Cellular and humoral responses after second and third SARS-CoV-2 vaccinations in patients with autoimmune diseases treated with rituximab: specific T cell immunity remains longer and plays a protective role against SARS-CoV-2 reinfections

Comparative Effectiveness of mRNA-1273 and BNT162b2 COVID-19 Vaccines Among Adults with Underlying Medical Conditions: Systematic Literature Review and Pairwise Meta-Analysis Using GRADE

INTRODUCTION

This systematic literature review and pairwise meta-analysis evaluated the comparative effectiveness of mRNA-1273 versus BNT162b2 in patients with at least one underlying medical condition at high risk for severe COVID-19.

METHODS

MEDLINE, Embase, and Cochrane databases were searched for relevant articles from January 1, 2019 to February 9, 2024. Studies reporting effectiveness data from at least two doses of mRNA-1273 and BNT162b2 vaccination in adults with medical conditions at high risk of developing severe COVID-19 according to the US Centers for Disease Control and Prevention were included. Outcomes of interest were SARS-CoV-2 infection (overall, symptomatic, and severe), hospitalization due to COVID-19, and death due to COVID-19. Risk ratios (RRs) were calculated with random effects models. Subgroup analyses by specific medical conditions, number of vaccinations, age, and SARS-CoV-2 variant were conducted. Heterogeneity between studies was estimated with chi-square testing. The certainty of evidence was assessed using the Grading of Recommendations, Assessments, Development, and Evaluations framework.

RESULTS

Sixty-five observational studies capturing the original/ancestral-containing primary series to Omicron-containing bivalent original-BA4-5 vaccinations were included in the meta-analysis. mRNA-1273 was associated with significantly lower risk of SARS-CoV-2 infection (RR, 0.85 [95% CI, 0.79-0.92]; I2 = 92.5%), symptomatic SARS-CoV-2 infection (RR, 0.75 [95% CI, 0.65-0.86]; I2 = 62.3%), severe SARS-CoV-2 infection (RR, 0.83 [95% CI, 0.78-0.89]; I2 = 38.0%), hospitalization due to COVID-19 (RR, 0.88 [95% CI, 0.82-0.94]; I2 = 38.7%), and death due to COVID-19 (RR, 0.84 [95% CI, 0.76-0.93]; I2 = 1.3%) than BNT162b2. Findings were generally consistent across subgroups. Evidence certainty was low or very low because sufficiently powered randomized controlled trials are impractical in this heterogeneous population.

CONCLUSION

Meta-analysis of 65 observational studies showed that vaccination with mRNA-1273 was associated with a significantly lower risk of SARS-CoV-2 infection and COVID-19-related hospitalization and death than BNT162b2 in patients with medical conditions at high risk of severe COVID-19.

Mucosal adenovirus vaccine boosting elicits IgA and durably prevents XBB.1.16 infection in nonhuman primates

A mucosal route of vaccination could prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication at the site of infection and limit transmission. We compared protection against heterologous XBB.1.16 challenge in nonhuman primates (NHPs) ~5 months following intramuscular boosting with bivalent mRNA encoding WA1 and BA.5 spike proteins or mucosal boosting with a WA1-BA.5 bivalent chimpanzee adenoviral-vectored vaccine delivered by intranasal or aerosol device. NHPs boosted by either mucosal route had minimal virus replication in the nose and lungs, respectively. By contrast, protection by intramuscular mRNA was limited to the lower airways. The mucosally delivered vaccine elicited durable airway IgG and IgA responses and, unlike the intramuscular mRNA vaccine, induced spike-specific B cells in the lungs. IgG, IgA and T cell responses correlated with protection in the lungs, whereas mucosal IgA alone correlated with upper airway protection. This study highlights differential mucosal and serum correlates of protection and how mucosal vaccines can durably prevent infection against SARS-CoV-2.

[Impact of systemic therapies on SARS-CoV-2 antibody seroprevalence in patients with immune-mediated diseases]

OBJECTIVE

To determine the seroprevalence of SARS-CoV-2 in patients with immune-mediated inflammatory diseases (IMID) treated with biologic (bDMARDs) or synthetic targeted disease-modifying antirheumatic drugs (tsDMARDs).

METHODS

An observational, descriptive, prospective and cross-sectional study of analytical prevalence analysis was conducted in patients with IMID with bDMARDs or tsDMARDs. Seroprevalence was compared by measuring immunoglobulinG (IgG) against SARS-CoV-2 between October/2020 and May/2021.

RESULTS

A total of 550 IMID's patients were studied, all of them on treatment with bDMARDs or tsDMARDs. The seroprevalence of the total patient group was 16% (88/550). Patients receiving therapy with tumor necrosis factor alpha inhibitors (TNFi) had a higher seroprevalence compared to other biologic and synthetic targeted therapies (OR: 1.792 [95%CI: 1.088-2.951]; P=.021). The influence on seroprevalence of concomitant use with b/tsDMARDs of conventional synthetic DMARDs (csDMARDs) was also analyzed. A lower seroprevalence was demonstrated in the group of patients treated with TNFi and methotrexate together, compared with those on TNFi monotherapy, 10.1 vs 24.1% (OR: 0.355 [95%CI: 0.165-0.764]; P=.006). No significant differences were found with the other DMARDs. Regarding IMIDs, no differences in seroprevalence were identified between the different disease groups.

