Differential decline of SARS-CoV-2-specific antibody levels, innate and adaptive immune cells, and shift of Th1/inflammatory to Th2 serum cytokine levels long after first COVID-19.

BACKGROUND: SARS-CoV-2 has triggered a pandemic and contributes to long-lasting morbidity. Several studies have investigated immediate cellular and humoral immune responses during acute infection. However, little is known about long-term effects of COVID-19 on the immune system. METHODS: We performed a longitudinal investigation of cellular and humoral immune parameters in 106 non-vaccinated subjects ten weeks (10 w) and ten months (10 m) after their first SARS-CoV-2 infection. Peripheral blood immune cells were analyzed by multiparametric flow cytometry, serum cytokines were examined by multiplex technology. Antibodies specific for the Spike protein (S), the receptor-binding domain (RBD) and the nucleocapsid protein (NC) were determined. All parameters measured 10 w and 10 m after infection were compared with those of a matched, noninfected control group (n = 98). RESULTS: Whole blood flow cytometric analyses revealed that 10 m after COVID-19, convalescent patients compared to controls had reduced absolute granulocyte, monocyte, and lymphocyte counts, involving T, B, and NK cells, in particular CD3+CD45RA+CD62L+CD31+ recent thymic emigrant T cells and non-class-switched CD19+IgD+CD27+ memory B cells. Cellular changes were associated with a reversal from Th1- to Th2-dominated serum cytokine patterns. Strong declines of NC- and S-specific antibody levels were associated with younger age (by 10.3 years, p < .01) and fewer CD3-CD56+ NK and CD19+CD27+ B memory cells. Changes of T-cell subsets at 10 m such as normalization of effector and Treg numbers, decline of RTE, and increase of central memory T cell numbers were independent of antibody decline pattern. CONCLUSIONS: COVID-19 causes long-term reduction of innate and adaptive immune cells which is associated with a Th2 serum cytokine profile. This may provide an immunological mechanism for long-term sequelae after COVID-19.

A retrospective multicenter study on clinical and serological parameters in patients with MuSK myasthenia gravis with and without general immunosuppression.

Introduction: Muscle-specific kinase (MuSK)- myasthenia gravis (MG) is caused by pathogenic autoantibodies against MuSK that correlate with disease severity and are predominantly of the IgG4 subclass. The first-line treatment for MuSK-MG is general immunosuppression with corticosteroids, but the effect of treatment on IgG4 and MuSK IgG4 levels has not been studied. Methods: We analyzed the clinical data and sera from 52 MuSK-MG patients (45 female, 7 male, median age 49 (range 17-79) years) from Italy, the Netherlands, Greece and Belgium, and 43 AChR-MG patients (22 female, 21 male, median age 63 (range 2-82) years) from Italy, receiving different types of immunosuppression, and sera from 46 age- and sex-matched non-disease controls (with no diagnosed diseases, 38 female, 8 male, median age 51.5 (range 20-68) years) from the Netherlands. We analyzed the disease severity (assessed by MGFA or QMG score), and measured concentrations of MuSK IgG4, MuSK IgG, total IgG4 and total IgG in the sera by ELISA, RIA and nephelometry. Results: We observed that MuSK-MG patients showed a robust clinical improvement and reduction of MuSK IgG after therapy, and that MuSK IgG4 concentrations, but not total IgG4 concentrations, correlated with clinical severity. MuSK IgG and MuSK IgG4 concentrations were reduced after immunosuppression in 4/5 individuals with before-after data, but data from non-linked patient samples showed no difference. Total serum IgG4 levels were within the normal range, with IgG4 levels above threshold (1.35g/L) in 1/52 MuSK-MG, 2/43 AChR-MG patients and 1/45 non-disease controls. MuSK-MG patients improved within the first four years after disease onset, but no further clinical improvement or reduction of MuSK IgG4 were observed four years later, and only 14/52 (26.92%) patients in total, of which 13 (93.3%) received general immunosuppression, reached clinical remission. Discussion: We conclude that MuSK-MG patients improve clinically with general immunosuppression but may require further treatment to reach remission. Longitudinal testing of individual patients may be clinically more useful than single measurements of MuSK IgG4. No significant differences in the serum IgG4 concentrations and IgG4/IgG ratio between AChR- and MuSK-MG patients were found during follow-up. Further studies with larger patient and control cohorts are necessary to validate the findings.

Flow Cytometry-Based Measurement of Antibodies Specific for Cell Surface-Expressed Folded SARS-CoV-2 Receptor-Binding Domains.

