Longitudinal characterisation of B and T-cell immune responses after the booster dose of COVID-19 mRNA-vaccine in people with multiple sclerosis using different disease-modifying therapies.

BACKGROUND: The decline of humoral response to COVID-19 vaccine led to authorise a booster dose. Here, we characterised the kinetics of B-cell and T-cell immune responses in patients with multiple sclerosis (PwMS) after the booster dose. METHODS: We enrolled 22 PwMS and 40 healthcare workers (HCWs) after 4-6 weeks from the booster dose (T3). Thirty HCWs and 19 PwMS were also recruited 6 months (T2) after the first dose. Antibody response was measured by anti-receptor-binding domain (RBD)-IgG detection, cell-mediated response by an interferon (IFN)-γ release assay (IGRA), Th1 cytokines and T-cell memory profile by flow cytometry. RESULTS: Booster dose increased anti-RBD-IgG titers in fingolimod-treated, cladribine-treated and IFN-ß-treated patients, but not in ocrelizumab-treated patients, although antibody titres were lower than HCWs. A higher number of fingolimod-treated patients seroconverted at T3. Differently, T-cell response evaluated by IGRA remained stable in PwMS independently of therapy. Spike-specific Th1-cytokine response was mainly CD4+ T-cell-mediated, and in PwMS was significantly reduced (p<0.0001) with impaired IL-2 production compared with HCWs at T3. In PwMS, total Th1 and IFN-γ CD4+ T-cell responders to spike protein were increased from T2 to T3.Compared with HCWs, PwMS presented a higher frequency of CD4+ and CD8+ terminally differentiated effector memory cells and of CD4+ effector memory (TEM) cells, independently of the stimulus suggesting the association of this phenotype with MS status. CD4+ and CD8+ TEM cell frequency was further increased at T3 compared with T2. CONCLUSIONS: COVID-19 vaccine booster strengthens humoral and Th1-cell responses and increases TEM cells in PwMS.

Third dose of SARS-CoV2 mRNA vaccination produces robust persistent cellular and humoral immune responses in liver transplant recipients.

Weaker responses have been described after two doses of anti-SARS-CoV2 vaccination in liver transplant recipients (LTRs). At the Italian National Institute for Infectious Diseases, 122 LTRs (84% males, median age 64 years) were tested for humoral and cell-mediated immune response after a third doses of anti-SARS-CoV2 mRNA vaccines. Humoral response was measured by quantifying anti-receptor binding domain and neutralizing antibodies; cell-mediated response was measured by quantifying IFN-γ after stimulation of T cells with SARS-CoV-2-specific peptides. Humoral and cellular responses improved significantly compared to the second vaccine dose; 86.4% of previous non-responders to the first 2 vaccine doses (N = 22) became responders. Mycophenolate mofetil-containing regimens were not associated with lower response rates to a third vaccine; shorter time since transplantation (<6 years) was associated with lower humoral and cellular responses to third vaccine. Protective antibodies against Omicron variant were detected in 60% of patients 12 weeks after third vaccine dose.

Booster dose of SARS-CoV-2 messenger RNA vaccines strengthens the specific immune response of patients with rheumatoid arthritis: A prospective multicenter longitudinal study.

OBJECTIVES: To characterize the kinetics of humoral and T-cell responses in rheumatoid arthritis (RA)-patients followed up to 4-6 weeks (T3) after the SARS-CoV-2 vaccine booster dose. METHODS: Health care workers (HCWs, n = 38) and patients with RA (n = 52) completing the messenger RNA vaccination schedule were enrolled at T3. In each cohort, 25 subjects were sampled after 5 weeks (T1) and 6 months (T2) from the first vaccine dose. The humoral response was assessed by measuring anti-receptor-binding domain (RBD) and neutralizing antibodies, the T-cell response by interferon-γ-release assay (IGRA), T cell cytokine production, and B cell phenotype at T3 by flow cytometry. RESULTS: Patients with RA showed a significant reduction of antibody titers from T1 to T2 and a significant increase at T3. T-cell response by IGRA persisted over time in patients with RA, whereas it increased in HCWs. Most patients with RA scored positive for anti-RBD, neutralizing antibody and T-cell responses, although the magnitude was lower than HCWs. The spike-specific-cytokine response was mainly clusters of differentiation (CD)4+ T cells restricted in both cohorts and significantly lower with reduced interleukin-2 response and CD4-antigen-responding naïve T cells in patients with RA. Unswitched memory B cells were reduced in patients with RA compared with HCWs independently of vaccination. CONCLUSION: COVID-19 vaccine booster strengthens the humoral immunity in patients with RA even with a reduced cytokine response.

