Pre-pandemic Controls Research Articles

Salivary and serum IgA and IgG responses to SARS-CoV-2-spike protein following SARS-CoV-2 infection and after immunization with COVID-19 vaccines.

Background: Secretory immunoglobulin A (sIgA) plays an important role in antiviral protective immunity. Although salivary testing has been used for many viral infections, including severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS), its use has not yet been well established with the SARS coronavirus 2 (SARS-CoV-2). Quantification of salivary IgA and IgG antibodies can elucidate mucosal and systemic immune responses after natural infection or vaccination. Here, we report the development and validation of a rapid enzyme-linked immunosorbent assay (ELISA) for anti-SARS-CoV-2 salivary IgA and serum IgG antibodies, and present quantitative results for immunized subjects both prior to or following COVID-19 infections. Objective: Total and serum SARS-CoV-2 spike-specific IgG responses were compared with salivary spike-specific IgA and IgG responses in samples obtained from patients recently infected with SARS-CoV-2 and from subjects recently immunized with COVID-19 vaccines. Methods: A total of 52 paired saliva and serum samples were collected from 26 study participants: 7 subjects after COVID-19 infection and 19 subjects who were uninfected. The ELISA results from these samples were compared with five prepandemic control serum samples. Total IgG and SARS-CoV-2 spike-specific IgG in the serum samples from the subjects who were infected and vaccinated were also measured in a commercial laboratory with an enzyme immunoassay. Results: A wide variation in antibody responses was seen in salivary and serum samples measured by both methods. Three groups of serum total and IgG spike-specific SARS-CoV-2 antibody responses were observed: (1) low, (2) intermediate, and (3) high antibody responders. A correlational analysis of salivary IgA (sIgA) responses with serum IgG concentrations showed a statistical correlation in the low and intermediate antibody responder groups but not in the high group (which we believe was a result of saturation). Conclusion: These preliminary findings suggest measuring salivary and serum IgG and IgA merit further investigation as markers of current or recent SARS-CoV-2 infections.

Early-stage COVID-19 pandemic observations on pulmonary embolism using nationwide multi-institutional data harvesting

We introduce a multi-institutional data harvesting (MIDH) method for longitudinal observation of medical imaging utilization and reporting. By tracking both large-scale utilization and clinical imaging results data, the MIDH approach is targeted at measuring surrogates for important disease-related observational quantities over time. To quantitatively investigate its clinical applicability, we performed a retrospective multi-institutional study encompassing 13 healthcare systems throughout the United States before and after the 2020 COVID-19 pandemic. Using repurposed software infrastructure of a commercial AI-based image analysis service, we harvested data on medical imaging service requests and radiology reports for 40,037 computed tomography pulmonary angiograms (CTPA) to evaluate for pulmonary embolism (PE). Specifically, we compared two 70-day observational periods, namely (i) a pre-pandemic control period from 11/25/2019 through 2/2/2020, and (ii) a period during the early COVID-19 pandemic from 3/8/2020 through 5/16/2020. Natural language processing (NLP) on final radiology reports served as the ground truth for identifying positive PE cases, where we found an NLP accuracy of 98% for classifying radiology reports as positive or negative for PE based on a manual review of 2,400 radiology reports. Fewer CTPA exams were performed during the early COVID-19 pandemic than during the pre-pandemic period (9806 vs. 12,106). However, the PE positivity rate was significantly higher (11.6 vs. 9.9%, p < 10−4) with an excess of 92 PE cases during the early COVID-19 outbreak, i.e., ~1.3 daily PE cases more than statistically expected. Our results suggest that MIDH can contribute value as an exploratory tool, aiming at a better understanding of pandemic-related effects on healthcare.

Reliability of Acoustic Measures in Dysphonic Patients With Glottic Insufficiency and Healthy Population: A COVID-19 Perspective

