SeroNet Pooling Project of immunocompromised populations

Introduction: COVID-19 vaccination substantially reduces morbidity and mortality associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe illness. However, despite effective COVID-19 vaccines many questions remain about the efficacy of vaccines and the durability and robustness of immune responses, especially in immunocompromised persons. The NCI-funded Serological Sciences Network (SeroNet) is a coordinated effort including 11 sites to advance research on the immune response to SARS-CoV-2 infection and COVID-19 vaccination among diverse and vulnerable populations. The goals of the Pooling Project are: (1) to conduct real-world data (RWD) analyses using electronic medical records (EMR) data from four health care systems (Kaiser Permanente Northern California, Northwell Health, Veterans Affairs-Case Western, and Cedars-Sinai) to determine vaccine effectiveness in (a) cancer patients;(b) autoimmune diseases and (c) solid organ transplant recipients (SOTR);(2) to conduct meta-analyses of prospective cohort studies from eight SeroNet institutions (Cedars-Sinai, Johns Hopkins, Northwell Health, Emory University, University of Minnesota, Mount Sinai, Yale University) to determine post-vaccine immune responses in (a) lung cancer patients;(b) hematologic cancers/hematopoietic stem cell transplant (HSCT) recipients;(c) SOTR;(d) lupus. Method(s): For our RWD analyses, data is extracted from EMR using standardized algorithms using ICD-10 codes to identify immunocompromised persons (hematologic and solid organ malignancy;SOTR;autoimmune disease, including inflammatory bowel disease, rheumatoid arthritis, and SLE). We use common case definitions to extract data on demographic, laboratory values, clinical co morbidity, COVID-19 vaccination, SARS-CoV-2 infection and severe COVID-19, and diseasespecific variables. In addition, we pool individual-level data from prospective cohorts enrolling patients with cancer and other immunosuppressed conditions from across network. Surveys and biospecimens from serology and immune profiling are collected at pre-specified timepoints across longitudinal cohorts. Result(s): Currently, we have EMR data extracted from 4 health systems including >715,000 cancer patients, >9,500 SOTR and >180,000 with autoimmune conditions. Prospective cohorts across the network have longitudinal data on >450 patients with lung cancer, >1,200 patients with hematologic malignancies, >400 SOTR and >400 patients with lupus. We will report results examining vaccine effectiveness for prevention of SARS-CoV-2 infection, severe COVID-19 and post-acute sequelae of COVID-19 (PAS-C or long COVID) in cancer patients compared to other immunocompromised conditions. Conclusion(s): Our goal is to inform public health guidelines on COVID-19 vaccine and boosters to reduce SARS-CoV-2 infection and severe illness in immunocompromised populations.

Hospital Protection Correlates in Outpatient Covid-19 Convalescent Plasma Recipients

Background: High titer COVID-19 convalescent plasma (CCP) reduces hospitalizations among immunocompetent outpatients. This study evaluated recipient post-transfusion S receptor binding domain (S-RBD) IgG antibody levels and the association of progressing to hospitalization among unvaccinated outpatients with COVID-19 treated with CCP or control plasma. Method(s): This analysis focused on participants from a multicenter doubleblind, randomized, controlled trial comparing treatment of outpatients with COVID-19 convalescent plasma (CCP) or control plasma without SARS-CoV-2 antibodies. Participants with confirmed SARS-CoV-2 infection were transfused within 9-days of symptom onset between June 2020 and October 2021 (n=110 vaccinated control;n=105 vaccinated CCP;n=464 unvaccinated control;n=472 unvaccinated CCP;total n=574 control and n=577 CCP recipients). All subjects had specimens collected the day prior to transfusion (D-1), within 30 minutes after transfusion (D0), 14 (D14), 28 (D28), and 90 (D90) days post-transfusion. Ancestral SARS-CoV-2 S-RBD was measured by an in-house validated ELISA. All 54 COVID-19-related hospitalizations occurred within 2 weeks of transfusion. Result(s): Post-transfusion anti-S-RBD IgG levels on D0 were significantly greater for CCP (median=4 titer,log3) compared to control (median=2 titer,log3;p< 0.001) recipients. Neither sex nor age impacted antibody levels following CCP treatment at D14, D28, and D90. Vaccinated recipients had greater titers than unvaccinated recipients prior to transfusion with little change in titers post-transfusion. Unvaccinated recipients had low antibody titers on D-1 with CCP recipients exhibiting a significant increase in titer from D-1 to D0 compared to controls (mean fold change=1.89;p< 0.001). Among unvaccinated recipients, those who received CCP transfusion late ( >5 days after symptom onset) and had low D0 antibody levels (< 4.24 titer, log3) had the greatest proportion of hospitalizations (5.5%). In contrast, those who received CCP transfusion early (< 5 days after symptom onset) with high D0 antibody levels ( >4.24 titer, log3) had no hospitalizations. Unvaccinated CCP recipient anti-S-RBD IgG antibody levels on D0 correlated with donor anti-S-RBD IgG antibody levels (r=0.30, p< 0.001). Conclusion(s): Among unvaccinated outpatients with COVID-19, CCP recipient antibody dilutional titers after transfusion over 540 titer correlated with protection against hospitalization when transfusion occurred within 5 days of symptom onset. (Figure Presented).

