Incidence and Predictors of Clinical Progression in an Early Treated Covid-19 Cohort

Background: Early treatment for preventing severe outcome of COVID-19 in high-risk not-hospitalized patients (pts) by monoclonal antibodies or antivirals represented a high-priority approach. Real-world evidence (RWE) from observational studies could give information on clinical effectiveness and predictors of treatment failure. Method(s): Single-center observational study on SARS-CoV-2 pts, not requiring hospital admission but having high-risk of severe outcome from COVID-19. All were selected for early treatment with monoclonal antibodies or antivirals from March 2021 to November 2022. Participants were classified according to whether they were hospitalized due to severe COVID-19 or died by day 30 from starting treatment in the outpatient setting (baseline). We conducted a logistic regression analysis with this binary endpoint and 4 main exposures of interest measured at baseline: i) age ( >75 years old) ii) vaccination status iii) VoC, and iv) immunosuppression or having received immunosuppressive therapy. We built a separate model for each of these exposures, which included a specific set of potential confounders. Result(s): 3,491 pts, female 48.6%, median age 67 yrs (IQR 55-77), fully vaccinated 83.7%;previous infection 4.6%;CVD 52.2%;cancer 24.6%;immunodeficiency 40.6%. Prevalence of SARS-CoV-2 VoC: delta 8.7%, BA.1 16.9%, BA.2 6.8%, BA.4/5 12.2, BQ 0.1%, other 3.0% (Tab.1A). Treatment exposure was BAM/ETE 569 (16.5%), CAS/IMD 262 (7.6%), SOT 935 (27.1%), TIX/CIL 79 (2.3%), NMV/r 555 (16.1%), MLP 684 (19.8%), RDV 356 (10.3%). Primary endpoint occurred in 80/3,491 pts with a day-30 incident risk of 2.3% (95%CI 1.8-2.9). Tab.1B shows the unadjusted and adjusted odds ratios (OR) of hospitalization due to COVID-19 or death by day 30. After controlling for potential confounders, higher risk was observed for the unvaccinated (OR 1.95;95%CI 1.03-3.71) and for those affected by immunodeficiency [1.73;1.04-2.89). Having delta as reference variant, an increased risk was observed for BA.2 [2.08;1.00-2.34]. No evidence for a difference was seen by age or other comorbidities. Conclusion(s): In this RWE study, largely represented by vaccinated people and prevalently observed in the Omicron era, the estimated risk of clinical failure of early treatment was slightly higher than that recorded in the experimental arms of randomized studies. The analysis confirms that among those eligible for early treatment, the unvaccinated and those with severe immunodeficiency are at higher risk of developing severe COVID-19. Table 1 -A. Main characteristics of 3,491 not-hospitalized people with mildto-moderate COVID-19 at high risk of severe disease observed between March 2021 to November 2022 according to reaching (n=80) or not reaching (3,411) primary clinical endpoint. B. Odds ratios (OR) of having a COVID-19-related hospitalization or death by different exposure factors.

High prevalence of asymptomatic SARS-CoV-2 infection in a cohort of liver transplant recipients in central Italy

Asymptomatic subjects account for 25 to 45% of SARS-CoV-2 infections, and in particular, subjects on mild immunosuppressive therapy may have symptoms masked and could spread virus for an extended period of time. To determine the cumulative incidence of symptomatic and asymptomatic SARS-CoV-2 infections and associated risk factors, we conducted a prospective clinical and serological survey in a cohort of 278 liver transplant recipients (LTRs) from Central Italy. Three different serology tests were performed every 4 months in 259 LTRs between April 2020 and April 2021: one based on raw extract of whole SARS-CoV-2 virus and two on specific viral antigens (nucleoprotein and receptor binding domain) to detect specific IgG, IgM and IgA. Hundred fifteen LTRs who reported symptoms or close contact with a SARS-CoV-2-positive subject, or had a positive serological result underwent molecular testing by standard screening procedures (RT-PCR on naso-pharyngeal swab). Thirty-one past or active SARS-CoV-2 infections were identified: 14 had positive molecular test (64% symptomatic), and 17 had positive serology only (18% symptomatic). SARS-CoV-2 infection was not statistically related to gender, age, obesity, diabetes, renal impairment, type of anti-rejection therapy or time from transplant. Asymptomatic SARS-CoV-2 cases (61.3%) were more frequent in males and in those with glomerular filtrate rate >50 ml/min. Overall, the addition of repeated serology to standard diagnostic molecular protocols increased detection of SARS-CoV-2 infection from 5.1% to 10.9%. Anti-SARS-CoV-2 seroprevalence among our LTRs (11.2%) is comparable to the general population of Central Italy, considered a medium-impact area. Only one asymptomatic subject (6%) was found to carry SARS-CoV-2 in respiratory tract at the time of serological diagnosis.Copyright © 2021 The Authors