CONCLUSION

Patients on treatment with TNFα inhibitors have better humoral response compared to the other b/tsDMARDs. However, when associated with methotrexate the seroprevalence decreases significantly.

Immune Response after Anti-SARS-CoV-2 mRNA Vaccination in Relation to Cellular Immunity, Vitamin D and Comorbidities in Hemodialysis Patients

In the global threat of SARS-CoV-2, individuals undergoing maintenance dialysis represent a vulnerable population with an increased risk of severe COVID-19 outcomes. Therefore, immunization against SARS-CoV-2 is an essential component of healthcare strategy for these patients. Existing data indicate that they tend to exhibit a reduced immune response to vaccines compared to the general population. Our study aimed to assess both humoral and cellular immune responses following two doses of an anti-SARS-CoV-2 mRNA vaccine, an ability to maintain adequate antibody titers over time, and potential relations with vitamin D, comorbidities and other factors in hemodialysis patients based on a single center experience. A total of 41/45 patients (91.1%) responded to the second dose of the anti-SARS-CoV-2 mRNA vaccine. The titer of anti-SARS-CoV-2 IgG class antibodies and levels of T cells three to four weeks after vaccination were lower in dialysis patients than in healthy controls. Antibodies titer in dialysis patients had a positive correlation with B lymphocytes and was related to cardiovascular diseases. The level of CD4+ cells had a negative correlation with hemodialysis vintage, as did the vitamin D level with post-vaccination seroconversion and decline in anti-SARS-CoV-2 antibodies titer during six months after vaccination. Hemodialysis patients had decreased amounts of CD4+ and CD8+ cells and lower levels of anti-SARS-CoV-2 antibodies than healthy controls. Therefore, chronic hemodialysis could lead to diminished cellular immunity and humoral immune response to the anti-SARS-CoV-2 mRNA vaccination and reduced protection from COVID-19. Comorbidity in cardiovascular diseases was associated with a lower level of specific anti-SARS-CoV-2 antibody titer. Vitamin D may be important in maintaining stable levels of anti-SARS-CoV-2 antibodies, while the duration of dialysis treatment could be one of the factors decreasing anti-SARS-CoV-2 antibody titer and determining lower CD4+ cell counts.

When Cell-Mediated Immunity after Vaccination Is Important

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COVID-19 Vaccination and Immunosuppressive Therapy in Immune-Mediated Inflammatory Diseases

The COVID-19 vaccination program has probably been the most complex and extensive project in history until now, which has been a challenge for all the people involved in the planning and management of this program. Patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressive therapy have required special attention, not only because of the particular haste in carrying out the process but also because of the uncertainty regarding their response to the vaccines. We now have strong scientific evidence that supports the hypothesis that immunosuppressive therapy inhibits the humoral response to vaccines against other infectious agents, such as influenza, pneumococcus and hepatitis B. This has led to the hypothesis that the same could happen with the COVID-19 vaccine. Several studies have therefore already been carried out in this area, suggesting that temporarily discontinuing the administration of methotrexate for 2 weeks post-vaccination could improve the vaccine response, and other studies with various immunosuppressive drugs are in the same line. However, the fact of withholding or interrupting immunosuppressive therapy when dealing with COVID-19 vaccination remains unclear. On this basis, our article tries to compile the information available on the effect of immunosuppressant agents on COVID-19 vaccine responses in patients with IMIDs and proposes an algorithm for the management of these patients.

Mucosal Adenoviral-vectored Vaccine Boosting Durably Prevents XBB.1.16 Infection in Nonhuman Primates

Waning immunity and continued virus evolution have limited the durability of protection from symptomatic infection mediated by intramuscularly (IM)-delivered mRNA vaccines against COVID-19 although protection from severe disease remains high. Mucosal vaccination has been proposed as a strategy to increase protection at the site of SARS-CoV-2 infection by enhancing airway immunity, potentially reducing rates of infection and transmission. Here, we compared protection against XBB.1.16 virus challenge 5 months following IM or mucosal boosting in non-human primates (NHP) that had previously received a two-dose mRNA-1273 primary vaccine regimen. The mucosal boost was composed of a bivalent chimpanzee adenoviral-vectored vaccine encoding for both SARS-CoV-2 WA1 and BA.5 spike proteins (ChAd-SARS-CoV-2-S) and delivered either by an intranasal mist or an inhaled aerosol. An additional group of animals was boosted by the IM route with bivalent WA1/BA.5 spike-matched mRNA (mRNA-1273.222) as a benchmark control. NHP were challenged in the upper and lower airways 18 weeks after boosting with XBB.1.16, a heterologous Omicron lineage strain. Cohorts boosted with ChAd-SARS-CoV-2-S by an aerosolized or intranasal route had low to undetectable virus replication as assessed by levels of subgenomic SARS-CoV-2 RNA in the lungs and nose, respectively. In contrast, animals that received the mRNA-1273.222 boost by the IM route showed minimal protection against virus replication in the upper airway but substantial reduction of virus RNA levels in the lower airway. Immune analysis showed that the mucosal vaccines elicited more durable antibody and T cell responses than the IM vaccine. Protection elicited by the aerosolized vaccine was associated with mucosal IgG and IgA responses, whereas protection elicited by intranasal delivery was mediated primarily by mucosal IgA. Thus, durable immunity and effective protection against a highly transmissible heterologous variant in both the upper and lower airways can be achieved by mucosal delivery of a virus-vectored vaccine. Our study provides a template for the development of mucosal vaccines that limit infection and transmission against respiratory pathogens.