Association of COVID-19 case fatality rate with disease burden: an ecological analysis in Italy during the first wave.

OBJECTIVES: In Italy, the case fatality rate (CFR) of coronavirus disease 2019 (COVID-19) during the first wave of the pandemic showed significant geographic heterogeneity. The aim of this study was to explore the possible association between the CFR and measures of disease burden in the Italian regions using an ecological approach. METHODS: Cumulated regional data for the period February 24 to May 11, 2020 were analysed to assess the association of the CFR with the cumulative incidence of COVID-19 and the ratio between the maximum number of COVID-19 patients in intensive care units (ICU) and ICU beds available before the pandemic (ICU load), adjusting for median age of the patients at disease onset, number of nasopharyngeal swabs performed per confirmed case, and prevalence of chronic diseases . RESULTS: During the study period, the COVID-19 CFR in the Italian regions ranged between 5.0% and 18.4%. On multivariable regression analysis, the CFR was found to be significantly associated with the cumulative incidence (relative rate (RR) 1.02 per 100 cases/1 million increase), median patient age (RR 1.07 per 1 year increase), and ICU load (RR 1.72, 2.18, and 2.57, for >40-70% vs ≤40%, 70-140% vs ≤40%, and ≥140 vs ≤40%, respectively). CONCLUSIONS: A high burden of COVID-19 may contribute to increased disease fatality, possibly as a result of the increasing demand for care of critically ill patients beyond health system capability.

Prevention from Sharp Injuries in the Hospital Sector: An Italian National Observatory on the Implementation of the Council Directive 2010/32/EU before and during the COVID-19 Pandemic.

Sharp injuries, determining the risk of bloodborne infections and psychological distress in healthcare workers, may be prevented by a set of strategies, legally enforced in Europe through the Directive 2010/32/EU. To assess its level of implementation in Italy, a national survey was conducted in 2017 and again in 2021, evaluating the progress and possible drawbacks of the COVID-19 pandemic. Altogether, 285 safety managers and 330 nurses from a representative sample of 97 and 117 public hospitals were interviewed using a standardized questionnaire. Knowledge of the Directive requirements decreased significantly, with <60% of participants answering correctly in 2021, and nurses' attendance in specific courses dropped to 25% in 2021 compared to 54% in 2017. Over 75% of hospitals introduced multiple safety-engineered devices (SED), though total replacement occurred in <50% of cases; routine SED availability increased for blood collection (89%) and venous access devices (83%). Incorrect behaviors in handling sharps decreased significantly over time. Nurses' HBV vaccination coverage was high (89% in both surveys); in the last year, 97% were vaccinated against COVID, and 47% against influenza. Average annual injuries per hospital did not increase significantly (32 in 2021 vs. 26 in 2017). In 2017, nurses' perceived safety barriers were working in emergency situations (49%) and lack of resources (40%); in 2021, understaffing (73%), physical fatigue (62%), and handling difficulties while wearing full protective equipment (59%). Safety measures were implemented in Italian hospitals, and although the average injuries per hospital did not show a decrease, these measures could have helped protect healthcare workers during the pandemic, mitigating its potential impact on the increase in situations at risk of injury.

Immunogenicity to COVID-19 mRNA vaccine third dose in people living with HIV.

In order to investigate safety and immunogenicity of SARS-CoV-2 vaccine third dose in people living with HIV (PLWH), we analyze anti-RBD, microneutralization assay and IFN-γ production in 216 PLWH on ART with advanced disease (CD4 count <200 cell/mm3 and/or previous AIDS) receiving the third dose of a mRNA vaccine (BNT162b2 or mRNA-1273) after a median of 142 days from the second dose. Median age is 54 years, median CD4 nadir 45 cell/mm3 (20-122), 93% HIV-RNA < 50 c/mL. In 68% of PLWH at least one side-effect, generally mild, is recorded. Humoral response after the third dose was strong and higher than that achieved with the second dose (>2 log2 difference), especially when a heterologous combination with mRNA-1273 as third shot is used. In contrast, cell-mediated immunity remain stable. Our data support usefulness of third dose in PLWH currently receiving suppressive ART who presented with severe immune dysregulation.

