Search Results (243)

Background and Clinical Significance: The COVID-19 pandemic led to the rapid development of effective vaccination strategies. Although COVID-19 vaccines are generally safe, rare hematological adverse events have been reported, most prominently vaccine-induced immune thrombotic thrombocytopenia (VITT). Isolated cases of autoimmune cytopenias and bone marrow failure syndromes following COVID-19 vaccination have also been described. Case Presentation: We report the case of an 80-year-old male who developed subacute-onset severe normocytic anemia with reticulocytopenia and mild leukopenia following heterologous COVID-19 vaccination with ChAdOx1 nCoV-19 (AstraZeneca) and BNT162b2 (Pfizer–BioNTech). Seven days after the second vaccination, mild anemia was detected, progressing over the following weeks to symptomatic anemia requiring hospitalization. Extensive diagnostic evaluation revealed no evidence of hemolysis, nutritional deficiency, autoimmune disease, or viral infection, including SARS-CoV-2 and Parvovirus B19. Bone marrow examination demonstrated an erythroid maturation arrest at the proerythroblast stage, resembling a pure red cell aplasia (PRCA)-like pattern. Cytogenetic and molecular analyses excluded myelodysplastic syndromes. Treatment with erythropoietin resulted in complete hematologic recovery. Conclusions: This case suggests that, in rare instances, COVID-19 vaccination may be temporally associated with transient suppression of erythropoiesis. Further studies are required to elucidate underlying mechanisms and to guide diagnosis and management. Full article

Background/Objectives: Waning immunity after primary COVID-19 vaccination supports evaluation of additional doses. HXP-GPOVac is an egg-based, inactivated Newcastle disease virus (NDV)-vectored vaccine expressing a prefusion-stabilized SARS-CoV-2 HexaPro spike antigen. We evaluated the safety, tolerability, and immunogenicity of a single additional 10 µg dose of HXP-GPOVac administered to adults previously primed with two doses of either HXP-GPOVac or BNT162b2. Methods: Study GPO NDV-HXP-S 203 was an open-label phase II extension enrolling adults (18–75 years) who previously completed a two-dose primary series in Study 202 with either HXP-GPOVac or BNT162b2 (Pfizer–BioNTech; Comirnaty). All participants received a single additional 10 µg intramuscular dose of HXP-GPOVac ≥ 6 months after their second primary dose. Solicited local/systemic adverse events (AEs) were recorded for 7 days, unsolicited AEs through Day 28, and serious AEs (SAEs) and adverse events of special interest (AESIs) throughout follow-up. Neutralizing antibody titers (pseudovirus 50% neutralization titer, NT₅₀) and anti-spike IgG (BAU/mL) were assessed pre-dose (Day 1) and post-vaccination through 12 months; a predefined subset underwent IFN-γ and IL-5 ELISpot. SARS-CoV-2 infection during follow-up was assessed using anti-nucleocapsid (anti-N) IgG. Symptomatic COVID-19 was identified through symptom-reported, symptom-triggered RT-PCR testing; sequencing was performed when feasible. Results: All 219 participants received HXP-GPOVac (167 primed with HXP-GPOVac and 52 with BNT162b2). Any solicited local reaction occurred in 22.2% (37/167) of HXP-GPOVac-primed and 26.9% (14/52) of BNT162b2-primed participants; any solicited systemic reaction occurred in 10.8% (18/167) and 13.5% (7/52), respectively. No vaccine-related unsolicited AEs or AESIs were reported. Three deaths occurred during the 12-month follow-up; one (a sudden cardiac death in an HXP-GPOVac-primed participant) was assessed by the safety medical team as possibly related to vaccination, and two were assessed as not related. Neutralizing antibody GMTs increased from 46.33 at baseline to 1569.04 at Day 15 in HXP-GPOVac-primed participants and from 77.25 to 841.34 in BNT162b2-primed participants; corresponding SCRs were 78.8% and 76.9%. Anti-spike IgG GMCs increased from 48.79 to 1480.14 BAU/mL and from 194.48 to 1547.88 BAU/mL, respectively. Responses declined over time but remained above baseline through 12 months. In the cellular immunity subset, post-vaccination IFN-γ responses increased, with comparatively modest IL-5 responses and no pattern suggestive of Th2 predominance. Conclusions: A single additional dose of HXP-GPOVac administered ≥6 months after primary vaccination with HXP-GPOVac or BNT162b2 was generally well tolerated and elicited robust recall humoral responses, with supportive findings of cellular immunity. Trial registration: Thai Clinical Trials Registry, TCTR20230213001. Full article

