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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).
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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.
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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).
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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.
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Background: Males have increased rates of severe illness and mortality from SARS-CoV2 compared to females. It is unknown whether this is due to differential care seeking, health status, illness presentation, comorbidities, and/ or treatment responses. Understanding factors associated with sex/genderbased differences in COVID-19 outcomes is important for optimal care and therapeutics. Methods: SARS-CoV-2 test positivity and admission rates were assessed between March and October of 2020 in the Johns Hopkins Medicine (JHM) system of five hospitals. Detailed patient-level data were extracted for hospitalized patients from the JH-CROWN, a COVID-19 registry utilizing the Hopkins Precision Medicine Analytics Platform. Descriptive statistics were used to analyze differences between males and females. Results: 57% of 213,175 tests were done in females with a similar positivity rate (8.2% F vs 8.9%M). Males were more frequently hospitalized(28%F vs 33%M). Of 2608 hospitalized, more males reported fever, whereas more females reported headache, loss of smell and vomiting(p<0.05). Females had more favorable presenting respiratory parameters with lower respiratory rates and higher SpO2:FiO2 ratios(p<0.001). There was a similar burden of comorbities (Charlson score) but differences in specific comorbidities: obesity and asthma higher among females(p<0.001), heart disease (p=0.06), complicated hypertension(p<0.01), chronic kidney disease, smoking and alcohol use higher among males(p<0.001). Admission and peak lab values showed lower IL-6, ferritin, CRP, higher absolute lymphocyte count and lower neutrophil:lymphocyte ratio in females(p=0.001 for all), but no difference in D-dimer or ESR. Test of interaction between sex and age was significant for IL-6 and ferritin(F test, p<0.05). Males and females received medications against SARS-CoV-2 with similar frequency with exception of tocilizumab which was used more frequently in males. Males had a higher incidence of severe/death outcomes across all ages (28% vs 36%, p<0.001) and in particular among the 18-49 age group (11% v 25%, p<0.001). Conclusion: Females were less frequently admitted to the hospital after a diagnosis with SARS-CoV-2 infection. Despite an excess of obesity, females had a lower severity of respiratory parameters and lower inflammatory markers on presentation and had a lower frequency of severe outcomes from SARS-CoV-2 infection. Sex and age interactions with severe disease highlight critical risk features unique to males and females.
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Background: Sustained molecular detection of SARS-CoV-2 RNA in the upper respiratory tract (URT) is common and confounds infection control efforts in the community. The mean duration of viral RNA detection is ∼17 days, and ∼14% of people with mild or no symptoms have detectable viral RNA for > 4 weeks. We sought to identify host and immune determinants of prolonged SARS-CoV-2 RNA detection in an intensively-sampled prospective observational cohort of outpatients with mild COVID-19 who had concomitant URT virus and mucosal IgG sampling. Methods: 95 participants ≥ 30 years old with known symptom onset date and at least two positive SARS-CoV-2 qRT-PCR results were enrolled. Participants self-collected mid-nasal, oropharyngeal, and oral crevicular fluid (OCF) samples 4-5 times within 3 weeks. 1-3 months after symptom onset, height and weight were measured and nasopharyngeal, salivary, OCF, and blood samples were collected. SARS-CoV-2 qRT-PCR was performed on samples, and positive samples were tested for propagation in virus culture. A multiplex mucosal IgG immunoassay with multiple SARS-CoV-2 antigens was performed on OCF. Plasma titers of neutralizing antibodies, SARS-CoV-2 spike (S) antibodies, and S-receptor binding domain (RBD) antibodies were obtained by microneutralization assay and indirect ELISA. Time to qRT-PCR clearance wasmeasured from symptom onset until the midpoint between the last positive qRT-PCR test and the next negative test. Associations were estimated using a Cox proportional hazard model. Hazards of viral RNA clearance were compared for different age, sex, race/ethnicity, and body mass index (BMI) groups and whether fever was one of the first three symptoms, adjusting for comorbidities and immunocompromised status. Results: See Table for participant characteristics. Of 56 participants with observed viral RNA clearance, mean time to clearance was 33.5 days. The hazard ratio for obesity vs overweight/normal weight was 0.37 (95% CI 0.18-0.78, p=0.009). Elevated mucosal SARS-CoV-2-specific IgG did not associate with faster viral RNA clearance. The maximum time from symptom onset to virus culture. positive sample was 12 days, which is just after the mean time of first positive mucosal SARS-CoV-2-specific IgG detection. Conclusion: Obesity is associated with prolonged SARS-CoV-2 RNA detection in outpatients. Mucosal SARS-CoV-2 IgG is not associated with faster clearance of viral RNA from the URT, suggesting that viral clearance is mediated by select host immune responses.
ABSTRACT
Background: Death from COVID-19 disproportionately affects men, with up to 80% of deaths in severe COVID-19cases being in men. There are a number of potential differences that might contribute to these sex differences.TMPRSS2 is a serine protease that primes the spike protein of SARS-CoV-2, a critical step in viral entry. TMPRSS2is most highly expressed in the prostate where it is under androgen control, upregulated by testosterone anddownregulated by antiandrogens. ACE2, the receptor used for entry into the host cell, is located on the Xchromosome and may also have levels that are altered by hormones, with estradiol downregulating its expression.Previous research on acute lung injury demonstrated that estradiol seems to have beneficial effects on repair of lunginjury. Therefore, our central hypothesis is that hormones may partially contribute to the gender disparity seen inCOVID-19 patients, with high levels of testosterone being harmful and high levels of estrogen being helpful.Bicalutamide is a nonsteroidal antiandrogen that inhibits the action of androgens and, via feedback on thehypothalamic-pituitary axis, upregulates estradiol. We are conducting a phase II clinical trial to determine ifbicalutamide improves the percentage of COVID+ patients with clinical improvement by 7 days. Methods: We will enroll 40 patients who are hospitalized for COVID-19 with minimal respiratory symptoms(respiratory rate <30 and < 6L oxygen by nasal canula). Patients with more severe symptoms or oxygenrequirements, who have taken hormones within the past month, or have pre-existing liver or cardiac disease will beexcluded. Patients will be randomized 1:1 (20 in each arm) to bicalutamide or standard of care and will be stratifiedby gender. The primary outcome is comparing the percentage of patients with clinical improvement at day 7, compared to historical controls based on the World Health Organization categorical scale of clinical improvement.Key secondary clinical endpoints include all-cause mortality at 28 and 60 days, need for mechanical ventilation orICU care, and safety of bicalutamide in this population. We will also determine the impact of bicalutamide therapy onviral infectivity by studying the reduction in viral load, hormone modulation and engagement of the endocrine axis, and immune response modulation promoting pro-repair immune function in patients with COVID-19. Clinical trialregistration number: NCT04374279.