BACKGROUND: COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has now become endemic and is currently one of the important respiratory virus infections regularly affecting mankind. The assessment of immunity against SARS-CoV-2 and its variants is important for guiding active and passive immunization and SARS-CoV-2-specific treatment strategies. METHODS: We here devised a novel flow cytometry-based diagnostic platform for the assessment of immunity against cell-bound virus antigens. This platform is based on a collection of HEK-293T cell lines which, as exemplified in our study, stably express the receptor-binding domains (RBDs) of the SARS-CoV-2 S-proteins of eight major SARS-CoV-2 variants, ranging from Wuhan-Hu-1 to Omicron. RESULTS: RBD-expressing cell lines stably display comparable levels of RBD on the surface of HEK-293T cells, as shown with anti-FLAG-tag antibodies directed against a N-terminally introduced 3x-FLAG sequence while the functionality of RBD was proven by ACE2 binding. We exemplify the usefulness and specificity of the cell-based test by direct binding of IgG and IgA antibodies of SARS-CoV-2-exposed and/or vaccinated individuals in which the assay shows a wide linear performance range both at very low and very high serum antibody concentrations. In another application, i.e., antibody adsorption studies, the test proved to be a powerful tool for measuring the ratios of individual variant-specific antibodies. CONCLUSION: We have established a toolbox for measuring SARS-CoV-2-specific immunity against cell-bound virus antigens, which may be considered as an important addition to the armamentarium of SARS-CoV-2-specific diagnostic tests, allowing flexible and quick adaptation to new variants of concern.

Immunogenicity and safety of COVID-19 booster vaccination: A population-based clinical trial to identify the best vaccination strategy.

BACKGROUND: Various SARS-CoV-2 variants of concerns (VOCs) characterized by higher transmissibility and immune evasion have emerged. Despite reduced vaccine efficacy against VOCs, currently available vaccines provide protection. Population-based evidence on the humoral immune response after booster vaccination is crucial to guide future vaccination strategies and in preparation for imminent COVID-19 waves. METHODS: This multicenter, population-based cohort study included 4697 individuals ≥18 years of age who received a booster vaccination. Antibody levels against SARS-CoV-2 receptor binding domain (RBD) and neutralizing antibodies against wild-type (WT) virus and Omicron variants were assessed at baseline (day of booster vaccination) and after four weeks. Safety was evaluated daily within the first week using a participant-completed electronic diary. Antibody levels were compared across different vaccination strategies, taking into account individual host factors. RESULTS: Our main model including 3838 participants revealed that individuals who received a booster with mRNA-1273 compared to BNT162b2 vaccine had a significantly higher increase (95 %CI) in anti-RBD-antibody levels (37,707 BAU/mL [34,575-40,839] vs. 27,176 BAU/mL [26,265-28,087]), and of neutralization levels against WT (1,681 [1490-1872] vs. 1141 [1004-1278] and Omicron variant (422 [369-474] vs. 329 [284-374]). Neutralizing antibody titres highly correlated with anti-RBD antibodies, with neutralizing capacity 4.4 fold higher against WT compared to Omicron. No differences in safety were found between the two booster vaccines. CONCLUSION: Our study underlines the superiority of a booster vaccination with mRNA-1273, independent of the primary vaccination and therefore provides guidance on the vaccination strategy.

Nasal IL-13 production identifies patients with late-phase allergic responses.

BACKGROUND: There is limited knowledge on how local cytokine secretion patterns after nasal allergen challenge correlate with clinical symptoms especially with regard to the "late allergic response," which occurs in approximately 40% to 50% of patients with allergy. OBJECTIVE: We sought to characterize the immunologic and clinical nasal responses to birch pollen allergen challenge with a special focus on the late allergic response. METHODS: In this randomized, double-blind, placebo-controlled trial, birch pollen-allergic participants were challenged with birch pollen extract (n = 20) or placebo (n = 10) on 3 consecutive days. On days 1 and 3, nasal secretions were collected at selected time points over a 24-hour time course for the measurement of 33 inflammatory mediators. Clinical responses were determined through subjective symptom scores and objective nasal airflow measurements. RESULTS: Provoked participants had significantly greater clinical responses and showed significant increases in tryptase and the soluble IL-33 receptor serum stimulation 2 (sST2) in nasal secretions within minutes compared with the placebo group. Eight of 20 provoked participants displayed high IL-13 levels 2 to 8 hours after allergen provocation. This group also showed significant changes in clinical parameters, with a secondary drop in nasal airflow measured by peak nasal inspiratory flow and increased symptoms of nasal obstruction, which significantly differed from IL-13 nonresponders after 6 hours. CONCLUSIONS: IL-13 response status correlates with clinical responses and type 2 cytokine responses in the late phase after allergen provocation.