Background: The dynamics of humoral immune responses following primary and booster COVID-19 vaccinations are crucial to understand in order to optimize vaccination strategies. This study evaluates the magnitude and durability of SARS-CoV-2-specific IgG antibody responses across different vaccines in a large cohort of Bangladeshi adults. Methods: A total of 6300 adults from nine hospitals across eight divisions of Bangladesh were enrolled. Participants received two primary doses of either ChAdOx1 nCoV-19 (Covishield, Serum Institute of India, n = 2855), mRNA-1273 (Moderna, n = 578), BNT162b2 (Pfizer-BioNTech, n = 121), or Vero-cell-inactivated (Sinopharm, n = 2746) vaccines. Booster doses were administered at one-year intervals post-primary vaccination. SARS-CoV-2 spike receptor-binding domain (RBD)-specific IgG antibody responses were measured by ELISA using serum from vaccinees at multiple time points after two primary and two booster doses. Results: A total of 3745 individuals received booster 1 (third dose), with 59% receiving heterologous boosters (a different vaccine regimen than the primary doses). Only 5.5% (n = 347) of participants received a second booster one year after the first booster (among them, 99% received BNT162b2). Our results suggest that heterologous boosters with the mRNA vaccine induced higher IgG levels than homologous boosters for individuals who received primary vaccination with adenovirus vector-based ChAdOx1 nCoV-19 or a Vero-cell-inactivated vaccine. However, in those who initially received the mRNA-based vaccine, both homologous and heterologous boosters produced comparable IgG responses. Among all vaccine types, booster immunization with the Vero-cell-inactivated vaccine induced the lowest antibody responses. Longitudinal analysis demonstrated significantly high IgG levels over the 12 months following the first booster (p < 0.0001); however, IgG levels declined significantly after the second booster dose (fourth dose). Conclusions: Heterologous boosting strategies, particularly those involving mRNA vaccines, elicit stronger and more sustained IgG responses compared to a homologous booster. However, antibody waning after the second booster highlights the need for continued monitoring and potential additional vaccine strategies. Full article

Background/Objectives: Guillain–Barré syndrome (GBS) is a rare but serious immune-mediated neurological disorder monitored as an adverse event of special interest during the COVID-19 pandemic. This study aimed to estimate the incidence of GBS following COVID-19 vaccination and SARS-CoV-2 infection and to compare the risk by vaccine platform. Methods: We conducted a population-based retrospective cohort study using data from the Valencia Health System Integrated Database (Spain) between January 2018 and March 2022. Two cohorts were defined: individuals receiving COVID-19 vaccines (mRNA-based vaccines (BNT162b2 [Pfizer–BioNTech] and mRNA-1273 [Moderna]) or non-virus-vectored (NVV) adenoviral vector-based vaccines (ChAdOx1-S [AstraZeneca] and Ad26.COV2.S [Janssen])) and individuals with laboratory-confirmed SARS-CoV-2 infection. Incident GBS cases were identified within a predefined 42-day risk window following vaccination or infection. Incidence rates were calculated per 100,000 vaccine doses administered or SARS-CoV-2 infections. Results: Among 5,109,919 individuals, 4,270,610 received at least one COVID-19 vaccine dose and 920,643 experienced at least one SARS-CoV-2 infection. A total of 69 GBS cases occurred within 42 days following vaccination (incidence: 0.67 per 100,000 doses), whereas 21 cases occurred after infection (incidence: 2.20 per 100,000 infections). Incidence was lower after mRNA-based vaccines (0.55 per 100,000 doses) than after NVV vaccines (1.57 per 100,000 doses). Conclusions: This study confirms that GBS occurrence following vaccination is rare. The incidence is lower among individuals who received mRNA vaccines compared to those who received NVV vaccines. Moreover, GBS appears to be more frequent after a COVID-19 infection than after vaccination. These findings highlight the importance of integrating pharmacoepidemiological analyses with pharmacovigilance data to contextualize rare but serious adverse events. Full article