SARS-CoV-2 Omicron Variant Neutralization after Third Dose Vaccination in PLWH.

The aim was to measure neutralizing antibody levels against the SARS-CoV-2 Omicron (BA.1) variant in serum samples obtained from vaccinated PLWH and healthcare workers (HCW) and compare them with those against the Wuhan-D614G (W-D614G) strain, before and after the third dose of a mRNA vaccine. We included 106 PLWH and 28 HCWs, for a total of 134 participants. Before the third dose, the proportion of participants with undetectable nAbsT against BA.1 was 88% in the PLWH low CD4 nadir group, 80% in the high nadir group and 100% in the HCW. Before the third dose, the proportion of participants with detectable nAbsT against BA.1 was 12% in the PLWH low nadir group, 20% in the high nadir group and 0% in HCW, respectively. After 2 weeks from the third dose, 89% of the PLWH in the low nadir group, 100% in the high nadir group and 96% of HCW elicited detectable nAbsT against BA.1. After the third dose, the mean log2 nAbsT against BA.1 in the HCW and PLWH with a high nadir group was lower than that seen against W-D614G (6.1 log2 (±1.8) vs. 7.9 (±1.1) and 6.4 (±1.3) vs. 8.6 (±0.8)), respectively. We found no evidence of a different level of nAbsT neutralization by BA.1 vs. W-D614G between PLWH with a high CD4 nadir and HCW (0.40 (-1.64, 2.43); p = 0.703). Interestingly, in PLWH with a low CD4 nadir, the mean log2 difference between nAbsT against BA.1 and W-D614G was smaller in those with current CD4 counts 201-500 vs. those with CD4 counts < 200 cells/mm3 (-0.80 (-1.52, -0.08); p = 0.029), suggesting that in this target population with a low CD4 nadir, current CD4 count might play a role in diversifying the level of SARS-CoV-2 neutralization.

Retention of Neutralizing Response against SARS-CoV-2 Omicron Variant in Sputnik V-Vaccinated Individuals.

The new Omicron variant of SARS-CoV-2, first identified in November 2021, is rapidly spreading all around the world. Omicron has become the dominant variant of SARS-CoV-2. There are many ongoing studies evaluating the effectiveness of existing vaccines. Studies on the neutralizing activity of vaccinated sera against the Omicron variant are currently being carried out in many laboratories. In this study, we have shown the neutralizing activity of sera against the SARS-CoV-2 Omicron variant compared to the reference Wuhan D614G variant in individuals vaccinated with two doses of Sputnik V up to 6 months after vaccination and in individuals who experienced SARS-CoV-2 infection either before or after vaccination. As a control to our study we also measured neutralizing antibody titers in individuals vaccinated with two doses of BNT162b2. The decrease in NtAb titers to the Omicron variant was 8.1-fold for the group of Sputnik V-vaccinated individuals. When the samples were stratified for the time period after vaccination, a 7.6-fold or 8.8-fold decrease in NtAb titers was noticed after up to 3 and 3-to-6 months after vaccination. We observed a 6.7- and 5-fold decrease in Sputnik V-vaccinated individuals experiencing asymptomatic or symptomatic infection, respectively. These results highlight the observation that the decrease in NtAb to the SARS-CoV-2 Omicron variant compared to the Wuhan variant occurs for different COVID-19 vaccines in use, with some showing no neutralization at all, confirming the necessity of a third booster vaccination.

Humoral and Cellular Immune Response Elicited by mRNA Vaccination Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in People Living With Human Immunodeficiency Virus Receiving Antiretroviral Therapy Based on Current CD4 T-Lymphocyte Count.