SARS-CoV-2 infections in "less visible" hospital staff: The roles and safety of environmental services and allied health professionals.

BACKGROUND: During the early SARS-CoV-2 pandemic, all healthcare workers had specific and essential functions. However, environmental services (e.g., cleaning staff) and allied health professionals (e.g., physiotherapists) are often less recognised inpatient care. The aim of our study was to evaluate SARS-CoV-2-infection rates and describe risk factors relevant to workplace transmission and occupational safety amongst healthcare workers in COVID-19 hospitals before the introduction of SARS-CoV-2-specific vaccines. METHODS: This cross-sectional study (from May 2020 to March 2021, standardised WHO early-investigation protocol) is evaluating workplace or health-related data, COVID-19-patient proximity, personal protective equipment (PPE) use, and adherence to infection prevention and control (IPC) measures, anti-SARS-CoV-2-antibody status, and transmission pathways. RESULTS: Out of n = 221 HCW (n = 189 cleaning/service staff; n = 32 allied health professionals), n = 17 (7.7 %) were seropositive. While even SARS-CoV-2-naïve HCW reported SARS-CoV-2-related symptoms, airway symptoms, loss of smell or taste, and appetite were the most specific for a SARS-CoV-2-infection. Adherence to IPC (98.6 %) and recommended PPE use (98.2 %) were high and not associated with seropositivity. In 70.6 %, transmission occurred in private settings; in 23.5 %, at the workplace (by interaction with SARS-CoV-2-positive colleagues [17.6 %] or patient contact [5.9 %]), or remained unclear (one case). CONCLUSIONS: Infection rates were higher in all assessed 'less visible' healthcare-worker groups compared to the general population. Our data indicates that, while IPC measures and PPE may have contributed to the prevention of patient-to-healthcare-worker transmissions, infections were commonly acquired outside of work and transmitted between healthcare workers within the hospital. This finding emphasises the importance of ongoing education on transmission prevention and regular infection screenings at work.

Breakthrough infections with SARS-CoV-2 omicron efficiently boost antibodies from previous BNT162b2 vaccinations.

Objective: To investigate whether SARS-CoV-2 omicron breakthrough infection in individuals after three doses of wildtype-based BNT162b2 increases antibody levels measured by a commercially available wildtype-based immunoassay. Methods: 16 of 21 individuals in a BNT162b2 vaccination cohort (recruited 129 [129-135] days after dose 3) experienced a breakthrough infection (BTI) between March and September 2022. Antibodies to the receptor binding domain (RBP) of the spike protein (Anti-S) were quantified using the wildtype-based Elecsys SARS-CoV-2 S assay (Roche). Antibody responses of triple vaccinated BTI cases were compared to triple vaccinated individuals without breakthrough infection and to 16 matched individuals after primary omicron infection. Results: In the 16 individuals with primary Omicron infection, the anti-S assay returned only very low results (2.25 [0.61-5.80] U/mL). However, in individuals with BTI, Anti-S levels rose from 7,135 [5,870-17,470] U/mL to 21,705 (7,750-46,137.5) U/mL. At the same time, Anti-S concentrations decreased from 9,120 [7,480-13,480] U/mL to 3,830 (2,390-4,220) U/mL in those 5 of 21 vaccinated only. Conclusions: Our data suggest that breakthrough infection with omicron can efficiently boost wild-type antibodies in individuals vaccinated with wild-type BNT162b2.

High immunoglobulin-M levels to oxidation-specific epitopes are associated with lower risk of acute myocardial infarction.

Immunoglobulin M (IgM) autoantibodies to oxidation-specific epitopes (OSEs) can be present at birth and protect against atherosclerosis in experimental models. This study sought to determine whether high titers of IgM titers to OSE (IgM OSE) are associated with a lower risk of acute myocardial infarction (AMI) in humans. IgM to malondialdehyde (MDA)-LDL, phosphocholine-modified BSA, IgM apolipoprotein B100-immune complexes, and a peptide mimotope of MDA were measured within 24 h of first AMI in 4,559 patients and 4,617 age- and sex-matched controls in the Pakistan Risk of Myocardial Infarction Study. Multivariate-adjusted logistic regression was used to estimate odds ratio (OR) and 95% confidence interval for AMI. All four IgM OSEs were lower in AMI versus controls (P < 0.001 for all). Males, smokers and individuals with hypertension and diabetes had lower levels of all four IgM OSE than unaffected individuals (P < 0.001 for all). Compared to the lowest quintile, the highest quintiles of IgM MDA-LDL, phosphocholine-modified BSA, IgM apolipoprotein B100-immune complexes, and MDA mimotope P1 had a lower OR of AMI: OR (95% confidence interval) of 0.67 (0.58-0.77), 0.64 (0.56-0.73), 0.70 (0.61-0.80) and 0.72 (0.62-0.82) (P < 0.001 for all), respectively. Upon the addition of IgM OSE to conventional risk factors, the C-statistic improved by 0.0062 (0.0028-0.0095) and net reclassification by 15.5% (11.4-19.6). These findings demonstrate that IgM OSE provides clinically meaningful information and supports the hypothesis that higher levels of IgM OSE may be protective against AMI.