ObjectivesThe COVID-19 pandemic has affected the voice assessment protocols for dysphonic patients. In this study, we compared the changes in acoustic measures of the healthy population as well as dysphonic patients due to glottic insufficiency between the pandemic period requiring face masks and the prepandemic period when the masks were not essential. The clinical reliability of the acoustic measures with and without face masks was explored.MethodsA total of 120 patients (age = 42.3 ± 11.9 yrs) with glottic insufficiencies such as UVFP and sulcus vocalis and 40 healthy population (age = 40.5 ± 11.2 yrs) cohorts were enrolled during the pandemic period. Age- and gender-matched 120 patients and 40 healthy population cohorts who underwent voice assessment without face masks before the pandemic were enrolled as prepandemic controls. Acoustic measures and overall severity estimates of vowel and speech samples were compared, which included cepstral peak prominence (CPP), L/H spectral ratio (SR), their standard deviations, F0, jitter percent (Jitt), shimmer percent (Shim), noise-to-harmonic ratio (NHR), Cepstral Spectral Index of Dysphonia (CSID), and Acoustic Psychometric Severity Index of Dysphonia.ResultsBoth patients and healthy cohorts showed higher SRv and SRs but lower CSIDv during the pandemic compared to the prepandemic period. F0 of the healthy male controls during the pandemic was higher than during the prepandemic periods, while the CSIDs was lower for the pandemic period. The pandemic patient cohort showed lower σSRs compared to the prepandemic patient cohort. When the acoustic measures of patients were compared to the healthy population cohort, the patient cohort showed lower CPP and σCPPs, while higher σCPPv, Jitt, Shim, and NHR during both pandemic and prepandemic period. Overall, the area under the curve of the acoustic measures and overall severity estimates was similar between the mask and non-mask groups, although the AUC of the SR measures was poor.ConclusionsWearing face masks during the pandemic did not compromise the overall reliability of the acoustic analysis in patients with glottic insufficiency, suggesting the current protocol of acoustic analysis can be carried out reliably while wearing a mask to ensure safety in the pandemic era.

Metallomic and Untargeted Metabolomic Signatures of Human Milk from SARS-CoV-2 Positive Mothers.

ScopeLack of information about the impact of maternal severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection on the elemental and metabolomic profile of human milk (HM).Methods and resultsAn observational study on HM from mothers with COVID‐19 is conducted including a prepandemic control group. Maternal–infant clinical records and symptomatology are recorded. The absolute quantification of elements and untargeted relative metabolomic profiles are determined by inductively coupled plasma mass spectrometry and gas chromatography coupled to mass spectrometry, respectively. Associations of HM SARS‐CoV‐2 antibodies with elemental and metabolomic profiles are studied. COVID‐19 has a significant impact on HM composition. COVID‐19 reduces the concentrations of Fe, Cu, Se, Ni, V, and Aluminium (Al) and increases Zn compared to prepandemic control samples. A total of 18 individual metabolites including amino acids, peptides, fatty acids and conjugates, purines and derivatives, alcohols, and polyols are significantly different in HM from SARS‐CoV‐2 positive mothers. Aminoacyl‐tRNA biosynthesis, phenylalanine, tyrosine and tryptophan biosynthesis, phenylalanine, and linoleic acid pathways are significantly altered. Differences are obtained depending on COVID‐19 symptomatic and asymptomatic status.ConclusionsThis study provides unique insights about the impact of maternal SARS‐CoV‐2 infection on the elemental and metabolomic profiles of HM that warrants further research due the potential implications for infant health.

Can COVID-19 worsen racial disparities in breast cancer screening and diagnosis?

BackgroundHealth disparities among minority groups, especially African Americans, can limit their access to quality medical care and lead to disproportionate medical management and disease outcomes. The aim of this study was to compare the COVID-19-related change in mammogram volumes and cancer detection at two affiliated academic breast centers, one that serves a predominantly African American patient population and one that serves a predominantly non-African American patient population.Materials and methodsFor the purpose of anonymity, racial demographics were collected and the center with a higher African American patient population was designated as institution A, while the center with a higher non-African American patient population was designated as institution B. Careful selection of the two breast centers was instituted in order to limit the impact of potential confounders other than race.An Institutional Review Board (IRB) exemption was obtained and two Mammography Quality Standards Act (MQSA) reports were generated; one for March 2020 through September 2020, during the height of the COVID-19 pandemic, and one for March 2019 through September 2019 to serve as the pre-pandemic control group. The i2b2 Query Analysis Tool® was used to obtain racial demographic data and compare the percent change in screening and diagnostic mammograms, image-guided biopsies, total cancers diagnosed by imaging, and percent of minimal cancers for both institutions.ResultsScreening mammograms and breast cancer detection decreased in 2020 compared to 2019 at both institutions. However, the percent change from 2019 to 2020 was greater at institution A than at institution B. Percent minimal cancers, an indicator of early-stage breast cancer also decreased more drastically at institution A than at institution B. Interestingly, the total number of diagnostic exams and image-guided biopsies increased in 2020 at institution B, whereas both decreased at institution A.ConclusionThe COVID-19 pandemic may lead to worsening racial disparities in breast cancer screening. In an effort to narrow future disparity, it is crucial for radiologists and other health care providers to be aware of this inequality and educate all women on the importance of obtaining routine screening mammography. More studies are needed.

