference serum sample obtained from a blood draw for the BLAST COVID-19 study. ResultsSARS-CoV-2 anti-spike IgG status from DBS collections demonstrated high concordance with serum across all time points (7–28 days). However, the semi-quantitative value from DBS collections was lower on average than that from serum, resulting in increased uncertainty around the equivocal-to-positive analytical decision point. ConclusionsDBS collections can be substituted for venipuncture when assaying for COVID-19 IgG antibody, with samples being stable for at least 28 days at room temperature. Finger-stick sampling can therefore be advantageous for testing large populations for SARS-CoV-2 antibodies without the need for phlebotomists or immediate processing of samples. We have high confidence in serostaus determination from DBS collections, although the reduced semi-quantitative value may cause some low-level positives to fall into the equivocal or even negative range.

Integrative Effects between a Bubble and Seal Program and Workers’ Compliance to Health Advice on Successful COVID-19 Transmission Control in a Factory in Southern Thailand

Applying health measures to prevent COVID-19 transmission caused disruption of businesses. A practical plan to balance public health and business sustainability during the pandemic was needed. Herein, we describe a "Bubble and Seal" (B&S) program implemented in a frozen seafood factory in southern Thailand. We enrolled 1539 workers who lived in the factory dormitories. First, the workers who had a high fatality risk were triaged by RT-PCR tests, quarantined and treated if they had COVID-19. Newly diagnosed or suspected COVID-19 workers underwent the same practices. The non-quarantined workers were regulated to work and live in their groups without contact across the groups. Workers' personal hygiene and preventive measures were strongly stressed. Between the 6th and 9th weeks of the program, the post-COVID-19 infection status (PCIS) of all participants was evaluated by mass COVID-19 antibody or RT-PCR tests. Finally, 91.8% of the workers showed positive PCIS, which was above the number required for program exit. Although no workers had received a vaccination, there was only one case of severe COVID-19 pneumonia, and no evidence of COVID-19 spreading to the surrounding communities. Implementation of the B&S program and workers' adherence to health advice was the key to this success.