Associations between nailfold capillary aberrations and autoantibodies in children and adults with Raynaud's phenomenon.

OBJECTIVE: To characterise associations between individual nailfold capillary aberrations with autoantibodies in a cross-sectional study on children and adults with Raynaud's phenomenon (RP). METHODS: Consecutive children and adults with RP and without previously known connective tissue disease (CTD) systemically underwent nailfold capillaroscopy and laboratory tests for the presence of antinuclear antibodies (ANA). The prevalence of individual nailfold capillary aberrations and ANA was assessed, and the associations between individual nailfold capillary aberrations and ANA were analysed separately in children and adolescents. RESULTS: In total, 113 children (median age 15 years) and 2858 adults (median age 48 years) with RP and without previously known CTD were assessed. At least one nailfold capillary aberration was detected in 72 (64%) of included children and in 2154 (75%) of included adults with RP (children vs adults p<0.05). An ANA titre ≥1:80, ≥1:160 or≥1:320 was observed in 29%, 21% or 16% of included children, and in 37%, 27% or 24% of screened adults, respectively. While the occurrence of individual nailfold capillary aberrations was related to the presence of an ANA titre of ≥1:80 in adults (reduced capillary density, avascular fields, haemorrhages, oedema, ramifications, dilations and giant capillaries: each p<0.001), no comparable association between nailfold capillary aberrations and ANA was observed in children with RP without previously known CTD. CONCLUSION: In contrast to adults, the association between nailfold capillary aberrations and ANA might be less pronounced in children. Further studies are warranted to validate these observations in children with RP.

Prophylactic treatment with oral azithromycin in cancer patients during the COVID-19 pandemic (OnCoVID): a randomized, single-blinded, placebo-controlled phase 2 trial.

BACKGROUND: Patients with cancer are at high risk for severe courses of COVID-19. Based on (pre-)clinical data suggesting a potential protective effect due to the immunomodulating properties of azithromycin, we have initiated a prospective randomized trial. METHODS: This randomized, single-center, single-blinded, placebo-controlled phase 2 trial included adult patients with cancer undergoing systemic treatment. Patients were 1:1 randomized to oral azithromycin (1500 mg once weekly for 8 weeks) or placebo. The primary endpoint was the cumulative number of SARS-CoV-2 infections 12 weeks after treatment initiation. RESULTS: In total, 523 patients were screened, 68 patients were randomized, and 63 patients received at least one dose of the study drug. Due to low acceptance and a lack of SARS-CoV-2 infections in the study cohort, the study was prematurely closed. With no reported grade III-IV possibly treatment-related adverse events, azithromycin was generally well tolerated. Overall survival (OS) rates after 12 months were 83.5% and 70.3% in the azithromycin and placebo group, respectively (p = 0.37). Non-SARS-CoV-2 infections occurred in 4/32 (12.5%) in the azithromycin and 3/31 (9.7%) in the placebo group (p = 1). No emergence of azithromycin-resistant S. aureus strains could be observed. According to treatment group, longitudinal alterations in systemic inflammatory parameters were detected for neutrophil/lymphocyte and leukocyte/lymphocyte ratios. CONCLUSION: Although efficacy could not be assessed due to premature closure and low incidence of SARS-CoV-2 infections, azithromycin was associated with a favorable side effect profile in patients with cancer. As other prophylactic treatments are limited, SARS-CoV-2 vaccination remains a high priority in oncological patients. CLINICALTRIALS: gov registration number and date (dd/mm/yyyy): NCT04369365, 30/04/2020.

The accelerated waning of immunity and reduced effect of booster in patients treated with bDMARD and tsDMARD after SARS-CoV-2 mRNA vaccination.