Antibodies targeting conserved non-canonical antigens and endemic coronaviruses associate with favorable outcomes in severe COVID-19.

While there have been extensive analyses characterizing cellular and humoral responses across the severity spectrum in COVID-19, outcome predictors within severe COVID-19 remain less comprehensively elucidated. Furthermore, properties of antibodies (Abs) directed against viral antigens beyond spike and their associations with disease outcomes remain poorly defined. We perform deep molecular profiling of Abs directed against a wide range of antigenic specificities in severe COVID-19 patients. The profiles included canonical (spike [S], receptor-binding domain [RBD], and nucleocapsid [N]) and non-canonical (orf3a, orf8, nsp3, nsp13, and membrane [M]) antigenic specificities. Notably, multivariate Ab profiles directed against canonical or non-canonical antigens are equally discriminative of survival in severe COVID-19. Intriguingly, pre-pandemic healthy controls have cross-reactive Abs directed against nsp13, a protein conserved across coronaviruses. Consistent with these findings, a model built on Ab profiles for endemic coronavirus antigens also predicts COVID-19 outcome. Our results suggest the importance of studying Abs targeting non-canonical severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and endemic coronavirus antigens in COVID-19.

Maternal psychological distress during the COVID-19 pandemic and structural changes of the human fetal brain

BackgroundElevated maternal psychological distress during pregnancy is linked to adverse outcomes in offspring. The potential effects of intensified levels of maternal distress during the COVID-19 pandemic on the developing fetal brain are currently unknown.MethodsWe prospectively enrolled 202 pregnant women: 65 without known COVID-19 exposures during the pandemic who underwent 92 fetal MRI scans, and 137 pre-pandemic controls who had 182 MRI scans. Multi-plane, multi-phase single shot fast spin echo T2-weighted images were acquired on a GE 1.5 T MRI Scanner. Volumes of six brain tissue types were calculated. Cortical folding measures, including brain surface area, local gyrification index, and sulcal depth were determined. At each MRI scan, maternal distress was assessed using validated stress, anxiety, and depression scales. Generalized estimating equations were utilized to compare maternal distress measures, brain volume and cortical folding differences between pandemic and pre-pandemic cohorts.ResultsStress and depression scores are significantly higher in the pandemic cohort, compared to the pre-pandemic cohort. Fetal white matter, hippocampal, and cerebellar volumes are decreased in the pandemic cohort. Cortical surface area and local gyrification index are also decreased in all four lobes, while sulcal depth is lower in the frontal, parietal, and occipital lobes in the pandemic cohort, indicating delayed brain gyrification.ConclusionsWe report impaired fetal brain growth and delayed cerebral cortical gyrification in COVID-19 pandemic era pregnancies, in the setting of heightened maternal psychological distress. The potential long-term neurodevelopmental consequences of altered fetal brain development in COVID-era pregnancies merit further study.

Viral Antigen and Inflammatory Biomarkers in Cerebrospinal Fluid in Patients With COVID-19 Infection and Neurologic Symptoms Compared With Control Participants Without Infection or Neurologic Symptoms

