Neutralizing antibodies to Omicron after the fourth SARS-CoV-2 mRNA vaccine dose in immunocompromised patients highlight the need of additional boosters

IntroductionImmunocompromised patients have been shown to have an impaired immune response to COVID-19 vaccines.MethodsHere we compared the B-cell, T-cell and neutralizing antibody response to WT and Omicron BA.2 SARS-CoV-2 virus after the fourth dose of mRNA COVID-19 vaccines in patients with hematological malignancies (HM, n=71), solid tumors (ST, n=39) and immune-rheumatological (IR, n=25) diseases. The humoral and T-cell responses to SARS-CoV-2 vaccination were analyzed by quantifying the anti-RBD antibodies, their neutralization activity and the IFN-γ released after spike specific stimulation.ResultsWe show that the T-cell response is similarly boosted by the fourth dose across the different subgroups, while the antibody response is improved only in patients not receiving B-cell targeted therapies, independent on the pathology. However, 9% of patients with anti-RBD antibodies did not have neutralizing antibodies to either virus variants, while an additional 5.7% did not have neutralizing antibodies to Omicron BA.2, making these patients particularly vulnerable to SARS-CoV-2 infection. The increment of neutralizing antibodies was very similar towards Omicron BA.2 and WT virus after the third or fourth dose of vaccine, suggesting that there is no preferential skewing towards either virus variant with the booster dose. The only limited step is the amount of antibodies that are elicited after vaccination, thus increasing the probability of developing neutralizing antibodies to both variants of virus.DiscussionThese data support the recommendation of additional booster doses in frail patients to enhance the development of a B-cell response directed against Omicron and/or to enhance the T-cell response in patients treated with anti-CD20

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

Objective: To evaluate the immune-specific response after the full SARS-CoV-2 vaccination of multiple sclerosis (MS) patients treated with different Disease Modifying drugs by the detection of both serological- and T-cell responses. Methods: Health care workers (HCWs) and MS patients, having completed the two-dose schedule of an mRNA-based vaccine against SARS-CoV-2 in the last 2-4 weeks, were enrolled from two parallel prospective studies conducted in Rome, Italy, at the National Institute for Infectious diseases Spallanzani-IRCSS and San Camillo Forlanini Hospital. Serological 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 FACS analysis. Results: We prospectively enrolled 186 vaccinated individuals: 78 HCWs and 108 MS patients. Twenty-eight MS patients were treated with IFN-β, 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-β. 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-β-treated patients. Importantly, serum neutralizing activity was present in all the HCWs tested and only in a minority of the fingolimod-treated patients (16.6%). T-cell-specific response was detected in the majority of MS patients (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 (rho=0.554, p<0.0001 and rho=0.255, p=0.0078 respectively). Finally, IFN-γ T-cell response was mediated by both CD4+ and CD8+ T cells. Conclusion: mRNA vaccines induce both humoral and cell-mediated specific immune responses against spike peptides in all HCWs and in the majority of MS patients. These results carry relevant implications for managing vaccinations suggesting to promote vaccination in all treated MS patients. Classification of evidence: This study provides Class III data that COVID mRNA vaccination induces both humoral and cell-mediated specific immune responses against viral spike proteins in a majority of MS patients