Objectives: This study aimed to assess the duration of humoral responses after two doses of SARS-CoV-2 mRNA vaccines in patients with inflammatory joint diseases and IBD and booster vaccination compared with healthy controls. It also aimed to analyze factors influencing the quantity and quality of the immune response. Methods: We enrolled 41 patients with rheumatoid arthritis (RA), 35 with seronegative spondyloarthritis (SpA), and 41 suffering from inflammatory bowel disease (IBD), excluding those receiving B-cell-depleting therapies. We assessed total anti-SARS-CoV-2 spike antibodies (Abs) and neutralizing Ab titers 6 months after two and then after three doses of mRNA vaccines compared with healthy controls. We analyzed the influence of therapies on the humoral response. Results: Patients receiving biological or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) showed reduced anti-SARS-CoV-2 S Abs and neutralizing Ab titers compared with HC or patients receiving conventional synthetic (cs)DMARDs 6 months after the first two vaccination doses. Anti-SARS-CoV-2 S titers of patients with b/tsDMARDs declined more rapidly, leading to a significant reduction in the duration of vaccination-induced immunity after two doses of SARS-CoV-2 mRNA vaccines. While 23% of HC and 19% of patients receiving csDMARDs were without detectable neutralizing Abs 6 months after the first two vaccination doses, this number was 62% in patients receiving b/tsDMARDs and 52% in patients receiving a combination of csDMARDs and b/tsDMARDs. Booster vaccination led to increased anti-SARS-CoV-2 S Abs in all HC and patients. However, anti-SARS-CoV-2 S Abs after booster vaccination was diminished in patients receiving b/tsDMARDs, either alone or in combination with csDMARDs compared to HC. Conclusion: Patients receiving b/tsDMARDs have significantly reduced Abs and neutralizing Ab titers 6 months after mRNA vaccination against SARS-CoV-2. This was due to a faster decline in Ab levels, indicating a significantly reduced duration of vaccination-induced immunity compared with HC or patients receiving csDMARDs. In addition, they display a reduced response to a booster vaccination, warranting earlier booster vaccination strategies in patients under b/tsDMARD therapy, according to their specific Ab levels.

Growth Differentiation Factor 15 Is Associated with Platelet Reactivity in Patients with Acute Coronary Syndrome.

Bleeding events in patients with acute coronary syndrome (ACS) are a risk factor for adverse outcomes, including mortality. We investigated the association of growth differentiation factor (GDF)-15, an established predictor of bleeding complications, with on-treatment platelet reactivity in ACS patients undergoing coronary stenting receiving prasugrel or ticagrelor. Platelet aggregation was measured by multiple electrode aggregometry (MEA) in response to adenosine diphosphate (ADP), arachidonic acid (AA), thrombin receptor-activating peptide (TRAP, a protease-activated receptor-1 (PAR-1) agonist), AYPGKF (a PAR-4 agonist) and collagen (COL). GDF-15 levels were measured using a commercially available assay. GDF-15 correlated inversely with MEA ADP (r = -0.202, p = 0.004), MEA AA (r = -0.139, p = 0.048) and MEA TRAP (r = -0.190, p = 0.007). After adjustment, GDF-15 was significantly associated with MEA TRAP (ß = -0.150, p = 0.044), whereas no significant associations were detectable for the other agonists. Patients with low platelet reactivity in response to ADP had significantly higher GDF-15 levels (p = 0.005). In conclusion, GDF-15 is inversely associated with TRAP-inducible platelet aggregation in ACS patients treated with state-of-the-art antiplatelet therapy and significantly elevated in patients with low platelet reactivity in response to ADP.

Accelerated waning of immune responses to a third COVID-19 vaccination in patients with immune-mediated inflammatory diseases.

BACKGROUND: A 3rd COVID-19 vaccination is currently recommended for patients under immunosuppression. However, a fast decline of antibodies against the SARS-CoV-2 receptor-binding domain (RBD) of the spike protein has been observed. Currently it remains unclear whether immunosuppressive therapy affects kinetics of humoral and cellular immune responses. METHODS: 50 patients under immunosuppression and 42 healthy controls (HCs) received a 3rd dose of an mRNA-based vaccine and were monitored over a 12-weeks period. Humoral immune response was assessed 4 and 12 weeks after 3rd dose. Antibodies were quantified using the Elecsys Anti-SARS-CoV-2 Spike immunoassay against the receptor-binding domain (RBD) of the spike protein. SARS-CoV-2-specific T cell responses were quantified by IFN-γ ELISpot assays. Adverse events, including SARS-CoV-2 infections, were monitored over a 12-week period. RESULTS: At week 12, reduced anti-RBD antibody levels were observed in IMID patients as compared to HCs (median antibody level 5345 BAU/ml [1781-10,208] versus 9650 BAU/ml [6633-16,050], p < 0.001). Reduction in relative antibody levels was significantly higher in IMID patients as compared to HCs at week 12 (p < 0.001). Lowest anti-RBD antibody levels were detected in IMID patients who received biological disease-modifying anti-rheumatic drugs (DMARDs) or a combination therapy with conventional synthetic and biological DMARDs. Number of SARS-CoV-2-specific T cells against wildtype and Omicron variants remained stable over 12 weeks in IMID patients. No serious adverse events were reported. CONCLUSION: Due to a fast decline in anti-RBD antibodies in IMID patients an early 4th vaccination should be considered in this vulnerable group of patients.