Neurologic symptoms are common in COVID-19, but the central nervous system (CNS) pathogenesis is unclear, and viral RNA is rarely detected in cerebrospinal fluid (CSF). To measure viral antigen and inflammatory biomarkers in CSF in relation to neurologic symptoms and disease severity. This cross-sectional study was performed from March 1, 2020, to June 30, 2021, in patients 18 years or older who were admitted to Sahlgrenska University Hospital, Gothenburg, Sweden, with COVID-19. All patients had CSF samples taken because of neurologic symptoms or within a study protocol. Healthy volunteer and prepandemic control groups were included. SARS-CoV-2 infection. Outcomes included CSF SARS-CoV-2 nucleocapsid antigen (N-Ag) using an ultrasensitive antigen capture immunoassay platform and CSF biomarkers of immune activation (neopterin, β2-microglobulin, and cytokines) and neuronal injury (neurofilament light protein [NfL]). Forty-four patients (median [IQR] age, 57 [48-69] years; 30 [68%] male; 26 with moderate COVID-19 and 18 with severe COVID-19 based on the World Health Organization Clinical Progression Scale), 10 healthy controls (median [IQR] age, 58 [54-60] years; 5 [50%] male), and 41 patient controls (COVID negative without evidence of CNS infection) (median [IQR] age, 59 [49-70] years; 19 [46%] male) were included in the study. Twenty-one patients were neuroasymptomatic and 23 were neurosymptomatic (21 with encephalopathy). In 31 of 35 patients for whom data were available (89%), CSF N-Ag was detected; viral RNA test results were negative in all. Nucleocapsid antigen was significantly correlated with CSF neopterin (r = 0.38; P = .03) and interferon γ (r = 0.42; P = .01). No differences in CSF N-Ag concentrations were found between patient groups. Patients had markedly increased CSF neopterin, β2-microglobulin, interleukin (IL) 2, IL-6, IL-10, and tumor necrosis factor α compared with controls. Neurosymptomatic patients had significantly higher median (IQR) CSF interferon γ (86 [47-172] vs 21 [17-81] fg/mL; P = .03) and had a significantly higher inflammatory biomarker profile using principal component analysis compared with neuroasymptomatic patients (0.54; 95% CI, 0.03-1.05; P = .04). Age-adjusted median (IQR) CSF NfL concentrations were higher in patients compared with controls (960 [673-1307] vs 618 [489-786] ng/L; P = .002). No differences were seen in any CSF biomarkers in moderate compared with severe disease. In this study of Swedish adults with COVID-19 infection and neurologic symptoms, compared with control participants, viral antigen was detectable in CSF and correlated with CNS immune activation. Patients with COVID-19 had signs of neuroaxonal injury, and neurosymptomatic patients had a more marked inflammatory profile that could not be attributed to differences in COVID-19 severity. These results highlight the clinical relevance of neurologic symptoms and suggest that viral components can contribute to CNS immune responses without direct viral invasion.

Applying mixture model methods to SARS-CoV-2 serosurvey data from Geneva

Serosurveys are an important tool to estimate the true extent of the current SARS-CoV-2 pandemic. So far, most serosurvey data have been analyzed with cutoff-based methods, which dichotomize individual measurements into sero-positives or negatives based on a predefined cutoff. However, mixture model methods can gain additional information from the same serosurvey data. Such methods refrain from dichotomizing individual values and instead use the full distribution of the serological measurements from pre-pandemic and COVID-19 controls to estimate the cumulative incidence. This study presents an application of mixture model methods to SARS-CoV-2 serosurvey data from the SEROCoV-POP study from April and May 2020 in Geneva (2766 individuals). Besides estimating the total cumulative incidence in these data (8.1% (95% CI: 6.8%–9.9%)), we applied extended mixture model methods to estimate an indirect indicator of disease severity, which is the fraction of cases with a distribution of antibody levels similar to hospitalized COVID-19 patients. This fraction is 51.2% (95% CI: 15.2%–79.5%) across the full serosurvey, but differs between three age classes: 21.4% (95% CI: 0%–59.6%) for individuals between 5 and 40 years old, 60.2% (95% CI: 21.5%–100%) for individuals between 41 and 65 years old and 100% (95% CI: 20.1%–100%) for individuals between 66 and 90 years old. Additionally, we find a mismatch between the inferred negative distribution of the serosurvey and the validation data of pre-pandemic controls. Overall, this study illustrates that mixture model methods can provide additional insights from serosurvey data.

Impact of the COVID-19 Pandemic on Characteristics of Cutaneous Tumors Treated by Mohs Micrographic Surgery

The COVID-19 pandemic has impacted the practice of Mohs micrographic surgery (MMS). We sought to determine the characteristics of skin cancers treated by MMS during the pandemic compared with prepandemic controls. A retrospective chart review was conducted. Tumors included were all treated in accordance with best practice guidelines set forth by state- and national-level professional governing bodies. Bivariate and multivariate analyses were performed to compare outcome variables. Changes in tumor characteristics during the pandemic are of clinical significance, potentially affecting extent of reconstructive surgery, cost, operating time, and future tumor characteristics.

SARS-CoV-2 epitope-specific CD4+ memory T cell responses across COVID-19 disease severity and antibody durability.

