Vaccination and Omicron BA.1/BA.2 Convalescence Enhance Systemic but Not Mucosal Immunity against BA.4/5.

Rising breakthrough infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.4/5 led to the performance of various studies investigating systemic immunity and neutralizing antibodies in sera, but mucosal immunity remains understudied. In this cohort study, the humoral immune responses, including immunoglobulin levels and the presence of virus-neutralizing antibodies, of 92 vaccinated and/or BA.1/BA.2 convalescent individuals were investigated. Cohorts received two doses of ChAdOx1, BNT162b2, or mRNA-1273 and subsequent booster vaccination with either BNT162b2 or mRNA-1273, following BA.1/BA.2 infection. In addition, vaccinated and nonconvalescent or unvaccinated and BA.1 convalescent individuals were studied. Serum and saliva samples were used to determine SARS-CoV-2 spike-specific IgG and IgA titers and neutralizing activity against replication-competent SARS-CoV-2 wild-type virus and the Omicron BA.4/5 variant. Vaccinated/convalescent cohorts demonstrated strongest neutralization against BA.4/5, with 50% neutralization titer (NT50) values reaching 174.2; however, neutralization was reduced up to 11-fold, compared to wild-type virus. Both BA.1 convalescent and vaccinated nonconvalescent cohorts displayed the weakest neutralization against BA.4/5, with NT50 values being reduced to 4.6, accompanied by lower numbers of positive neutralizers. Additionally, salivary neutralization against wild-type virus was strongest in vaccinated and BA.2 convalescent subjects, but this elevated neutralization efficiency was lost when challenged with BA.4/5. Our data support the contention that current coronavirus disease 2019 (COVID-19) vaccines efficiently induce humoral immunity. However, antiviral effectiveness in serum and saliva is greatly reduced against novel variants of concern. These results suggest an adjustment of current vaccine strategies to an adapted or alternative vaccine delivery, such as mucosal booster vaccinations, which might establish enhanced or even sterilizing immunity against novel SARS-CoV-2 variants. IMPORTANCE Rising incidences of breakthrough infections caused by SARS-CoV-2 Omicron BA.4/5 have been observed. Although various studies were conducted investigating neutralizing antibodies in sera, mucosal immunity was barely evaluated. Here, we investigated mucosal immunity, since the presence of neutralizing antibodies at mucosal entry sites plays a fundamental role in disease limitation. We found strong induction of serum IgG/IgA, salivary IgA, and neutralization against SARS-CoV-2 wild-type virus in vaccinated/convalescent subjects but detected 10-fold reduced (albeit positive) serum neutralization against BA.4/5. Interestingly, vaccinated and BA.2 convalescent patients demonstrated the greatest serum neutralization against BA.4/5, but this advantageous neutralizing effect was not observed in the saliva. Our data support the contention that current COVID-19 vaccines are very efficient against severe/critical disease progression. Moreover, these results suggest an adjustment of the current vaccine strategy to adapted and alternative vaccine delivery, such as mucosal booster vaccinations, to establish robust sterilizing immunity against novel SARS-CoV-2 variants.

Immunization status in patients with multiple sclerosis: A cross-sectional, monocenter study in Austria.