Comparison of the prevalence of SARS-CoV-2 nucleoprotein antibodies in healthcare workers and an unselected adult and paediatric all-comer patient population: insights from a longitudinal study of healthcare workers and concurrent serial cross-sectional studies of patients at an academic medical centre in Austria.

OBJECTIVES: This study aimed to estimate and compare the prevalence of the virus-specific antibodies against the SARS-CoV-2 nucleoprotein antigen (anti-SARS-CoV-2 N) in healthcare workers and an all-comer paediatric and adult patient population. DESIGN, SETTING AND PARTICIPANTS: A longitudinal study enrolling healthcare professionals and concurrent serial cross-sectional studies of unselected all-comer patients were conducted at an Austrian academic medical centre. Healthcare workers were tested at enrolment and after 1, 2, 3, 6 and 12 months. The cross-sectional studies in patients were conducted at three time periods, which roughly coincided with the times after the first, second and third wave of SARS-CoV-2 in Austria (ie, 24 August-7 September 2020; 8-22 February 2021 and 9-23 November 2021). Anti-SARS-CoV-2 N antibodies were measured using a sandwich electrochemiluminescence assay (Roche). RESULTS: In total, 2735 and 9275 samples were measured in 812 healthcare workers (median age: 40 years, 78% female) and 8451 patients (median age: 55 years, 52% female), respectively. Over the entire study period, anti-SARS-CoV-2 N antibodies were detected in 98 of 812 healthcare workers, resulting in a seroprevalence of 12.1% (95% CI 10.0% to 14.5%), which did not differ significantly (p=0.63) from that of the all-comer patient population at the end of the study period (407/3184; 12.8%, 95% CI 11.7% to 14.0%). The seroprevalence between healthcare workers and patients did not differ significantly at any time and was 1.5-fold to 2-fold higher than the number of confirmed cases in Austria throughout the pandemic. In particular, there was no significant difference in the seroprevalence between paediatric and adult patients at any of the tested time periods. CONCLUSION: Throughout the pandemic, healthcare staff and an adult and paediatric all-comer patient population had similar exposure to SARS-CoV-2. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT04407429.

Arterial stiffness in acute coronary syndrome as a potential triage tool: a prospective observational study.

BACKGROUND: Diagnosis and percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) are time-sensitive. Triage and algorithms identify patients at high-risk. However, additional prediction tools are warranted for prioritized care based on predicted coronary pathologies and PCI complexity. Pulse-wave velocity (PWV) is a non-invasive measurement related to cardiovascular morbidity, and their exact value in ACS evaluation is unclear. METHODS: In patients undergoing coronary angiography (CA) and - if warranted - PCI for ACS evaluation at a tertiary university hospital in Vienna, Austria, brachial-ankle (ba)PWV and carotid-femoral (cf)PWV were prospectively measured from January 2020 to January 2021. RESULTS: PWV was measured in 58 patients (60.3% male; 65 [61-69] years). Risk prediction scores (GRACE, CRUSADE, TIMI), cardiac enzymes, and fraction of patients with a three-vessel disease were significantly higher in the pathological PWV ranges. Adjusted for age and comorbidities, baPWV independently predicted the LAD being relevantly stenotic (crude OR=1.416 [1.143-1.755], P=0.001; adjusted OR=1.340 [1.039-1.727], P=0.024; cut-off 15.5 m/s in CART-analysis), being the culprit lesion (crude OR=1.320 [1.094-1.594], P=0.004; adjusted OR=1.311 [1.037-1.657], P=0.024; cut-off 15.5 m/s), and being totally occluded (crude OR=1.422 [1.113-1.818], P=0.005; adjusted OR=1.677 [1.189-2.366], P=0.003; cut-off 19.6 m/s). Moreover, CA or PCI complexity were associated with higher PWV. CONCLUSIONS: Pathological PWV as a surrogate for arterial stiffness, polyvascular disease and a larger atherosclerotic burden was associated with GRACE, CRUSADE, and TIMI scores, and PCI duration and complexity. BaPWV independently predicted relevant LAD pathologies, and is suggested as a potential novel triage and prioritization tool for suspected NSTE-ACS in emergency departments.