CD4+ T cells are central to long-term immunity against viruses through the functions of T helper-1 (Th1) and T follicular helper (Tfh) cell subsets. To better understand the role of these subsets in COVID-19 immunity, we conducted a longitudinal study of SARS-CoV-2-specific CD4+ T cell and antibody responses in convalescent subjects who seroconverted during the first wave of the pandemic in Boston, Massachusetts, United States, across a range of COVID-19 disease severities. Analyses of spike (S) and nucleocapsid (N) epitope-specific CD4+ T cells using peptide and major histocompatibility complex class II (peptide:MHCII) tetramers demonstrated expanded populations of T cells recognizing the different SARS-CoV-2 epitopes in most subjects compared to pre-pandemic controls. Individuals who experienced a milder disease course not requiring hospitalization had a greater percentage of circulating Tfh (cTfh) and Th1 cells among SARS-CoV-2-specific cells. Analysis of SARS-CoV-2-specific CD4+ T cells responses in a subset of individuals with sustained anti-S antibody responses following viral clearance also revealed an increased proportion of memory cTfh cells. Our findings indicate efficient early disease control also predicts favorable long-term adaptive immunity.

The role and diagnostic accuracy of serology for COVID-19

BackgroundThe role and performance of various serological tests for the diagnosis of COVID-19 are unclear. This study aimed to evaluate the performance of seven commercially available serological assays for SARS-CoV-2 antibodies by testing COVID-19 cases and controls.MethodsAdult patients with fever for > 5 days, admitted to a tertiary-care teaching hospital in South India, were enrolled prospectively between June and December 2020. SARS-CoV-2 RT-PCR confirmed patients were classified as cases, and patients with febrile illness with laboratory-confirmed alternative diagnosis and healthy participants were controls. All participants were tested with SCoV-2 Detect™ IgM ELISA kit and SCoV-2 Detect™ IgG ELISA kit (InBios International, Seattle, USA) (Inbios), SARS-CoV-2 Total and SARS-CoV-2 IgG (Siemens Healthcare Diagnostics Inc., Tarrytown, USA) (Siemens), Roche Elecsys® Anti-SARS-CoV-2 (Roche Diagnostics, Rotkreuz, Switzerland) (Roche), Abbott SARS-CoV-2 IgG (Abbott Diagnostics, IL, USA) (Abbott), and Liaison® SARS-CoV-2 S1/S2 IgG (DiaSorinS.p.A., Saluggia, Italy) (Liaison). The sensitivities, specificities, positive predictive values (PPV), negative predictive values (NPV), and accuracies were compared.ResultsThere were 303 participants: 153 cases and 150 controls. ELISA detecting anti-S protein antibody was more sensitive (88.9% for IgG and 86.3% for IgM) than the CLIAs (82.4% for total antibodies and 76.5–85.6% for IgG). Among CLIAs, Roche IgG was most sensitive (85.6%) followed by Abbott (83%) and Liaison (83%). Abbot had the best PPV (88.8%) and was more specific (89.3%) than Liaison (82%) and Roche (82%). Siemens IgG was less sensitive (76.5%) than Siemens Total (82.4%). The specificity of all the serological assays was modest (75–90%). Antibody test positivity increased with the duration of illness reaching 90% after 10 days of illness. When cases were compared against pre-pandemic controls, the IgG gave excellent specificity (98–100%). For seroprevalence studies, InBios IgG had the best accuracy (90.8%) with 88.9% sensitivity and 97.6% specificity.ConclusionThe serological assays are important adjuncts for the diagnosis of COVID-19 in patients with persistent symptoms, especially in the second week of illness. The value of serological diagnostic tests is limited in the first week of illness and they provide additional value in seroprevalence studies. The diagnostic accuracy of the ELISA and CLIA platforms were comparable.