BACKGROUND: Data on SARS-CoV-2 vaccine immunogenicity in PLWH are currently limited. Aim of the study was to investigate immunogenicity according to current CD4 T-cell count. METHODS: PLWH on ART attending a SARS-CoV-2 vaccination program, were included in a prospective immunogenicity evaluation after receiving BNT162b2 or mRNA-1273. Participants were stratified by current CD4 T-cell count (poor CD4 recovery, PCDR: <200/mm3; intermediate CD4 recovery, ICDR: 200-500/mm3; high CD4 recovery, HCDR: >500/mm3). RBD-binding IgG, SARS-CoV-2 neutralizing antibodies (nAbs) and IFN-γ release were measured. As control group, HIV-negative healthcare workers (HCWs) were used. FINDINGS: Among 166 PLWH, after 1 month from the booster dose, detectable RBD-binding IgG were elicited in 86.7% of PCDR, 100% of ICDR, 98.7% of HCDR, and a neutralizing titre ≥1:10 elicited in 70.0%, 88.2%, and 93.1%, respectively. Compared to HCDR, all immune response parameters were significantly lower in PCDR. After adjusting for confounders, current CD4 T-cell <200/mm3 significantly predicted a poor magnitude of anti-RDB, nAbs and IFN-γ response. As compared with HCWs, PCDR elicited a consistently reduced immunogenicity for all parameters, ICDR only a reduced RBD-binding antibody response, whereas HCDR elicited a comparable immune response for all parameters. CONCLUSION: Humoral and cell-mediated immune response against SARS-CoV-2 were elicited in most of PLWH, albeit significantly poorer in those with CD4 T-cell <200/mm3 versus those with >500 cell/mm3 and HIV-negative controls. A lower RBD-binding antibody response than HCWs was also observed in PLWH with CD4 T-cell 200-500/mm3, whereas immune response elicited in PLWH with a CD4 T-cell >500/mm3 was comparable to HIV-negative population.

The burden of Clostridioides difficile infection in COVID-19 patients: A systematic review and meta-analysis.

OBJECTIVES: The main aim of this systematic review and meta-analysis was to assess the proportion of confirmed COVID-19 patients with Clostridioides difficile infection (CDI) and to describe risk factors and outcome of these patients. METHODS: MEDLINE and Cochrane Central Register of Controlled Trials databases were searched up to July 15, 2021. We included studies reporting data on CDI occurring in patients with a confirmed diagnosis of COVID-19. We pooled proportion of CDI patients using a random effects model (DerSimonian-Laird method) stabilising the variances using the Freeman-Tukey double arcsine transformation. RESULTS: Thirteen studies were included in the systematic review. All the studies retrospectively collected data between February 2020 and February 2021. The reported CDI incidence rates ranged from 1.4 to 4.4 CDI cases per 10,000 patient-days. Seven studies reported data on the number of COVID-19 patients who developed CDI and the total number of COVID-19 patients in the study period and were included in the meta-analysis, comprising 23,697 COVID-19 patients. The overall pooled proportion of COVID-19 patients who had CDI was 1% [95% confidence interval: 1-2]. Among studies reporting CDI occurrence in patients with and without COVID-19, the majority of them reported reduced or unchanged CDI rates compared to pre-COVID period. CONCLUSIONS: CDI is a relevant issue for COVID-19 patients. Adherence to infection prevention and control measures and to the antimicrobial stewardship principles is crucial even during the COVID-19 pandemic.

Kinetics of the B- and T-Cell Immune Responses After 6 Months From SARS-CoV-2 mRNA Vaccination in Patients With Rheumatoid Arthritis.

Objective: To assess the kinetics of the humoral and cell-mediated responses after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in rheumatoid arthritis (RA) patients treated with different immunosuppressive therapies. Methods: Following vaccine completed schedule, health care workers (HCWs, n = 49) and RA patients (n = 35) were enrolled at 5 weeks (T1) and 6 months (T6) after the first dose of BNT162b2-mRNA vaccination. Serological response was assessed by quantifying anti-receptor-binding domain (RBD)-specific immunoglobulin G (IgG) and SARS-CoV-2 neutralizing antibodies, while cell-mediated response was assessed by a whole-blood test quantifying the interferon (IFN)-γ response to spike peptides. B-cell phenotype and IFN-γ-specific T-cell responses were evaluated by flow cytometry. Results: After 6 months, anti-RBD antibodies were still detectable in 91.4% of RA patients, although we observed a significant reduction of the titer in patients under Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4)-Ig [median: 16.4 binding antibody units (BAU)/ml, interquartile range (IQR): 11.3-44.3, p < 0.0001] or tumor necrosis factor (TNF)-α inhibitors (median: 26.5 BAU/ml, IQR: 14.9-108.8, p = 0.0034) compared to controls (median: 152.7 BAU/ml, IQR: 89.3-260.3). All peripheral memory B-cell (MBC) subpopulations, in particular, the switched IgG+ MBCs (CD19+CD27+IgD-IgM-IgG+), were significantly reduced in RA subjects under CTLA-4-Ig compared to those in HCWs (p = 0.0012). In RA patients, a significantly reduced anti-RBD IgG titer was observed at T6 vs. T1, mainly in those treated with CTLA-4-Ig (p = 0.002), interleukin (IL)-6 inhibitors (p = 0.015), and disease-modifying antirheumatic drugs (DMARDs) ± corticosteroids (CCSs) (p = 0.015). In contrast, a weak nonsignificant reduction of the T-cell response was reported at T6 vs. T1. T-cell response was found in 65.7% of the RA patients at T6, with lower significant magnitude in patients under CTLA-4-Ig compared to HCWs (p < 0.0001). The SARS-CoV-2 IFN-γ-S-specific T-cell response was mainly detected in the CD4+ T-cell compartment. Conclusions: In this study, in RA patients after 6 months from COVID-19 vaccination, we show the kinetics, waning, and impairment of the humoral and, to a less extent, of the T-cell response. Similarly, a reduction of the specific response was also observed in the controls. Therefore, based on these results, a booster dose of the vaccine is crucial to increase the specific immune response regardless of the immunosuppressive therapy.