BACKGROUND AND PURPOSE: Patients with multiple sclerosis (MS) under certain disease-modifying therapies (DMT) show a higher risk of infection and a lower immune response to vaccination. Hence, assessing immunization status prior to DMT start and, where necessary, performing vaccinations is  recommended. We aimed to determine the immunization status in MS patients and to identify factors associated with low vaccination rates. METHODS: Patients with MS who were seen at the MS clinic of the Medical University of Innsbruck throughout a period of 14 months in 2020 and 2021 were eligible for inclusion into this prospective, single-center study. Immunization status against 17 different pathogens was obtained from vaccination certificate and by patient questionnaire. Antibody detection against seven antigens was performed in peripheral blood. RESULTS: Of 424 patients with MS at a mean age of 43 ± 12 years, the vast majority had vaccinations against tetanus (94%), diphtheria (92%), and poliomyelitis (90%), whereas a lower proportion had vaccinations against tick-borne encephalitis (70%), pertussis (69%), hepatitis B (65%), rubella (55%), hepatitis A (50%), measles (49%), mumps (47%), and only a minority against influenza (10%), pneumococcal (6%) and meningococcal disease (4%), human papillomavirus (4%), yellow fever (2%), and varicella zoster virus (1%). A total of 87% received vaccination against SARS-CoV-2. Overall, higher vaccination rates were associated with younger age, relapsing disease course, and education level. Misinformation on infectious diseases and vaccines was associated with lower vaccination rates. CONCLUSIONS: The majority of MS patients did not fulfil vaccination recommendations. Efforts to increase vaccination rates, preferentially before DMT start, should be promoted.

Humoral immune response to SARS-CoV-2 third vaccination in patients with multiple sclerosis and healthy controls: A prospective multicenter study.

BACKGROUND: Third vaccination against SARS-CoV-2 is recommended for patients with multiple sclerosis (pwMS), usually six months after the last vaccination. METHODS: In this prospective multicenter study on 292 pwMS and 46 healthy controls (HC), who had all received two vaccinations prior to study enrollment, SARS-CoV-2 IgG response was measured in the month before and 2-4 months after third vaccination. PwMS were categorized as follows: untreated (N-DMT, n = 32), receiving disease-modifying therapy (DMT) with expected humoral response (er-DMT: interferon-beta preparations, glatiramer acetate, dimethyl fumarate, teriflunomide, natalizumab, cladribine, alemtuzumab; n = 120) or no expected humoral response (nr-DMT: S1PMs, CD20mAb; n = 140). RESULTS: PwMS on nr-DMT had significantly lower median antibody levels before (12.1 U/ml [0.4-2500]) and after third vaccination (305 U/ml [0.4-2500]) in comparison to other groups (p<0.001). We did not find differences in antibody levels after homologous (n = 281; 2500 [0.4-2500]) and heterologous (n = 57; 2500 [0.4-2500]) vaccination regime regardless of the DMT group. The DMT group (ß= -0.60; 95% CI -1195.73, -799.10; p<0.001) was associated with antibody levels after third vaccination, while time to revaccination (6 months [1-13]) was not. After third vaccination, seropositivity was reached in 75.8% and 82.2% of pwMS on anti-CD20 mAbs and S1PMs, respectively. Complete B-cell depletion significantly decreased the probability of seroconversion even after the third vaccination (OR 0.14; p = 0.021), whereas time interval to last DMT intake and time to revaccination did not. Twenty-two patients reported a SARS-CoV-2 infection (3 N-DMT, 9 er-DMT, 10 nr-DMT), one being asymptomatic and the rest having a mild course. CONCLUSION: Humoral response to SARS-CoV-2 third vaccination in pwMS is excellent. While reduced by S1PMs and CD20mAb, protective response is still expected in the majority of patients.

12-month SARS-CoV-2 antibody persistency in a Tyrolean COVID-19 cohort.

BACKGROUND: Short-term antibody response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown previously. The further development remains to be determined. METHODS: We prospectively followed 29 coronavirus disease 2019 cases, mean age 44 ± 13.2 years. Except for one participant in whom rheumatoid arthritis existed, all other cases were previously healthy. We determined anti-viral binding antibodies at 2-10 weeks, 3 months, 6 months, and 12 months after disease onset as well as neutralizing antibodies (NAb) against wild type at 6 and 12 months and the B.1.1.7 and B.1.351 variants at month 12. Three binding antibody assays were used, targeting the nucleocapsid protein (NCP), the S1 subunit of the spike protein, and the receptor binding domain (RBD). RESULTS: Antibodies to the RBD persisted for 12 months in all cases with increasing concentrations, whereas antibodies to S1 dropped below cut-off point in 7 participants and NCP antibodies were above cut-off point in only 5 subjects at month 12. The NAb against wild type were detected in all but 2 samples at 12 months of follow-up but clearly less frequently when targeting the variants. In 5 participants who were vaccinated against COVID-19 there was a strong increase of antibodies against S1 and RBD as well as an increase of NAb titres against wild type and the variants. CONCLUSION: There was a persisting antibody response against SARS-CoV­2 up to 12 months after COVID-19 with declining concentrations except for RBD and a strong increase of all antibody concentrations after vaccination.