Variances in Humoral Responses to Different Spike Protein Domains After SARS-CoV-2 Vaccination in Lung and Heart Transplant Recipients

PurposeSolid organ transplant recipients are lacking an adequate immune response to SARS-CoV-2 vaccination. Therefore, these patients are still at risk and potentially in need of booster vaccinations. Furthermore, it is important to differentiate between the recipients of distinct organs. The efficacy of SARS-CoV-2 vaccination is usually examined via antibodies specific for the spike protein with assays containing the S1 and receptor-binding-domains (RBD) and rather rarely the S2 domain. To gain information about the humoral response in Tx recipients, it is feasible to compare the immunogenicity of these three domains. To address this, we compared the IgG antibody levels specific for the three spike protein domains in heart (HTx) vs lung (LTx) transplant recipients.MethodsBlood plasma 4-6 weeks after the second dose of SARS-CoV-2 vaccination (85% mRNA) of n=100 LTx and n=40 HTx patients was analysed for S1, S2 and RBD-specific IgG antibodies by Luminex-based multiplex assays. The threshold for positive antibody responses was set separately for each spike domain based on the median MFI + 2σ in an unexposed pre-pandemic control group.ResultsFor all three spike protein domains, HTx patients showed a significantly higher rate of positive IgG responses than the LTx patients (73% vs 43%). The comparison of MFI values for S1-, S2- and RBD-specific IgG further underlines the superior antibody response by HTx patients with higher MFI values for S1 (p = 0.0001, S2 p = 0.008, RBD p < 0.0001). In the LTx cohort, MFI values for S2- (p < 0.0001) as well as for RBD-specific IgG (p < 0.0001) were higher than for S1. The same applies for S2 vs S1 (p < 0.0001) and RBD vs S1 (p = 0.0018) in the HTx cohort. Comparing the MFI of S2 vs RBD, the levels of domain-specific IgG were higher for S2 than RBD in both LTx (p < 0.0001) and HTx patients (p = 0.0914).ConclusionHTx patients exhibit a moderately good IgG response to vaccination while LTx recipients show lower antibody responses. Based on the more efficient antibody production against S2 as opposed to the RBD and especially S1-domain, the S2-specific IgG response should be taken into consideration when evaluating the general immune response and the resulting protection after SARS-CoV-2 vaccination in transplant recipients. Both groups of patients might benefit from booster vaccinations.

Evaluation of SARS-CoV-2 antibody point of care devices in the laboratory and clinical setting.

SARS-CoV-2 antibody tests have been marketed to diagnose previous SARS-CoV-2 infection and as a test of immune status. There is a lack of evidence on the performance and clinical utility of these tests. We aimed to carry out an evaluation of 14 point of care (POC) SARS-CoV-2 antibody tests. Serum from participants with previous RT-PCR (real-time polymerase chain reaction) confirmed SARS-CoV-2 infection and pre-pandemic serum controls were used to determine specificity and sensitivity of each POC device. Changes in sensitivity with increasing time from infection were determined on a cohort of study participants. Corresponding neutralising antibody status was measured to establish whether the detection of antibodies by the POC device correlated with immune status. Paired capillary and serum samples were collected to ascertain whether POC devices performed comparably on capillary samples. Sensitivity and specificity varied between the POC devices and in general did not meet the manufacturers’ reported performance characteristics, which signifies the importance of independent evaluation of these tests. The sensitivity peaked at ≥20 days following onset of symptoms, however sensitivity of 3 of the POC devices evaluated at extended time points showed that sensitivity declined with time. This was particularly marked at >140 days post infection. This is relevant if the tests are to be used for sero-prevalence studies. Neutralising antibody data showed that positive antibody results on POC devices did not necessarily confer high neutralising antibody titres, and that these POC devices cannot be used to determine immune status to the SARS-CoV-2 virus. Comparison of paired serum and capillary results showed that there was a decline in sensitivity using capillary blood. This has implications in the utility of the tests as they are designed to be used on capillary blood by the general population.

The IgA in milk induced by SARS-CoV-2 infection is comprised of mainly secretory antibody that is neutralizing and highly durable over time

Approximately 10% of infants infected with SARS-CoV-2 will experience COVID-19 illness requiring advanced care. A potential mechanism to protect this population is passive immunization via the milk of a previously infected person. We and others have reported on the presence of SARS-CoV-2-specific antibodies in human milk. We now report the prevalence of SARS-CoV-2 IgA in the milk of 74 COVID-19-recovered participants, and find that 89% of samples are positive for Spike-specific IgA. In a subset of these samples, 95% exhibited robust IgA activity as determined by endpoint binding titer, with 50% considered high-titer. These IgA-positive samples were also positive for Spike-specific secretory antibody. Levels of IgA antibodies and secretory antibodies were shown to be strongly positively correlated. The secretory IgA response was dominant among the milk samples tested compared to the IgG response, which was present in 75% of samples and found to be of high-titer in only 13% of cases. Our IgA durability analysis using 28 paired samples, obtained 4-6 weeks and 4-10 months after infection, found that all samples exhibited persistently significant Spike-specific IgA, with 43% of donors exhibiting increasing IgA titers over time. Finally, COVID-19 and pre-pandemic control milk samples were tested for the presence of neutralizing antibodies; 6 of 8 COVID-19 samples exhibited neutralization of Spike-pseudotyped VSV (IC50 range, 2.39-89.4ug/mL) compared to 1 of 8 controls. IgA binding and neutralization capacities were found to be strongly positively correlated. These data are highly relevant to public health, not only in terms of the protective capacity of these antibodies for breastfed infants, but also for the potential use of such antibodies as a COVID-19 therapeutic, given that secretory IgA is highly in all mucosal compartments.