COVID-19 mRNA vaccines activate type I interferon pathways and in genetically or immunologically predisposed individuals may trigger autoimmune responses, including autoantibodies against melanoma differentiation-associated protein 5 (MDA5). Although cases of dermatomyositis (DM), particularly anti-MDA5-positive DM, have been increasingly reported after SARS-CoV-2 vaccination, its clinical spectrum and management remain incompletely defined. We conducted a narrative review of the literature on post-vaccination dermatomyositis, focusing on clinical features, autoantibody profiles, therapeutic approaches, and outcomes. The review was enriched by the inclusion of a new case: a 60-year-old woman who developed anti-MDA5-positive dermatomyositis two weeks after receiving her fourth dose of the BNT162b2 (Pfizer/BioNTech) vaccine. She presented predominantly with cutaneous and articular manifestations in the absence of interstitial lung disease. Treatment with oral prednisone, intravenous alprostadil, and the Janus kinase inhibitor tofacitinib resulted in marked clinical improvement. This case, together with the literature review, illustrates both typical and atypical presentations of vaccine-associated anti-MDA5 DM, highlights diagnostic challenges without lung involvement, and suggests JAK inhibition as a potential therapeutic option, contributing to a more comprehensive understanding of post-vaccination dermatomyositis. Full article

Background: In 2019, a new virus caused by SARS-CoV-2, called COVID-19, spread throughout the world, causing a pandemic state. As the pandemic progressed and cases continued to increase, safe vaccines were developed for the entire population. In Brazil, AstraZeneca^® (ChAdOx1-S) and Pfizer^® (BNT162b2) vaccines were among those administered to the population. Objectives: The objective of this study was to analyze whether immunoglobulin G (IgG) is produced for COVID-19 in individuals immunized with two doses of AstraZeneca (ChAdOx1-S) and Pfizer (BNT162b2) vaccines and to evaluate several parameters in order to understand how our bodies respond to this immunization. Methods: The study involved the participation of 120 individuals: 49 in the control group, 44 vaccinated with the AstraZeneca vaccine, and 27 the vaccinated with Pfizer vaccine. Results: Hematological, biochemical, inflammatory, and oxidant/antioxidant parameters and the production of IgG antibodies were analyzed. An increase in some inflammatory parameters was observed in vaccinated individuals, which may have been caused by an immune reaction after vaccination. In terms of hematological parameters, the changes caused by vaccination appear to be transient and quickly resolved after immunization. In terms of biochemical parameters, an increase in IgG antibodies was observed in the group vaccinated with the Pfizer^® vaccine; however, the AstraZeneca^® and control groups also produced IgG, although to a lesser extent. In terms of the remaining parameters, there was little change after vaccination. Regarding the levels of oxidants/antioxidants, it was observed that there was a compensation by antioxidants due to the increase in oxidant parameters, which may act as corrective mechanism. Conclusions: Both the AstraZeneca^® and Pfizer^® vaccines induced anti-SARS-CoV-2 IgG production, accompanied by inflammatory, hematological, and oxidative changes. Full article