Persistent Spike-specific T cell immunity despite antibody reduction after 3 months from SARS-CoV-2 BNT162b2-mRNA vaccine.

Vaccine is the main public health measure to reduce SARS-CoV-2 transmission and hospitalization, and a massive scientific effort worldwide resulted in the rapid development of effective vaccines. This work aimed to define the dynamics and persistence of humoral and cell-mediated immune response in Health Care Workers who received a two-dose BNT162b2-mRNA vaccination. Serological response was evaluated by quantifying anti-RBD and neutralizing antibodies while cell-mediated response was performed by a whole blood test quantifying Th1 cytokines (IFN-γ, TNF-α, IL-2) produced in response to Spike peptides. BNT162b2-mRNA vaccine induced both humoral and cell-mediated immune response against Spike in all HCW early after the second dose. After 12 weeks from vaccination, the titer of anti-RBD antibodies as well as their neutralization function decreased while the Spike-specific T-cells persisted at the same level as soon after vaccine boost. Of note, a correlation between cellular and humoral response persevered, suggesting the persistence of a coordinated immune response. The long lasting cell-mediated immune response after 3 months from vaccination highlight its importance in the maintaining of specific immunity able to expand again to fight eventual new antigen encountering.

Humoral- and T-Cell-Specific Immune Responses to SARS-CoV-2 mRNA Vaccination in Patients With MS Using Different Disease-Modifying Therapies.

BACKGROUND AND OBJECTIVES: To evaluate the immune-specific response after full severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination of patients with multiple sclerosis (MS) treated with different disease-modifying drugs by the detection of both serologic and T-cell responses. METHODS: Healthcare workers (HCWs) and patients with MS, having completed the 2-dose schedule of an mRNA-based vaccine against SARS-CoV-2 in the past 2-4 weeks, were enrolled from 2 parallel prospective studies conducted in Rome, Italy, at the National Institute for Infectious diseases Spallanzani-IRCSS and San Camillo Forlanini Hospital. Serologic response was evaluated by quantifying the region-binding domain (RBD) and neutralizing antibodies. Cell-mediated response was analyzed by a whole-blood test quantifying interferon (IFN)-γ response to spike peptides. Cells responding to spike stimulation were identified by fluorescence-activated cell sorting analysis. RESULTS: We prospectively enrolled 186 vaccinated individuals: 78 HCWs and 108 patients with MS. Twenty-eight patients with MS were treated with IFN-ß, 35 with fingolimod, 20 with cladribine, and 25 with ocrelizumab. A lower anti-RBD antibody response rate was found in patients treated with ocrelizumab (40%, p < 0.0001) and fingolimod (85.7%, p = 0.0023) compared to HCWs and patients treated with cladribine or IFN-ß. Anti-RBD antibody median titer was lower in patients treated with ocrelizumab (p < 0.0001), fingolimod (p < 0.0001), and cladribine (p = 0.010) compared to HCWs and IFN-ß-treated patients. Serum neutralizing activity was present in all the HCWs tested and in only a minority of the fingolimod-treated patients (16.6%). T-cell-specific response was detected in the majority of patients with MS (62%), albeit with significantly lower IFN-γ levels compared to HCWs. The lowest frequency of T-cell response was found in fingolimod-treated patients (14.3%). T-cell-specific response correlated with lymphocyte count and anti-RBD antibody titer (ρ = 0.554, p < 0.0001 and ρ = 0.255, p = 0.0078 respectively). IFN-γ T-cell response was mediated by both CD4+ and CD8+ T cells. DISCUSSION: mRNA vaccines induce both humoral and cell-mediated specific immune responses against spike peptides in all HCWs and in the majority of patients with MS. These results carry relevant implications for managing vaccinations, suggesting promoting vaccination in all treated patients with MS. CLASSIFICATION OF EVIDENCE: This study provides Class III data that SARS-CoV-2 mRNA vaccination induces both humoral and cell-mediated specific immune responses against viral spike proteins in a majority of patients with MS.