Immunogenicity of a third COVID-19 messenger RNA vaccine dose in primary immunodeficiency disorder patients with functional B-cell defects

Immunogenicity of a third COVID-19 messenger RNA vaccine dose in primary immunodeficiency disorder patients with functional B-cell defects

Abstract TMP17: Demographics, Characteristics, And Outcomes Of Stroke Patients With Concurrent Sars-cov-2 Infection From March 1, 2020 To February 28, 2020: An Analysis From The N3c Database

Background: Studies have shown that patients with ischemic stroke (IS) and concurrent COVID-19 have increased stroke severity. These analyses were limited by use of prepandemic era controls or by utilization of a sample from the early pandemic period when stroke care delivery was affected by lockdown. Studies on the severity of hemorrhagic stroke (HS) in patients with concurrent COVID-19 are few and limited by small sample sizes. Methods: Using the National Institute of Health (NIH) National COVID Cohort Collaborative (N3C) database, we identified patients diagnosed with stroke between Mar 1, 2020 - Feb 28, 2021. Hospitalized stroke patients with concurrent COVID-19 (stroke within 3 months after or one week prior to positive SARS-COV-2 PCR or AG lab test) were matched to all other hospitalized stroke patients in a 1:3 ratio. Nearest neighbor matching with a caliper of 0.25 was used for most clinical and demographic factors; exact matching for race/ethnicity and site. Within our matched sample, we used Poisson regression to calculate stroke severity incident rate ratio (IRR). Results: Our query identified 10,394 patients hospitalized with IS with available NIHSS scores upon admission (802 with concurrent COVID-19 and 9,592 without) and 2138 patients hospitalized with HS (181 with concurrent COVID-19 and 1957 without). Average NIHSS was greater in concurrent groups with both IS and HS (11.1 vs 7.68, p &lt; 0.001 and 15.7 vs 11.7, p &lt; 0.001 respectively). Propensity matched analysis also demonstrated that stroke patients with concurrent COVID-19 had increased initial NIHSS (IS: IRR = 1.4, 95% CI:1.3-1.5, p-value &lt; 0.001; HS: IRR = 1.3, 95% CI:1.2-1.5, p &lt; 0.001). Average NIHSS in both IS and HS patients was greater in the Mar-Apr 2020 epoch than in all other 2 month epochs studied in these respective groups. Conclusions: This analysis suggests that the association between increased stroke severity and concurrent COVID-19 that was observed during the early pandemic was present throughout the pandemic as stroke care utilization normalized. Further work will center on the interaction between COVID-19 illness severity and stroke severity.

Quantitative measurement of IgG to SARS-CoV-2 antigens using monoclonal antibody-based enzyme-linked immunosorbent assays.