Temporal evolution of humoral and T-cell specific immune response to COVID-19 mRNA vaccine in multiple sclerosis

Background: Although a full course of vaccine against Sars- Cov-2 is effective in most patients with MS (PwMS), the duration of the protection and the efficacy of a booster dose remain poorly explored, especially across different disease modifying treatments (DMTs). Aim(s): To characterize humoral and T-cell immune response along time and following third dose of COVID-19 vaccination in PwMS. Method(s): From an established cohort evaluated at baseline (T0), PwMS were recruited after 24 weeks (T1) from the first cycle of mRNA vaccine and 4 weeks after third dose (T2). At each timepoint we evaluated the serological response by measuring the anti- Region-Binding-Domain (RBD). Cell-mediated response was analyzed by computing interferon (IFN)-gamma in response to spike peptides. Result(s): The baseline cohort consisted of 134 PwMS [mean age 46.6+/-10.8 years;F:92;mean disease duration 15.1+/-9.4 years;26.9% ocrelizumab (OCR) 30.6% fingolimod (FTY), 16.4% cladribine (CLA), 26.1%IFN-s-1a (IFNB)]. Of them, 109 were reassessed at T1, 78 at T2 and 64 completed all evaluations. In the whole cohort there was a significant reduction (p<0.0001) in anti- RBD rate from T0 [76% positive, median 52.8 BAU/ml Interquartile Range (IQR) 1150.9] to T1 (57.8% positive, median 13.2 BAU/ml IQR 95.98] and a significant 20- and 5-fold increase in median titer at T2 (75% positive, median 272.3 BAU/ml IQR 4212.3) from T1 and T0 respectively (p<0.0001). Median IFN-gamma level at T2 was significantly higher than those evaluated at T1 (p<0.0001) and T0 (p=0.009). These latter results were consistent across all DMTs. At T1 the highest detectable anti-RBD response was found in CLA (100%, median 87.7 BAU/ml IQR 22) and IFNB (93.5%;median 126.3 BAU/ml IQR 149.2) cohort, while PwMS treated with FTY and OCR showed 60% (median 8.25 BAU/ml IQR 34.3) and 21% (median 0.8 BAU/ml IQR 6) rate of anti-RBD response respectively. At T2 100% PwMS showed positive anti-RBD response except those treated with OCR (23.8% positive, median 0.6 BAU/ml IQR 4.1). IFN-gamma-S-specific T-cell response was reduced in FTY cohort at both T1 and T2 (3.3 % positive, median 0.8 pg/ml IQR 3.1 and 0.6 pg/ml IQR 2.4 respectively). Conclusion(s): A third dose of COVID-19 vaccine reinforces both humoral and cell-mediated immune response in PwMS on DMTs. Despite vaccination, PwMS treated with OCR and FTY show lower humoral and T-cell specific immune response respectively, suggesting the need of specific treatment to halt COVID-19 in case of infection.