Virological and Serological Characterisation of SARS-CoV-2 Infections Diagnosed After mRNA BNT162b2 Vaccination Between December 2020 and March 2021.

BACKGROUND: Vaccines for coronavirus disease 2019 (COVID-19) are proving to be very effective in preventing severe illness; however, although rare, post-vaccine infections have been reported. The present study focuses on virological and serological features of 94 infections that occurred in Lazio Region (Central Italy) between 27 December 2020, and 30 March 2021, after one or two doses of mRNA BNT162b2 vaccine. METHODS: We evaluated clinical features, virological (viral load; viral infectiousness; genomic characterisation), and serological (anti-nucleoprotein Ig; anti-Spike RBD IgG; neutralising antibodies, nAb) characteristics of 94 post-vaccine infections at the time of diagnosis. Nasopharyngeal swabs (NPSs) and serum samples were collected in the framework of the surveillance activities on SARS-CoV-2 variants established in Lazio Region (Central Italy) and analysed at the National Institute for Infectious Diseases "L. Spallanzani" in Rome. RESULTS: The majority (92.6%) of the post-vaccine infections showed pauci/asymptomatic or mild clinical course, with symptoms and hospitalisation rate significantly less frequent in patients infected after full vaccination course as compared to patients who received a single dose vaccine. Although differences were not statistically significant, viral loads and isolation rates were lower in NPSs from patients infected after receiving two vaccine doses as compared to patients with one dose. Most cases (84%) had nAb in serum at the time of infection diagnosis, which is a sub-group of vaccinees, were found similarly able to neutralise Alpha and Gamma variants. Asymptomatic individuals showed higher nAb titres as compared to symptomatic cases (median titre: 1:120 vs. 1:40, respectively). Finally, the proportion of post-vaccine infections attributed either to Alpha and Gamma variants was similar to the proportion observed in the contemporary unvaccinated population in the Lazio region, and mutational analysis did not reveal enrichment of a defined set of Spike protein substitutions depending on the vaccination status. CONCLUSION: Our study conducted using real-life data, emphasised the importance of monitoring vaccine breakthrough infections, through the characterisation of virological, immunological, and clinical features associated with these events, in order to tune prevention measures in the next phase of the COVID-19 pandemic.

Differential Dynamics of SARS-CoV-2 Binding and Functional Antibodies upon BNT162b2 Vaccine: A 6-Month Follow-Up.

To investigate the dynamic association among binding and functional antibodies in health-care-workers receiving two doses of BNT162b2 mRNA COVID-19-vaccine, SARS-CoV-2 anti-RBD IgG, anti-Trimeric-S IgG, and neutralizing antibodies (Nabs) were measured in serum samples collected at 2 weeks, 3 months, and 6 months from full vaccination. Despite the high correlation, results for anti-RBD and anti-Trimeric S IgG were numerically different even after recalculation to BAU/mL following WHO standards indications. Moreover, after a peak response at 2 weeks, anti-RBD IgG levels showed a 4.5 and 13 fold decrease at 3 and 6 months, respectively, while the anti-Trimeric S IgG presented a less pronounced decay of 2.8 and 4.7 fold. Further different dynamics were observed for Nabs titers, resulting comparable at 3 and 6 months from vaccination. We also demonstrated that at NAbs titers ≥40, the area under the receiver operating characteristic curve and the optimal cutoff point decreased with time from vaccination for both anti-RBD and anti-Trimeric S IgG. The mutating relation among the anti-RBD IgG, anti-Trimeric S IgG, and neutralizing antibodies are indicative of antibody maturation upon vaccination. The lack of standardized laboratory procedures is one factor interfering with the definition of a correlate of protection from COVID-19.

Coordinated cellular and humoral immune responses after two-dose SARS-CoV2 mRNA vaccination in liver transplant recipients.