ObjectiveStandardised quantitative analysis of the humoral immune response to SARS‐CoV‐2 antigens may be useful for estimating the extent and duration of immunity. The aim was to develop enzyme‐linked immunosorbent assays (ELISAs) for the quantification of human IgG antibodies against SARS‐CoV‐2 antigens.MethodsEnzyme‐linked immunosorbent assays were developed based on monoclonal antibodies against human IgG and recombinant SARS‐CoV‐2 antigens (Spike‐S1 and Nucleocapsid). The WHO 67/086 immunoglobulin and WHO 20/136 SARS‐CoV‐2 references were used for standardisation. Sera of a study group of COVID‐19‐positive subjects (n = 144), pre‐pandemic controls (n = 135) and individuals vaccinated with BioNTech–Pfizer BNT162b2 vaccine (n = 48) were analysed. The study group sera were also tested using EuroImmun SARS‐CoV‐2‐ELISAs and a quantitative S1‐specific fluorescence enzyme immunoassay (FEIA) from Thermo Fisher.ResultsThe ELISA results were repeatable and traceable to international units because of their parallelism to both WHO references. In the study group, median anti‐S1‐IgG concentrations were 102 BAU mL−1, compared to 100 and 1457 BAU mL−1 in the vaccination group after first and second vaccination, respectively. The ELISAs achieved an area under the curve (AUC) of 0.965 (S1) and 0.955 (Nucleocapsid) in receiver operating characteristic (ROC) analysis, and a specificity of 1 (S1) and 0.963 (Nucleocapsid) and sensitivity of 0.903 (S1) and 0.833 (Nucleocapsid) at the maximum Youden index. In comparison, the commercial assays (S1‐FEIA, S1 and Nucleocapsid ELISA EuroImmun) achieved sensitivities of 0.764, 0.875 and 0.882 in the study group, respectively.ConclusionsThe quantitative ELISAs to measure IgG binding to SARS‐CoV‐2 antigens have good analytical and clinical performance characteristics and units traceable to international standards.

Probabilistic classification of anti-SARS-CoV-2 antibody responses improves seroprevalence estimates.

ObjectivesPopulation‐level measures of seropositivity are critical for understanding the epidemiology of an emerging pathogen, yet most antibody tests apply a strict cutoff for seropositivity that is not learnt in a data‐driven manner, leading to uncertainty when classifying low‐titer responses. To improve upon this, we evaluated cutoff‐independent methods for their ability to assign likelihood of SARS‐CoV‐2 seropositivity to individual samples.MethodsUsing robust ELISAs based on SARS‐CoV‐2 spike (S) and the receptor‐binding domain (RBD), we profiled antibody responses in a group of SARS‐CoV‐2 PCR+ individuals (n = 138). Using these data, we trained probabilistic learners to assign likelihood of seropositivity to test samples of unknown serostatus (n = 5100), identifying a support vector machines‐linear discriminant analysis learner (SVM‐LDA) suited for this purpose.ResultsIn the training data from confirmed ancestral SARS‐CoV‐2 infections, 99% of participants had detectable anti‐S and ‐RBD IgG in the circulation, with titers differing > 1000‐fold between persons. In data of otherwise healthy individuals, 7.2% (n = 367) of samples were of uncertain serostatus, with values in the range of 3‐6SD from the mean of pre‐pandemic negative controls (n = 595). In contrast, SVM‐LDA classified 6.4% (n = 328) of test samples as having a high likelihood (> 99% chance) of past infection, 4.5% (n = 230) to have a 50–99% likelihood, and 4.0% (n = 203) to have a 10–49% likelihood. As different probabilistic approaches were more consistent with each other than conventional SD‐based methods, such tools allow for more statistically‐sound seropositivity estimates in large cohorts.ConclusionProbabilistic antibody testing frameworks can improve seropositivity estimates in populations with large titer variability.

Decrease of surgical heart disease treatment during the COVID-19 pandemic (Cardiac Surgery COVID-19 Study - CSC 19 Study).

IntroductionThere are gaps of knowledge regarding the impact of the COVID-19 pandemic on cardiac surgery hospitalization and treatment.AimTo evaluate patient characteristics, patient morbidity, type of procedures, length of hospital stay, early mortality, and outcomes of surgical treatment for the heart diseases during one year after the COVID-19 pandemic compared with the corresponding pre-pandemic year.Material and methodsThis was a retrospective, observational, single-center study of 2881 consecutive patients, who underwent all types of cardiac surgery procedures. The time interval between 1st of March 2019 and 29th of February 2020 was designated as the pre-pandemic control period and between 1st of March 2020 and 28th of February 2021 as the study period.ResultsIn the first year of the COVID-19 pandemic, the number of procedures was reduced by 37%. The greatest decrease was observed during the peak of the pandemic, while during the summer months the number of operations was comparable. During the pandemic, patients waited 22 days longer for surgery, and had a higher surgical risk. There were 135% more urgent procedures performed during the COVID-19 time (433 vs. 184). There was no difference in surgery times, intensive care unit stay period, or hospital stay.ConclusionsWe have confirmed a sharp decline in cardiac surgery during the first year of the COVID-19 pandemic in comparison to the pre-pandemic times. Patients waited longer for surgery, had a higher surgical risk and urgent interventions were performed more frequently during the COVID-19 pandemic.