DURABILITY of SARS-CoV-2 mRNA VACCINE IMMUNE RESPONSE in PLWH with ADVANCED DISEASE

Background: Waning of vaccine protection against SARS-CoV-2 infection is currently a concern and durability of specific immunity after vaccination in PLWH is still unknown. The aim of this analysis was to evaluate persistence of immune response to mRNA vaccines in PLWH with advanced disease. Methods: PLWH with a CD4 count ≤200/mm3 and/or previous AIDS, enrolled in a SARS-CoV-2 vaccination program at INMI hospital in Rome, Italy, were evaluated >90 days after 2nd dose of BNT162b2 or mRNA-1273 (time T1). Anti-RBD by CLIA, neutralizing antibody (nAb) titers by microneutralization assay (MNA90) and IFNγ production were assessed and response defined as having anti-RBD >7.1 BAU/mL, nAbs ≥1:10, IFNγ >12 pg/mL. Participants were stratified by CD4 count (severe immunodeficiency, SID, ≤200/mm3;minor immunodeficiency, MID, 201-500/mm3;no immunodeficiency, NID, >500/mm3). Waning of immune response was evaluated in a subgroup of responders for whom two values post 2nd dose were available. Paired t-test was used to test the overall decline. ANOVA and logistic regression analysis controlling for age, viral load, CD4 nadir and cancer were used for comparisons by CD4 groups. Results: 221 pts were included (SID=47;MID=98;NID=76);81% male;median age 55 yrs (IQR 49-60);median time from HIV diagnosis 7 yrs (3-15);74% previous AIDS diagnosis;median CD4 nadir 44/mm3 (16-122). All pts receiving ART, 87% with HIV-RNA<50 cp/mL. After a median of 145 (133-157) days after 2nd dose, a detectable anti-RBD response was still present in 83% of SID, 96% of MID and 98% of NID (P=0.0009);nAbs in 38% of SID, 78% of MID and 88% of NID (P<0.0001);IFNγ in 67% of SID, 90% of MID and 92% of NID (P=0.0002). Magnitude of residual immune response at T1 was significantly lower in SID (Figure 1a). By logistic regression, risk of nAbs undetectability was higher in SID (aOR 5.03;95% CI 1.22-20.81) and in MID (aOR 3.77;11.4-12.48) vs NID, while no evidence for a difference was found for anti-RBD and IFNγ. A significant decline of immune response was observed for all immune parameters [mean log2 (SD):-2.66 (1.08), p<0.001, for anti-RBD;-1.23 (1.26), p<0.001, for nAbs;and-0.51 (2.3), p=0.05, for IFNγ], regardless of CD4 groups (Figure 1b/c). Conclusion: A high proportion of PLWH with advanced disease showed a lack of immune response after a median of 5 months from SARS-CoV-2 mRNA vaccination, suggesting an urgent need for a booster dose. A current CD4 ≤200/mm3 was associated with higher risk of vanishing of neutralizing activity.

SARS-CoV-2 Serum Neutralization Assay: A Traditional Tool for a Brand-New Virus

SARS-CoV-2 serum neutralization assay represents the gold standard for assessing antibody-mediated protection in naturally infected and vaccinated individuals. In the present study, 662 serum samples collected from February 2020 to January 2021 from acute and convalescent COVID-19 patients were tested to determine neutralizing antibody (NAb) titers using a microneutralization test (MNT) for live SARS-CoV-2. Moreover, anti-SARS-CoV-2 IgG, IgA, and IgM directed against different viral antigens were measured by high-throughput automated platforms. We observed higher levels of NAbs in elderly (>60 years old) individuals and in patients presenting acute respiratory distress syndrome. SARS-CoV-2 NAbs develop as soon as five days from symptom onset and, despite a decline after the second month, persist for over 11 months, showing variable dynamics. Through correlation and receiver operating characteristic (ROC) curve analysis, we set up a testing algorithm, suitable for the laboratory workload, by establishing an optimal cutoff value of anti-SARS-CoV-2 IgG for convalescent plasma donors to exclude from MNT samples foreseen to have low/negative NAb titers and ineligible for plasma donation. Overall, MNT, although cumbersome and not suitable for routine testing of large sample sizes, remains the reference tool for the assessment of antibody-mediated immunity after SARS-CoV-2 infection. Smart testing algorithms may optimize the laboratory workflow to monitor antibody-mediated protection in COVID-19 patients, plasma donors, and vaccinated individuals.