Background/Objectives: Paediatricians’ recommendations influence parental decisions to vaccinate their children. On 19 January 2022, the World Health Organization authorized the Pfizer-BioNTech COVID-19 vaccine (BNT162b2) under Emergency Use Listing for children under 12 years as a measure to mitigate disease spread and direct protection for children with underlying conditions. We assessed knowledge, attitudes, and practices (KAP) of Palestinian paediatricians regarding COVID-19 vaccination for children under 12 years and identified factors affecting support for vaccination. Methods: From 1 October to 8 November 2023, we surveyed paediatricians across the West Bank using structured telephone interviews. We collected data on sociodemographic characteristics and KAP regarding COVID-19 vaccination and calculated KAP scores from eight, nine, and nine items, respectively, with total scores categorized as poor/moderate/good. We performed bivariable and multivariable analyses to identify factors associated with paediatricians supporting COVID-19 vaccination for children under 12 years. Results: Of the 367 eligible paediatricians, 323 (88%) responded; the median age was 51 years (range: 28–70); 27% supported COVID-19 vaccination for children. Mean scores for knowledge (range 0–8), attitude (0–9), and practice (0–9) were 3.0 ± 2.1, 3.9 ± 2.4, and 4.0 ± 1.7, respectively. The mean overall KAP score (0–26) was 11 ± 4.8. Safety and efficacy concerns and lack of long-term data were the main reasons for hesitancy. Higher knowledge scores (PR = 1.8, 95% CI: 1.3–2.5, p = 0.001) and positive attitudes (PR = 1.6, 95% CI: 1.1–2.3, p = 0.01) were significantly associated with paediatricians’ support for vaccination. After adjustment for other factors, participants with regular continuing medical education attendance (aPR = 1.4, 95% CI: 1.0–2.6, p = 0.045), trusting WHO recommendations (aPR = 3.1, 95% CI: 1.4–7.8, p = 0.047), having a positive attitude score (aPR = 1.3, 95% CI: 0.4–4.4, p = 0.041), and a good total KAP score (aPR = 1.1, 95% CI: 1.0–1.2, p = 0.044) supported COVID-19 vaccination for children. Conclusions: Support for COVID-19 vaccination among Palestinian paediatricians was low, associated with their knowledge, attitudes, and trust in health authorities. The revised WHO recommendations from 10 November 2023, decreasing the priority of vaccinating healthy children, could influence the opinion of paediatricians. However, the low support for COVID-19 vaccinations could affect the performance of other vaccination programmes and should be carefully addressed through targeted education. Full article

Background: Numerous studies have proved the efficacy of vaccination in reducing Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission and the coronavirus disease (COVID-19) burden. However, even though the COVID-19 vaccination coverage is high for primary doses, a booster dose is needed to sustain protection. Continuing our previous research, this study evaluates the immunogenicity and safety of full and half doses of two COVID-19 booster vaccines, ChAdOx1-S (AstraZeneca) and BNT162b2 (Pfizer-BioNTech), in individuals primed with ChAdOx1-S. Methods: This study was an observer-blind randomized controlled trial to evaluate the immunogenicity and safety of half and full doses of two COVID-19 booster vaccine types, BNT162b2 and ChAdOx1-S, among fully vaccinated, ChAdOx1-S-primed individuals in Jakarta, Indonesia. A total of 329 participants were randomized to receive either full or half doses of the booster vaccines, namely the ChAdOx1-S and BNT162b2 COVID-19 vaccines. Immunogenicity was assessed through SARS-CoV-2 antibody titers and neutralizing antibodies (NAbs) at 28 days post-booster, while safety was monitored via adverse event reporting. Results: The results showed that both vaccines demonstrated increased geometric mean titers (GMTs) post-booster. In the ChAdOx1-S booster group, at the baseline visit (day 0) and third visit (day 28), no statistically significant differences in GMT between the half- and full-dose groups were observed (p = 0.970 and 0.539, respectively). In the BNT162b2 group, no statistically significant difference was noted at the baseline visit, while the full dose was higher than the half dose at 28 days (Day 28, p = 0.011). Surrogate virus neutralization tests (sVNTs) and NAbs assays also revealed no significant differences between the half and full dose groups for both the Wuhan strain and the Delta variant. The BNT162b2 group compared to the ChAdOx1-S group revealed a statistically significant increase in IgG levels compared to ChAdOx1-S, with p-values of <0.001 and <0.001 for the half dose and full dose, respectively. This was also reflected in the NAbs test results, where BNT162b2 showed significantly higher levels against both the Wuhan strain and Delta variant. Adverse events were predominantly mild: 79.6% (n = 86/108) in the ChAdOx1-S full-dose group, 75.4% (n = 43/57) in the ChAdOx1-S half-dose group, 84.2% (n = 101/120) in the BNT162b2 full-dose group, and 92.6% (n = 88/95) in the BNT162b2 half-dose group, with pain at the injection site being the most common local reaction and myalgia and headache the most frequent systemic reactions. One serious adverse event was reported, assessed as unrelated to the vaccine. Conclusions: This study confirms that half doses of ChAdOx1-S and BNT162b2 are as immunogenic and safe as full doses, and a heterologous booster is more immunogenic than a homologous booster. Full article