Comparing humoral immune response to SARS-CoV2 vaccines in people with multiple sclerosis and healthy controls: An Austrian prospective multicenter cohort study.

BACKGROUND AND PURPOSE: SARS-CoV2 vaccination is recommended for patients with multiple sclerosis (pwMS), but response may be limited by disease-modifying-treatments (DMTs). The aim of this study was to compare the rates of humoral immune response and safety of SARS-CoV-2 vaccines in pwMS and healthy controls (HCs). METHODS: In this multicenter prospective study on 456 pwMS and 116 HCs, SARS-CoV-2-IgG response was measured 3 months after the first vaccine dose. The primary endpoint was defined as proportion of patients developing antibodies (seroconversion). Secondary endpoints included antibody level, safety and efficacy. RESULTS: Compared to 97.4% in HCs, seroconversion occurred in 96.7% (88/91) untreated pwMS, 97.1% of patients (135/139) on immunomodulatory DMTs and 61.1% (138/226; p < 0.001) on immunosuppressive DMTs. Seroconversion was lowest in patients on antiCD20 monoclonal antibodies (CD20 mAbs; 52.6%) followed by sphingosine-1-phosphate-receptor-modulators (S1PMs; 63.6%). In the S1PM subgroup, seroconversion increased with lymphocyte count (odds ratio [OR] 1.31 per 0.1 G/L; p = 0.035). In pwMS on CD20 mAbs, B-cell depletion decreased seroconversion (OR 0.52; p = 0.038), whereas time since last DMT did not. Safety of SARS-CoV-2 vaccines in pwMS was excellent. CONCLUSIONS: Humoral response to SARS-CoV2 vaccines in pwMS is generally excellent. While reduced by immunosuppressive DMTs, most importantly by B-cell-depleting CD20 mAbs and S1PMs, seroconversion is still expected in the majority of patients. SARS-CoV2 vaccination should be offered to every MS patient.

Comparative analyses of IgG/IgA neutralizing effects induced by three COVID-19 vaccines against variants of concern.

BACKGROUND: Few studies have directly compared virus-specific antibodies and their neutralizing capacity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wild type (WT) and circulating variants of concern despite the reported high efficacy of messenger RNA (mRNA)- and vector-based vaccines. OBJECTIVE: We assessed SARS-CoV-2 spike protein region 1 (S1)-specific antibodies of BNT162b2, mRNA-1273, and ChAdOx1 vaccinated as well as convalescent coronavirus disease 2019 (COVID-19) patients. We also determined the neutralization ability against SARS-CoV-2 WT and B.1.1.7 (Alpha), B1.1.7 E484K (Alpha-E484K), B.1.351 (Beta), and B.1.617.2 (Delta) variants. METHODS: Serum samples of 107 fully vaccinated or convalescent individuals were analyzed for anti-SARS-CoV-2-S1 IgG and IgA as well as for total anti-SARS-CoV-2 receptor binding domain Ig. Furthermore, neutralization capacity as 50% and 90% neutralization titer values against SARS-CoV-2 WT virus and circulating variants were determined. RESULTS: We observed a robust IgG response in all participants; however, the highest titers were detected in mRNA-based vaccine recipients. In case of serum IgA responses, the difference between mRNA- and vector-based vaccines or convalescent patients was even more pronounced. Interestingly, all 3 vaccines could neutralize all tested variants of concern in addition to WT virus, but in some individuals, only low or no neutralization, especially against Alpha-E484K and the Delta variant, was detected. CONCLUSION: Our study of the efficacy of various COVID-19 vaccines found that mRNA-1273 had the highest neutralization abilities compared to BNT162b2 and ChAdOx1. COVID-19 convalescent patients demonstrated the most heterogeneous range of antibody titers and neutralization abilities, making it hard to assess protection. Furthermore, a significant positive relation between antibodies and the 50% neutralization titer values for immunized and convalescent individuals was determined.