Preanalytical stability of SARS-CoV-2 anti-nucleocapsid antibodies.

OBJECTIVES: Anti-nucleocapsid (NC) antibodies are produced in response to SARS-CoV-2 infection. Therefore, they are well suited for the detection of a previous infection. Especially in the case of seroprevalence studies or during the evaluation of a novel in-vitro diagnostic test, samples have been stored at <-70 °C (short- and long-term) or 2-10 °C (short-term) before analysis. This study aimed to assess the impact of different storage conditions relevant to routine biobanking on anti-NC antibodies. METHODS: The preanalytical impact of short-term storage (84 [58-98] days) on <-70 °C and for 14 days at 2-10 °C was evaluated using samples from 111 donors of the MedUni Vienna Biobank. Long-term effects (443 [409-468] days) were assessed using 208 samples from Biobank Graz and 49 samples from Biobank Vienna. Anti-Nucleocapsid antibodies were measured employing electrochemiluminescence assays (Roche Anti-SARS-CoV-2). RESULTS: After short-term storage, the observed changes did not exceed the extent that could be explained by analytical variability. In contrast, results after long-term storage were approximately 20% higher and seemed to increase with storage duration. This effect was independent of the biobank from which the samples were obtained. Accordingly, the sensitivity increased from 92.6 to 95.3% (p=0.008). However, comparisons with data from Anti-Spike protein assays, where these deviations were not apparent, suggest that this deviation could also be explained by the analytical variability of the qualitative Anti-NC assay. CONCLUSIONS: Results from anti-NC antibodies are stable during short-term storage at <-70 °C and 2-10 °C. After long-term storage, a slight increase in sensitivity could not be ruled out.

Multiparametric Prediction Models for Coronavirus Disease 2019 Vaccine Selection: Results of a Comparative Population-Based Cohort Study.

BACKGROUND: An understanding vaccine-dependent effects on protective and sustained humoral immune response is crucial to planning future vaccination strategies against coronavirus disease 2019 (COVID-19). METHODS: In this multicenter, population-based, cohort study including 4601 individuals after primary vaccination against COVID-19 ≥ 4 months earlier we compared factors associated with residual antibody levels against severe acute respiratory syndrome coronavirus-2 receptor-binding domain (RBD) across different vaccination strategies (BNT162b2, mRNA-1273, or ChAdOx1). RESULTS: Our main model including 3787 individuals (2 × BNT162b2, n = 2271; 2 × mRNA-1273, n = 251; 2 × ChAdOx1, n = 1265), predicted significantly lower levels of anti-RBD antibodies after 6 months in individuals vaccinated with ChAdOx1 (392.7 binding antibody units per milliliter [BAU/mL]) compared with those vaccinated with BNT162b2 (1179.5 BAU/mL) or mRNA-1273 (2098.2 BAU/mL). Vaccine-dependent association of antibody levels was found for age with a significant predicted difference in BAU/ml per year for BNT162b2 (-21.5; 95% confidence interval [CI], -24.7 to -18.3) and no significant association for mRNA-1273 (-4.0; 95% CI, -20.0 to 12.1) or ChAdOx1 (1.7; 95% CI, .2 to 3.1). The predicted decrease over time since full immunization was highest in mRNA-1273 (-23.4; 95% CI, -31.4 to -15.4) compared with BNT162b2 (-5.9; 95% CI, -7 to -4.8). CONCLUSIONS: Our study revealed population-based evidence of vaccine-dependent effects of age and time since full immunization on humoral immune response. Findings underline the importance of individualized vaccine selection, especially in elderly individuals.

Increasing test specificity without impairing sensitivity: lessons learned from SARS-CoV-2 serology.