Background: In the Kingdom of Saudi Arabia, various COVID-19 vaccines were administered during the pandemic. However, region-specific real-word comparative data on their immunogenicity remain limited. This study aimed to assess the serological responses to Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and AstraZeneca (ChAdOx1 nCoV-19) vaccines in a diverse population living in KSA. Methods: This observational study included 236 adults recruited from vaccination sites in Riyadh. Participants provided serum samples at predefined intervals: before the first dose, after the first dose, after the second dose, and post-vaccination infection (if applicable). IgG and neutralising antibodies were quantified using ELISA assays. Demographic and vaccination data, and their associations with antibody responses, were evaluated. Results: At baseline, 75.4% of participants were positive for SARS-CoV-2 IgG, suggesting high prior exposure. Marked incremental increases in IgG levels were observed after each vaccine dose. Both Moderna and Pfizer elicited stronger responses, with Pfizer inducing the strongest early response and Moderna achieving the highest overall titres. Among IgG-positive individuals, neutralising antibodies were detected in 98.1%. There were no statistically significant differences by age or gender, although males tended to show higher mean titres. Heterologous vaccine schedules induced comparable or enhanced immunogenicity relative to homologous schedules, supporting their use in flexible immunisation strategies. Conclusions: All COVID-19 vaccines administered in Saudi Arabia elicited robust antibody responses, particularly the mRNA-based vaccines. Our findings support their continued use and justify varied vaccination approaches, including mix-and-match booster strategies, to enhance community immunity. Full article

We aimed to explore SARS-CoV-2 evolution during in vitro neutralisation using next generation sequencing, and to determine whether sera from individuals immunised with two doses of the Pfizer-BioNTech vaccine (BNT162b2) were as effective at neutralising the variant of concern (VOC) Delta (B.1.617.2) compared to the earlier lineages Beta (B.1.351) and wild-type (A.2.2) virus. Using a live-virus SARS-CoV-2 neutralisation assay in Vero E6 cells, we determined neutralising antibody titres (nAbT) against three SARS-CoV-2 strains (wild type, Beta, and Delta) in 14 participants (vaccine-naïve (n = 2) and post-second dose of BNT162b2 vaccination (n = 12)), median age 45 years [IQR 29–65]; the median time after the second dose was 21 days [IQR 19–28]. The determination of nAbT was based on cytopathic effect (CPE) and in-house quantitative reverse transcriptase real-time quantitative polymerase chain reaction (RT-qPCR) to confirm SARS-CoV-2 replication. A total of 110 representative samples including inoculum, neutralisation breakpoints at 72 h, and negative and positive controls underwent genome sequencing. By integrating live-virus neutralisation assays with deep sequencing, we characterised both functional antibody responses and accompanying viral genetic changes. There was a reduction in nAbT observed against the Delta and Beta VOC compared with wild type, 4.4-fold (p ≤ 0.0006) and 2.3-fold (p = 0.0140), respectively. Neutralising antibodies were not detected in one vaccinated immunosuppressed participant and the vaccine-naïve participants (n = 2). The highest nAbT against the SARS-CoV-2 variants investigated was obtained from a participant who was vaccinated following SARS-CoV-2 infection 12 months prior. Limited consensus level mutations occurred in the various SARS-CoV-2 lineage genomes during in vitro neutralisation; however, consistent minority allele frequency variants (MFV) were detected in the SARS-CoV-2 polypeptide, spike (S), and membrane protein. Findings from countries with high COVID-19 incidence may not be applicable to low-incidence settings such as Australia; as seen in our cohort, nAbT may be significantly higher in vaccine recipients previously infected with SARS-CoV-2. Monitoring viral evolution is critical to evaluate the impact of novel SARS-CoV-2 variants on vaccine effectiveness, as mutational profiles in the sub-consensus genome could indicate increases in transmissibility and virulence or suggest the development of antiviral resistance. Full article