Limited data are available on risks and benefits of anti-SARS-CoV2 vaccination in solid organ transplant recipients, and weaker responses have been described. At the Italian National Institute for Infectious Diseases, 61 liver transplant recipients underwent testing to describe the dynamics of humoral and cell-mediated immune response after two doses of anti-SARS-CoV2 mRNA vaccines and compared with 51 healthy controls. Humoral response was measured by quantifying both anti-spike and neutralizing antibodies; cell-mediated response was measured by PBMC proliferation assay with IFN-γ and IL-2 production. Liver transplant recipients showed lower response rates compared with controls in both humoral and cellular arms; shorter time since transplantation and multi-drug immunosuppressive regimen containing mycophenolate mofetil were predictive of reduced response to vaccination. Specific antibody and cytokine production, though reduced, were highly correlated in transplant recipients.

ImmunosuppressiveTherapies Differently Modulate Humoral- and T-Cell-Specific Responses to COVID-19 mRNA Vaccine in Rheumatoid Arthritis Patients.

Objective: To assess in rheumatoid arthritis (RA) patients, treated with different immunosuppressive therapies, the induction of SARS-CoV-2-specific immune response after vaccination in terms of anti-region-binding-domain (RBD)-antibody- and T-cell-specific responses against spike, and the vaccine safety in terms of clinical impact on disease activity. Methods: Health care workers (HCWs) and RA patients, having completed the BNT162b2-mRNA vaccination in the last 2 weeks, were enrolled. Serological response was evaluated by quantifying anti-RBD antibodies, while the cell-mediated response was evaluated by a whole-blood test quantifying the interferon (IFN)-γ-response to spike peptides. FACS analysis was performed to identify the cells responding to spike stimulation. RA disease activity was evaluated by clinical examination through the DAS28crp, and local and/or systemic clinical adverse events were registered. In RA patients, the ongoing therapeutic regimen was modified during the vaccination period according to the American College of Rheumatology indications. Results: We prospectively enrolled 167 HCWs and 35 RA patients. Anti-RBD-antibodies were detected in almost all patients (34/35, 97%), although the titer was significantly reduced in patients under CTLA-4-inhibitors (median: 465 BAU/mL, IQR: 103-1189, p<0.001) or IL-6-inhibitors (median: 492 BAU/mL, IQR: 161-1007, p<0.001) compared to HCWs (median: 2351 BAU/mL, IQR: 1389-3748). T-cell-specific response scored positive in most of RA patients [24/35, (69%)] with significantly lower IFN-γ levels in patients under biological therapy such as IL-6-inhibitors (median: 33.2 pg/mL, IQR: 6.1-73.9, p<0.001), CTLA-4-inhibitors (median: 10.9 pg/mL, IQR: 3.7-36.7, p<0.001), and TNF-α-inhibitors (median: 89.6 pg/mL, IQR: 17.8-224, p=0.002) compared to HCWs (median: 343 pg/mL, IQR: 188-756). A significant correlation between the anti-RBD-antibody titer and spike-IFN-γ-specific T-cell response was found in RA patients (rho=0.432, p=0.009). IFN-γ T-cell response was mediated by CD4+ and CD8+ T cells. Finally, no significant increase in disease activity was found in RA patients following vaccination. Conclusion: This study showed for the first time that antibody-specific and whole-blood spike-specific T-cell responses induced by the COVID-19 mRNA-vaccine were present in the majority of RA patients, who underwent a strategy of temporary suspension of immunosuppressive treatment during vaccine administration. However, the magnitude of specific responses was dependent on the immunosuppressive therapy administered. In RA patients, BNT162b2 vaccine was safe and disease activity remained stable.

Predicting the protective humoral response to a SARS-CoV-2 mRNA vaccine.

OBJECTIVES: Simple and standardized methods to establish correlates to vaccine-elicited SARS-CoV-2 protection are needed. METHODS: An observational study on antibody response to a mRNA vaccine (Comirnaty) was performed on health care workers (V, n=120). Recovered COVID-19 patients (N, n=94) were used for comparison. Antibody response was evaluated by a quantitative anti-receptor binding domain IgG (anti-RBD) commercial assay and by virus microneutralization test (MNT), in order to establish a threshold of anti-RBD binding antibody units (BAU) able to predict a robust (≥1:80) MNT titer. RESULTS: Significant correlation between BAU and MNT titers was found in both V and N, being stronger in V (rs=0.91 and 0.57 respectively, p<0.001); a higher incremental trend starting from MNT titer 1:80 was observed in the V group. The 99% probability of high MNT titer (≥1:80) was reached at 1,814 and 3,564 BAU/mL, and the area under the receiver operating characteristic (ROC) curve was 0.99 (CI: 0.99-1.00) and 0.78 (CI: 0.67-0.86) in V and N, respectively. CONCLUSIONS: A threshold of 2,000 BAU/mL is highly predictive of strong MNT response in vaccinated individuals and may represent a good surrogate marker of protective response. It remains to be established whether the present results can be extended to BAU titers obtained with other assays.