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Cancer/Testis Antigens as Targets for RNA-Based Anticancer Therapy

In the last few decades, RNA-based drugs have emerged as a promising candidate in the treatment of various diseases. The introduction of messenger RNA (mRNA) as a vaccine or therapeutic agent enables the production of almost any functional protein/peptide. The key to applying RNA therapy in clinical trials is developing safe and effective delivery systems. Exosomes and lipid nanoparticles (LNPs) have been exploited as promising vehicles for drug delivery. This review discusses the feasibility of exosomes and LNPs as vehicles for mRNA delivery. Cancer/testis antigens (CTAs) show restricted expression in normal tissues and widespread expression in cancer tissues. Many of these CTAs show expression in the sera of patients with cancers. These characteristics of CTAs make them excellent targets for cancer immunotherapy. This review summarizes the roles of CTAs in various life processes and current studies on mRNAs encoding CTAs. Clinical studies present the beneficial effects of mRNAs encoding CTAs in patients with cancers. This review highlight clinical studies employing mRNA-LNPs encoding CTAs.

BA.1/BA.5 Immunogenicity, Reactogenicity, and Disease Activity after COVID-19 Vaccination in Patients with ANCA-Associated Vasculitis: A Prospective Observational Cohort Study

Emerging omicron subtypes with immune escape lead to inadequate vaccine response with breakthrough infections in immunocompromised individuals such as Anti-neutrophil Cytoplasmic Antibody (ANCA)-associated vasculitis (AAV) patients. As AAV is considered an orphan disease, there are still limited data on SARS-CoV-2 vaccination and prospective studies that have focused exclusively on AAV patients are lacking. In addition, there are safety concerns regarding the use of highly immunogenic mRNA vaccines in autoimmune diseases, and further studies investigating reactogenicity are urgently needed. In this prospective observational cohort study, we performed a detailed characterization of neutralizing antibody responses against omicron subtypes and provided a longitudinal assessment of vaccine reactogenicity and AAV disease activity. Different vaccine doses were generally well tolerated and no AAV relapses occurred during follow-up. AAV patients had significantly lower anti-S1 IgG and surrogate-neutralizing antibodies after first, second, and third vaccine doses as compared to healthy controls, respectively. Live-virus neutralization assays against omicron subtypes BA.1 and BA.5 revealed that previous SARS-CoV-2 vaccines result in an inadequate neutralizing immune response in immunocompromised AAV patients. These data demonstrate that new vaccination strategies including adapted mRNA vaccines against epitopes of emerging variants are needed to help protect highly vulnerable individuals such as AAV patients.

Five doses of the mRNA vaccination potentially suppress ancestral-strain stimulated SARS-CoV2-specific cellular immunity: a cohort study from the Fukushima vaccination community survey, Japan

The bivalent mRNA vaccine is recommended to address coronavirus disease variants, with additional doses suggested for high-risk groups. However, the effectiveness, optimal frequency, and number of doses remain uncertain. In this study, we examined the long-term cellular and humoral immune responses following the fifth administration of the mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in patients undergoing hemodialysis. To our knowledge, this is the first study to monitor long-term data on humoral and cellular immunity dynamics in high-risk populations after five doses of mRNA vaccination, including the bivalent mRNA vaccine. Whereas most patients maintained humoral immunity throughout the observation period, we observed reduced cellular immune reactivity as measured by the ancestral-strain-stimulated ELISpot assay in a subset of patients. Half of the individuals (50%; 14/28) maintained cellular immunity three months after the fifth dose, despite acquiring humoral immunity. The absence of a relationship between positive controls and T-Spot reactivity suggests that these immune alterations were specific to SARS-CoV-2. In multivariable analysis, participants aged ≥70 years showed a marginally significant lower likelihood of having reactive results. Notably, among the 14 individuals who received heterologous vaccines, 13 successfully acquired cellular immunity, supporting the effectiveness of this administration strategy. These findings provide valuable insights for future vaccination strategies in vulnerable populations. However, further research is needed to evaluate the involvement of immune tolerance and exhaustion through repeated vaccination to optimize immunization strategies.