Background: While mRNA vaccines effectively limit hospitalization and severe COVID-19 disease, the precise early innate immune mechanisms associated with their efficacy and reactogenicity remain underexplored. The identification of innate immune correlates prior to vaccination could provide mechanistic insights and potentially predict responses. Methods: We developed an in vitro model to study the innate immune activation of pre-vaccination peripheral blood mononuclear cells (PBMCs) collected from participants enrolled in a well-characterized COVID-19 BioNTech/Pfizer BNT162b2 vaccine (BNT162b2 vaccine) cohort. Pre-vaccination PBMCs were stimulated with empty lipid nanoparticle (LNP), mRNA-LNP, or Toll-like receptor (TLR) agonists. Using multiparameter spectral flow cytometry, we analyzed the baseline immune state, innate responsiveness to stimuli, and cytokine profiles of study participants. These pre-vaccination in vitro results were analyzed for correlations with post-vaccination symptoms and spike-specific IgG responses. Results: Baseline dendritic cell (DC) states inversely correlated with the magnitude of symptoms following BNT162b2 vaccination. Heightened conventional (cDC) and weaker plasmacytoid DC (pDC) responses to RNA stimuli correlated with the magnitude of an acute IgG response. IgG durability modestly correlated with a lower pDC state but higher cDC2 and monocyte baseline states and inversely correlated with TLR3 agonist responsiveness. Conclusions: The pre-vaccination assessment of innate immune function and resting states can be used to fit models potentially predictive of immunogenicity and reactogenicity to BNT162b2 vaccination. Pre-vaccination DC states may influence reactogenicity, while the response to RNA may impact antibody responses. Our data suggest that pre-vaccination assessment offers insights into the innate mechanisms driving mRNA vaccine responses and has predictive potential. Full article

Background and Clinical Significance: The occurrence of cerebral venous sinus thrombosis (CVST), both with or without thrombocytopenia, following COVID-19 vaccination, is well documented and more common in recipients of vector vaccines. Cases of CVST following immunization with the COVID-19 messenger RNA (mRNA) vaccine are rare; most of these cases occur within 28 days of the first dose of the vaccine. Case Presentation: We present the case of a 38-year-old male with a history of two episodes of deep vein thrombosis in the lower limbs, but without a specific thrombophilic condition, who developed CVST 13 days after the second dose of the Pfizer/BioNTech BNT162b2 vaccine. He suffered from diffuse tension-type headache of progressively increasing intensity, and his objective neurological findings were normal. Magnetic resonance venography showed thrombosis of the transverse and right sigmoid sinuses, and magnetic resonance imaging (MRI) of the brain revealed no cerebral infarction. Two months later, a follow-up MR venography showed partial recanalization of the affected sinuses, and a brain MRI showed no infarction. Conclusions: Given the temporal sequence and the absence of other possible causes, we speculate that the second dose of the COVID-19 BNT162b2 vaccine may have triggered the development of CVST. Full article

Objective: To evaluate the association between the BNT162b2 (Pfizer-BioNTech^®) coronavirus disease vaccine and new-onset anterior uveitis. Methods: A retrospective case control study of patients admitted and diagnosed with new-onset acute anterior uveitis, and matched controls admitted for other reasons (1:3 ratio), was completed. Rates of exposure to the BNT162b2 vaccine were compared between groups, and odds ratios for exposure to the vaccine were calculated. A secondary analysis of the overall number of patients with new-onset anterior uveitis in the six preceding years was conducted. This study was conducted in one academic center in Israel. Results: A total of 16 patients were admitted for acute anterior uveitis during the study period. Of the 16 cases, 11 (69%) received the first dose of the BNT162b2 vaccine prior to presentation and 8 (50%) also received the second dose. This compares to 39 (81.2%) in the control group. The odds ratio for exposure to the vaccine among cases was 0.508 (95% confidence interval 0.141–1.829, p = 0.300). Compared with preceding years, the rate of cases diagnosed with acute anterior uveitis in 2021 was similar to the six preceding years (mean 11.8 ± 3.4 cases). Conclusions: In this case control study and comparison with preceding years, we found no evidence to suggest an association between vaccination with the BNT162b2 (Pfizer-BioNTech^®) COVID-19 vaccine and new-onset acute anterior uveitis. Full article