Pediatric Project ECHO® for Pain: implementation and mixed methods evaluation of a virtual medical education program to support interprofessional pain management in children and youth.

BACKGROUND: Pediatric pain is a complex health challenge requiring a multi-modal management approach. It is critical that healthcare providers (HCPs) have access to ongoing, flexible education and mentorship specific to pediatric pain. However, there are significant gaps in available pain education and a need for more opportunities to support interprofessional training. Project Extension for Community Healthcare Outcomes (Project ECHO®) is a model for delivering online HCP education and cultivating a virtual community of practice. Within the pediatric pain setting, ECHO® has potential to improve local access to specialized pain knowledge, particularly among the physicians, nurses, and allied health providers who primarily manage these cases in community and hospital settings across rural and urban environments. The purpose of this study was three-fold. First, to evaluate the feasibility (participation levels, acceptability) of implementing Project ECHO® in the context of pediatric pain. Second, to measure preliminary program impacts on HCP knowledge, self-efficacy, and clinical practice. Third, to characterize HCP program engagement levels before and after onset of the COVID-19 pandemic. METHODS: A needs assessment was conducted to identify interprofessional education gaps and inform the program curriculum. The no-cost Pediatric ECHO® for Pain program offered TeleECHO sessions (didactic and case-based learning) as well as foundational education. Surveys were distributed at baseline and 6 months to assess outcomes using 7-point Likert scales. Participant engagement was assessed for periods prior to and during the COVID-19 pandemic. Descriptive and inferential statistical analyses were conducted. RESULTS: Eighty-five TeleECHO sessions were hosted, with a mean attendance of 34.1 ± 23.4 HCPs. Acceptability scores at 6 months (n = 33) ranged from 5.0 ± 1.4 to 6.5 ± 0.5. Participants reported statistically significant (p < 0.05) improvements in knowledge (7 out of 7 topics) and self-efficacy (8 out of 9 skills). Most participants reported positive practice impacts, including improved satisfaction with managing children with pain. Exploratory analyses showed a trend of greater engagement from ECHO® learners after onset of the COVID-19 pandemic. CONCLUSIONS: Project ECHO® is a feasible and impactful model for virtual education of interprofessional HCPs in managing pediatric pain.

Higher Proinflammatory Cytokines Are Associated with Increased Antibody Titer After a Third Dose of SARS-CoV-2 Vaccine in Solid Organ Transplant Recipients

Purpose: Solid organ transplant recipients (SOTRs) are at increased risk for severe COVID-19 and exhibit lower antibody responses to SARS-CoV-2 vaccines. This study aimed to determine if pre-vaccination cytokine levels are associated with antibody response to SARS-CoV-2 vaccination. Method(s): A cross-sectional study was performed among 58 SOTRs before and after two-dose mRNA vaccine series, 35 additional SOTRs before and after a third vaccine dose, with comparison to 16 healthy controls (HCs). Anti-spike antibody was assessed using the IgG Euroimmun ELISA. Electrochemiluminescence detectionbased multiplexed sandwich immunoassays were used to quantify plasma cytokine and chemokine concentrations (n=20 analytes). Concentrations between SOTRs and HCs, stratified by ultimate antibody response to the vaccine, were compared using Wilcoxon-rank-sum test with false discovery rates (FDR) computed to correct for multiple comparisons. Result(s): In the study population, 100% of HCs, 59% of SOTRs after two doses and 63% of SOTRs after three doses had a detectable antibody response. Multiple baseline cytokines were elevated in SOTRs versus HCs. There was no significant difference in cytokine levels between SOTRs with high vs low-titer antibodies after two doses of vaccine. However, as compared to poor antibody responders, SOTRs who went on to develop a high-titer antibody response to a third dose of vaccine had significantly higher pre-third dose levels of several innate immune cytokines including IL-17, IL-2Ra, IL-6, IP-10, MIP-1alpha, and TNF-alpha (FDR <0.05). Conclusion(s): A specific inflammatory profile or immune state may identify which SOTRs are likely to develop stronger sero-response and possible protection after a third dose of SARS-CoV-2 vaccine.