Coordinate Induction of Humoral and Spike Specific T-Cell Response in a Cohort of Italian Health Care Workers Receiving BNT162b2 mRNA Vaccine.

Vaccination is the main public health measure to reduce SARS-CoV-2 transmission and hospitalization, and a massive worldwide scientific effort resulted in the rapid development of effective vaccines. This work aimed to define the dynamics of humoral and cell-mediated immune response in a cohort of health care workers (HCWs) who received a two-dose BNT162b2-mRNA vaccination. The serological response was evaluated by quantifying the anti-RBD and neutralizing antibodies. The cell-mediated response was performed by a whole blood test quantifying Th1 cytokines (IFN-γ, TNF-α, IL-2), produced in response to spike peptides. The BNT162b2-mRNA vaccine induced both humoral and cell-mediated immune responses against spike peptides in virtually all HCWs without previous SARS-CoV-2 infection, with a moderate inverse relation with age in the anti-RBD response. Spike-specific T cells produced several Th1 cytokines (IFN-γ, TNF-α, and IL-2), which correlated with the specific-serological response. Overall, our study describes the ability of the BNT162b2 mRNA vaccine to elicit a coordinated neutralizing humoral and spike-specific T cell response in HCWs. Assessing the dynamics of these parameters by an easy immune monitoring protocol can allow for the evaluation of the persistence of the vaccine response in order to define the optimal vaccination strategy.

Impact of Prior Influenza and Pneumoccocal Vaccines on Humoral and Cellular Response to SARS-CoV-2 BNT162b2 Vaccination.

Vaccination against SARS-CoV-2 is considered the most effective method of prevention to contain the pandemic. While highly effective SARS-CoV-2 vaccines are being applied on a large-scale, whether and to what extent the strength of the vaccine-induced immune response could be further potentiated is still an object of debate. Several reports studied the effect of different vaccines on the susceptibility and mortality of COVID-19, with conflicting results. We aimed to evaluate whether previous influenza and/or pneumococcal vaccination had an impact on the specific immune response to the SARS-CoV-2 BNT162b2 mRNA vaccine. The study population consists of 710 workers from our Institute who completed the BNT162b2 schedule and have been tested at least once after the second dose, from 27 December 2020 up to 15 April 2021. Of these, 152 (21.4%) had received an influenza and 215 (30.3%) a concomitant influenza and pneumococcal vaccination, a median of 102 days before the second dose of BNT162b2. Overall, 100% of workers were tested for anti-Spike receptor-binding domain (anti-S/RBD) antibodies, 224 workers for neutralization titer (Micro-neutralization assay, MNA), and 155 workers for a spike-specific T cell interferon-γ response (IFN-γ). The levels of anti-S/RBD, MNA and IFN-γ were evaluated and compared according to sex, age, involvement in direct care of COVID-19 patients, and previous influenza/pneumococcal vaccination. At the univariate analysis, no statistically significant association was observed with regard to a previous influenza and pneumococcal vaccination. A significant lower anti-S/RBD response was observed according to an older age and male sex, while MNA titers were significantly associated to sex but not to age. At the multivariable analysis, workers receiving a concomitant influenza and pneumococcal vaccination or only influenza showed a 58% (p 0.01) and 42% (p 0.07) increase in MNA titers, respectively, compared to those who did not receive an influenza/pneumococcal vaccination. Female workers showed an 81% MNA and a 44% anti-S/RBD increase compared to male workers (p < 0.001). Compared to workers aged 21 to 49 years, those aged 50 or older were associated with a reduction in the anti-S/RBD (16%; p 0.005), MNA (31%; p 0.019), and IFN.g (32%) immune response. Maintaining the influenza and pneumococcal immunization program for the coming season, in which COVID-19 could still be spreading, remains strongly recommended to protect those who are more vulnerable and to limit the potential burden of these infections on the healthcare system.