BACKGROUND: Serological tests are widely used in various medical disciplines for diagnostic and monitoring purposes. Unfortunately, the sensitivity and specificity of test systems are often poor, leaving room for false-positive and false-negative results. However, conventional methods were used to increase specificity and decrease sensitivity and vice versa. Using SARS-CoV-2 serology as an example, we propose here a novel testing strategy: the 'sensitivity improved two-test' or 'SIT²' algorithm. METHODS: SIT² involves confirmatory retesting of samples with results falling in a predefined retesting zone of an initial screening test, with adjusted cut-offs to increase sensitivity. We verified and compared the performance of SIT² to single tests and orthogonal testing (OTA) in an Austrian cohort (1117 negative, 64 post-COVID-positive samples) and validated the algorithm in an independent British cohort (976 negatives and 536 positives). RESULTS: The specificity of SIT² was superior to single tests and non-inferior to OTA. The sensitivity was maintained or even improved using SIT² when compared with single tests or OTA. SIT² allowed correct identification of infected individuals even when a live virus neutralisation assay could not detect antibodies. Compared with single testing or OTA, SIT² significantly reduced total test errors to 0.46% (0.24-0.65) or 1.60% (0.94-2.38) at both 5% or 20% seroprevalence. CONCLUSION: For SARS-CoV-2 serology, SIT² proved to be the best diagnostic choice at both 5% and 20% seroprevalence in all tested scenarios. It is an easy to apply algorithm and can potentially be helpful for the serology of other infectious diseases.

Comparison of five Anti-SARS-CoV-2 antibody assays across three doses of BNT162b2 reveals insufficient standardization of SARS-CoV-2 serology.

OBJECTIVES: To investigate the comparability of WHO standard referenced commercial SARS-CoV-2 antibody tests over three doses of BNT162b2 vaccine and up to 14 months. METHODS: 114 subjects (without previous SARS-CoV-2 infection or immunosuppressive medication) vaccinated with three doses of BNT162b2 were included in this study. Antibody levels were quantified 3 weeks after the first dose, 5-6 weeks and 7 months after the second dose, and 4-5 weeks and 4 months after the third dose using the Roche Elecsys SARS-CoV-2 S, the Abbott SARS-CoV-2 IgG II Quant, the DiaSorin LIAISON SARS-CoV-2 TrimericS IgG, the GenScript cPASS sVNT and the TECO sVNT assays. RESULTS: For each time point analyzed, systematic differences are evident between the results in BAU/mL of the three antibody binding assays. The assay ratios change in a time-dependent manner even beyond administering the third dose (Roche measuring 9 and 3 times higher than Abbott and DiaSorin, respectively). However, changes decrease in magnitude with increasing time intervals from the first dose. IgG-based assays show better agreement across them than with Roche (overall correlations: Abbott x DiaSorin: ρ = 0.94 vs. Abbott x Roche: ρ=0.89, p < 0.0001; DiaSorin x Roche: ρ = 0.87, p < 0.0001), but results are not interchangeable. The sVNTs suggest an underestimation of antibody levels by Roche and slight overestimation by both IgG assays after the first vaccine dose. CONCLUSIONS: Standardization of SARS-CoV-2 antibody binding assays still needs to be improved to allow reliable use of variable assay systems for longitudinal analyses.

Safety and immunogenicity of a third COVID-19 vaccination in patients with immune-mediated inflammatory diseases compared with healthy controls.

OBJECTIVES: A third COVID-19 vaccination is recommended for immunosuppressed patients. However, data on immunogenicity and safety of a third COVID-19 vaccination in patients with immune-mediated inflammatory diseases (IMIDs) are sparse and therefore addressed within this clinical trial. METHODS: 60 immunosuppressed patients and 48 healthy controls (HCs) received a third vaccination with an mRNA vaccine. The primary endpoint was defined as the presence of antibody levels against the receptor-binding domain (RBD)>1500 BAU/mL in patients with IMIDs versus HCs. Further endpoints included differences in neutralising antibodies and cellular immune responses after the third vaccination. Reactogenicity was recorded for 7 days, and safety was evaluated until week 4. RESULTS: Rate of individuals with anti-RBD antibodies>1500 BAU/mL was not significantly different after the third vaccination between patients with IMIDs and HCs (91% vs 100% p=0.101). Anti-RBD and neutralising antibody levels were significantly lower in patients with IMIDs after the third vaccination than in HCs (p=0.002 and p=0.016, respectively). In contrast, fold increase in antibody levels between week 0 and 4 was higher in patients with IMIDs. Treatment with biological (b) disease-modifying anti-rheumatic drugs (DMARD) or combination of bDMARDs and conventional synthetic DMARDs was associated with reduced antibody levels. Enhanced cellular immune response to wild type and Omicron peptide stimulation was observed after the third vaccination. No serious adverse event was attributed to the third vaccination. CONCLUSION: Our clinical trial data support the immunogenicity and safety of a third COVID-19 vaccination in patients with IMIDs. However, effects of DMARD therapy on immunogenicity should be considered. TRIAL REGISTRATION NUMBER: EudraCT No: 2021-002693-10.