Pre-Vaccine Antibodies Against Seasonal Betacoronaviruses Are Associated with Decreased Antibody Response to SARS-CoV-2 mRNA Vaccination in Solid Organ Transplant Recipients

Purpose: The impact of antigenic imprinting, when immune memory of one antigen influences the response to subsequent similar antigens, on the antibody response in solid organ transplant recipients (SOTRs) after SARS-CoV-2 vaccination is currently unknown. This study examines the relationship between seasonal coronaviruses (sCoV) and SARS-CoV-2 antibody levels pre- and post-vaccination in SOTRs. Method(s): Plasma from 52 SOTRs pre- and post-SARS-CoV-2 vaccination (2 doses, mRNA) was analyzed using the Meso Scale Diagnostic Coronavirus Panel 3 (an electrochemiluminescence detection-based multiplexed sandwich immunoassay) for IgG antibodies against alpha sCoVs (229E, NL63), beta sCoVs (HKU1, OC43), and SARS-CoV-2 spike proteins. Changes in IgG titers were determined by paired Wilcoxon rank-sum tests. Spearman correlation analysis was used to determine associations between pre-vaccination anti-sCoVs and post-vaccination anti-SARS-CoV-2 IgG. Result(s): Vaccination increased both anti-SARS-CoV-2 (fold change (FC) 1.9, p<0.001) and anti-beta sCoV (HKU1 [FC 0.05, p<0.001], OC43 [FC 0.8, p<0.001]) IgG titers in SOTRs, but did not increase anti-alpha sCoV IgG. Furthermore, prevaccination anti-beta sCoV (HKU1 [rho= -0.3, p=0.03], OC43 [rho= -0.3, p<0.03]) IgG titers were negatively correlated with post-vaccination anti-SARS-CoV-2 IgG. Conclusion(s): These exploratory findings suggest that prior exposure to seasonal betacoronaviruses may lead to antigenic imprinting in SOTRs that negatively impacts the antibody response to vaccination against the novel pandemic betacoronavirus, SARS-CoV-2.

Effect of a Fourth COVID-19 Vaccine Dose on Omicron Variant Neutralization in Solid Organ Transplant Recipients

Purpose: Humoral response to COVID-19 vaccines is attenuated in many solid organ transplant recipients (SOTRs), necessitating additional primary and booster vaccinations. The omicron variant demonstrates substantial immune evasion, and it is not known if boosters increase neutralizing capacity versus omicron among SOTRs. We therefore investigated SOTR antibody response and neutralization versus variants of concern (VOC) including omicron to a 4th vaccine dose (D4). Method(s): Within a national, prospective observational cohort, 25 SOTRs underwent anti-SARS-CoV-2 spike and receptor binding domain (RBD) IgG testing using the Meso Scale Discovery platform before and 2-4 weeks after D4. Surrogate neutralization (%ACE2 inhibition [%ACE2i], range 0-100% with >20% correlating with live virus neutralization), was measured versus full spike proteins of the ancestral ("vaccine") strain and 5 VOCs including delta and omicron. Change in IgG level and %ACE2i were compared using paired Wilcoxon rank-sum testing. Result(s): Demographics are outlined in Table 1, including median (IQR) age 59 (45- 55) years, 64% kidney recipients, and D4 receipt (60% Moderna, 40% Pfizer) median (IQR) 93 days (28-134) post D3. Two participants had SARS-CoV-2 exposure per anti-nucleocapsid testing, including one incident infection. Overall, anti-RBD (92%- >100%) and anti-spike (84%->92%) seropositivity increased after D4, as did median (IQR) anti-spike IgG 42.3 (4.9-134.2)->228.9 (115.4-655.8) WHO binding antibody units (p<0.05). Median (IQR) %ACE2i significantly increased after D4 vs the vaccine strain 5.8% (0-16.8)->20.6% (5.8-45.9) and delta variant 9.1% (4.9-12.8)->17.1% (10.3-31.7) (both p<0.001). In contrast, no SOTR showed neutralization vs omicron before or after D4: median (IQR) %ACE2i 4.1% (0-6.9)->0.5% (0-5.7) (p=0.11). Conclusion(s): Although a 4th vaccine dose increased anti-spike IgG and neutralizing capacity vs some VOC, there was no omicron variant neutralization among SOTRs. SOTRs may remain at high risk for SARS-CoV-2 infection despite boosting, thus additional protective interventions should be urgently explored. (Figure Presented).