Potent SARS-CoV-2-Specific T Cell Immunity and Low Anaphylatoxin Levels Correlate With Mild Disease Progression in COVID-19 Patients.

T cells play a fundamental role in the early control and clearance of many viral infections of the respiratory system. In SARS-CoV-2-infected individuals, lymphopenia with drastically reduced CD4+ and CD8+ T cells correlates with Coronavirus disease 2019 (COVID-19)-associated disease severity and mortality. In this study, we characterized cellular and humoral immune responses induced in patients with mild, severe and critical COVID-19. Peripheral blood mononuclear cells of 37 patients with mild, severe and critical COVID-19 and 10 healthy individuals were analyzed by IFNγ ELISpot and multi-color flow cytometry upon stimulation with peptide pools covering complete immunodominant SARS-CoV-2 matrix, nucleocapsid and spike proteins. In addition SARS-CoV-2 antibody levels, neutralization abilities and anaphylatoxin levels were evaluated by various commercially available ELISA platforms. Our data clearly demonstrates a significantly stronger induction of SARS-CoV-2 specific CD8+ T lymphocytes and higher IFNγ production in patients with mild compared to patients with severe or critical COVID-19. In all patients SARS-CoV-2-specific antibodies with similar neutralizing activity were detected, but highest titers of total IgGs were observed in critical patients. Finally, elevated anaphylatoxin C3a and C5a levels were identified in severe and critical COVID-19 patients probably caused by aberrant immune complex formation due to elevated antibody titers in these patients. Crucially, we provide a full picture of cellular and humoral immune responses of COVID-19 patients and prove that robust polyfunctional CD8+ T cell responses concomitant with low anaphylatoxin levels correlate with mild infections. In addition, our data indicates that high SARS-CoV-2 antibody titers are associated with severe disease progression.

6-month SARS-CoV-2 antibody persistency in a Tyrolian COVID-19 cohort.

BACKGROUND: As coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus 2 evolved only recently, the persistency of the anti-viral antibody response remains to be determined. METHODS: We prospectively followed 29 coronavirus disease 2019 cases, mean age 44 ± 13.2 years. Except for one participant with a pre-existing diagnosis of rheumatoid arthritis, all other participants were previously healthy. We determined anti-viral binding antibodies at 2-10 weeks, 3 months, and 6 months after disease onset as well as neutralizing antibodies at 6 months. Two binding antibody assays were used, targeting the S1 subunit of the spike protein, and the receptor binding domain. RESULTS: All participants fully recovered spontaneously except for one who had persisting hyposmia. Antibodies to the receptor binding domain persisted for 6 months in all cases with a slight increase of titers, whereas antibodies to S1 dropped below the cut-off point in 2 participants and showed a minimal decrease on average, mainly at month 3 of follow-up in males; however, neutralizing antibodies were detected in all samples at 6 months of follow-up. CONCLUSION: There is a stable and persisting antibody response against acute respiratory syndrome coronavirus 2 at 6 months after infection. Neutralizing antibodies confirm virus specificity. As the number of coronavirus disease 2019 convalescent cases is increasing sharply, antibody testing should be implemented to identify immunized individuals. This information can be helpful in various settings of professional and private life.