Case Report: We report a case of a 37-year-old female with kidney transplant, who was admitted at our hospital due to worsening renal function, nephrotic proteinuria, and anemia developed 21 days after the second dose of BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). Laboratory tests revealed hemolytic anemia, thrombocytopenia, and acute kidney injury. Given the clinical picture of Thrombotic Micro-angiopathy (TMA) and severe renal impairment, plasma exchange (PEX) and dialysis were immediately started. Laboratory workup showed low C3 and C4 levels, normal activity of ADAMTS13, and the absence of anti-factor H antibodies. Molecular biology investigations revealed a heterozygous variant in exon 22 (SCR20) of the CFH gene (c.3628C>T; p.Arg1210Cys) described as an atypical Hemolytic Uremic Syndrome (aHUS) causative mutation. Our patient completed two sessions of PEX followed by eculizumab treatment with hematological improvement but no recovery of renal function. This is the first reported case of aHUS triggered by SARS-CoV-2 vaccination in a kidney transplant patient without recovery of renal function. Conclusion: Although rare, clinicians should be aware of possible nephrological complications that may appear after vaccination. Full article

Objective: To evaluate the humoral response to and impact of SARS-CoV-2 vaccination in patients with systemic lupus erythematosus in a multicenter cohort design. Methods: Data for this analysis were obtained from the Study of Safety, Effectiveness and Duration of Immunity after Vaccination against SARS-CoV-2 in Patients with Immune-Mediated Inflammatory Diseases (SAFER), a prospective, multicenter, phase IV, real-world study conducted across different regions of Brazil from June/2021 to March/2024. Patients aged >18 years with systemic lupus erythematosus (SLE) who received any one of the SARS-CoV-2 vaccines approved by the Brazilian health regulatory agency (CoronaVac [inactivated SARS-CoV-2 vaccine], ChAdOx-1 [AstraZeneca], or BNT162b2 [Pfizer-BioNTech]) were included. Immunogenicity was assessed in pre- and post-vaccination blood samples, and patients were monitored in person and remotely for the occurrence and severity of COVID-19. Results: Two hundred and thirty-five patients with SLE who had completed their vaccination schedules (two doses + booster dose) were included in this study. Most patients were female (89.3%) and had low disease activity or were in remission (72.4%); the majority were also on some form of immunosuppressive therapy (58.1%). One hundred and sixteen patients received two doses of CoronaVac followed by one dose of BNT162b2 (Pfizer-BioNTech) vaccine, eighty-seven received two doses of ChAdOx1-S (AstraZeneca) followed by one dose of BNT162b2 (Pfizer-BioNTech) vaccine, and thirty-two received three doses of BNT162b2 (Pfizer-BioNTech) vaccine. Twenty-eight cases of COVID-19, none meeting criteria for severe COVID-19, were recorded in patients with respiratory symptoms after the second dose of a SARS-CoV-2 vaccine. Regarding immunogenicity, an increase in seroconversion rate was observed following consecutive vaccine doses, with no difference between vaccination schedules, reaching 97.57% seropositivity after a booster dose. The geometric mean IgG titers differed between the different vaccination schedules after the first and the second vaccine dose, being lowest for the CoronaVac-based schedule, but titers were similar after the administration of a booster dose. Conclusion: In patients with SLE, SARS-CoV-2 vaccines are immunogenic, inducing a robust humoral response. No severe outcomes associated with death or hospitalization were found in the evaluated patient sample. Complete vaccination schedules including a booster dose induced higher humoral responses than incomplete schedules, especially in patients initially immunized with an inactivated virus vaccine schedule and those with a suboptimal humoral response. Full article