B Cells Fit for Germinal Center Activity Predict Response to a Third Dose of SARS-CoV-2 Vaccine in Solid Organ Transplant Recipients

Purpose: While SARS-CoV-2 vaccination has dramatically reduced COVID-19 severity in the general population, fully vaccinated solid organ transplant recipients (SOTRs) demonstrate reduced seroconversion and increased breakthrough infection rates. Furthermore, a third vaccine dose only increases antibody and T cell responses in a proportion of SOTRs. We sought to investigate the underlying mechanisms resulting in varied humoral responses in SOTRs. Method(s): Within a longitudinal prospective cohort of SOTRs, anti-spike IgG, total and spike-specific B cells were evaluated in 44 SOTR participants before and after a third vaccine dose using high dimensional flow cytometry to assess immunologic and metabolic phenotypes. B cell phenotypes were compared to those of 10 healthy controls who received a standard two-dose mRNA series. Result(s): Notably, even in the absence anti-spike antibody after two doses, spikespecific B cells were detectable in most SOTRs (76%). While 15% of participants were seropositive before the third dose, 72% were seropositive afterward. B cells, however, were differentially skewed towards non-class switched B cells in SOTRs as compared to healthy control B cells. Expansion of spike-specific class-switched B cells in SOTRs following a third vaccine dose correlated with increased classswitched (IgG) antibody titers. Antibody response to a third vaccine dose was associated with expanded populations of germinal center-like (CD10+CD27+) B cells, as well as CD11c+ alternative lineage B cells with specific upregulation of CPT1a, the rate limiting enzyme of fatty acid oxidation and a preferred energy source of germinal center B cells. Conclusion(s): This analysis defines a distinct B cell phenotype in SOTRs who respond to a third SARS-CoV-2 vaccine dose, specifically identifying fatty acid oxidation as pathway that could be targeted to improve vaccine response such as through targeted immunosuppressive modulation. (Figure Presented).

COVID-19 Patient' s Background Frequency on EEG Predictive of Hospital Discharge Disposition

Objective: To determine whether background frequency on encephalogram (EEG) was associated with hospital discharge disposition in COVID-19 patients. Background: Neurological complications, including encephalopathy, have been reported up to 80% of hospitalized COVID-19 patients. It is unclear how encephalopathy during acute illness is related to clinical outcomes in COVID-19 patients. Design/Methods: Subjects were drawn from hospitalized patients who received an EEG at single tertiary center between March 2020 and February 2021. Included were adult subjects with confirmed COVID-19 during hospitalization who were not in the intensive care unit at the time of EEG evaluation. Clinical outcome measured was disposition upon discharge, graded as variables: 0-home, 1-acute rehabilitation, 2-subacute rehabilitation, 3-long term acute care hospital, and 4-death. Background frequency on EEG was used as a measure of encephalopathy severity and was assessed in occipital channels. EEG and medical records were reviewed retrospectively. We used two-independent t test for univariate analysis. Significant variables were then analyzed with multivariate linear regression in SPSS. Study was approved by the University of Chicago IRB. Results: A total of 50 subjects were included. Reasons for EEG were concern for seizure (n=14, 28.0%), altered mental status (n=33, 66.0%), and others (n=3, 6.0%). According to WHO COVID-19 severity scale, on admission 37 (74%) patients had ambulatory disease, 11 (22%) had moderate disease, and 2 (4.0%) severe disease. Thirteen (26.0%) patients received COVID-19 treatment, 4 (8.0%) with steroid. Sodium upon admission, history of epilepsy, cefepime use, intubation, and EEG background frequency were all significant predictors of disposition with univariate analysis (p <0.05). Multivariate analysis showed only intubation (B 1.347, p=0.03) and background frequency on EEG (B -0.282, p <0.001) as independent predictors of disposition. Conclusions: EEG background frequency was a predictor of discharge disposition in COVID-19 patients, and patient with low background frequencies were less likely to be discharged home.

LIMIT of DETECTION of SARS-CoV-2 ANTIBODY ASSAYS

Background: Seroprevalence studies of antibodies to SARS-CoV-2 are important for public health surveillance. Recent studies have shown that antibodies to SARS-CoV-2, both from natural infection and vaccination, decrease with time from exposure. Variation in the performance of antibody assays will impact the estimates of SARS-CoV-2 exposure and vaccination levels in a population. Using standardized serial dilutions, we evaluated 17 SARS-CoV-2 assays to establish an approximate limit of detection for each assay. Methods: The evaluated assays consisted of three chemiluminescent immunoassays (CLIAs), eight standard enzyme-linked immunosorbent assays (ELISAs), and six lateral flow assays (LFAs). All assays either evaluated IgG antibodies or total antibodies to SARS-CoV-2. The target antigen of 14 assays was the spike protein (S) or receptor binding domain (RBD);three assays evaluated antibodies to the nucleocapsid protein (N). A human SARS-CoV-2 serology standard with a WHO SARS-CoV-2 Serology International Standard binding antibody units (BAU) value of 764 BAU/mL to spike IgG and 681 BAU/mL to nucleocapsid IgG was obtained from the Frederick National Laboratory for Cancer Research. Half-logarithmic serial dilutions of the standard were then run in triplicate on each assay. Results: The MSD V-Plex chemiluminescent immunoassays (CLIAs) were the most sensitive by three logs, with positive results at a dilution greater than 1:106 (Figure). Standard ELISAs were less sensitive, with limits of detection ranging from dilutions of 1:20 (Euroimmun NeutraLISA) to 1:1620 (Euroimmun SARS-CoV-2 IgG and Euroimmun QuantiVac). Lateral flow assays (LFAs) were the least sensitive, with only one assay (Wondfo Colloidal Gold) having at least one positive result with a dilution greater than 1:180. Conclusion: As population seroprevalence to SARS-CoV-2 continues to rise, tests with a high limit of detection will be crucial for surveillance studies. As antibody levels decline after vaccination or infection, our data indicate that CLIAs like the MSD assay may provide the best opportunity to capture asymptomatic cases and individuals with low antibody titers.

A portable polyanatomic optico-impedance system for early warning of systemic disease—evaluation in occult hemorrhage

Accurate and reliable non-invasive monitoring of early systemic disease—such as ongoing hemorrhage, sepsis, and acute respiratory disease like COVID-19—is one of the largest unmet needs in biomedicine. An early alert to progression with high sensitivity and an acceptable false-positive rate would allow medical staff to risk-stratify patients, saving resources, lives, and in the context of pandemic disease, minimize staff exposure. Noninvasive technologies have thus far failed to produce a reliable early detection system, reflecting the limitation of uniplex approaches to describe complex pathophysiology. Our team, in collaboration with an STTR start-up, have developed an optico-impedance system combining near-infrared spectroscopy and electrical impedance tomography measured at three locations (thorax, abdomen, limb) together with machine learning methods to provide exceptional diagnostic performance in systemic disease. The optical portion consists of 6 pairs of time-multiplexed red and IR LEDs embedded in custom 3D-printed probes, which are each connected to the leg of a trifurcated fiber bundle, allowing measurement of three-location, two-distance broadband 550-950 nm spectra using a single commercial spectrometer. Data is demultiplexed and analyzed using derivative spectroscopy to quantify oxy/deoxyhemoglobin. Additional diagnostic signal was obtained from: impedance tomography and spectroscopy, ECG and plethysmography. In one of the largest porcine hemorrhage studies to date (n = 60), we demonstrate an 85% accuracy to detect a 2-3% blood volume loss. Preliminary results from 11 healthy human subjects undergoing lower body negative pressure (LBNP) challenge show a 95% accuracy in detecting 15-mmHg changes in pressure—an excellent surrogate for occult hemorrhage. Our system fills a critical need, including in the current pandemic, where clinicians struggle to predict which patients will deteriorate. © 2021 SPIE