Vaccine-induced immune thrombotic thrombocytopenia

A scoping review of active, participant centred, digital adverse events following immunization (AEFI) surveillance of WHO approved COVID-19 vaccines: A Canadian immunization Research Network study

This scoping review examines the role of digital solutions in active, participant-centered surveillance of adverse events following initial release of COVID-19 vaccines. The goals of this paper were to examine the existing literature surrounding digital solutions and technology used for active, participant centered, AEFI surveillance of novel COVID-19 vaccines approved by WHO. This paper also aimed to identify gaps in literature surrounding digital, active, participant centered AEFI surveillance systems and to identify and describe the core components of active, participant centered, digital surveillance systems being used for post-market AEFI surveillance of WHO approved COVID-19 vaccines, with a focus on the digital solutions and technology being used, the type of AEFI detected, and the populations under surveillance. The findings highlight the need for customized surveillance systems based on local contexts and the lessons learned to improve future vaccine monitoring and pandemic preparedness.

How We Interpret Thrombosis with Thrombocytopenia Syndrome?

Platelets play an important role in hemostasis, and a low platelet count usually increases the risk of bleeding. Conditions in which thrombosis occurs despite low platelet counts are referred to as thrombosis with thrombocytopenia syndrome, including heparin-induced thrombocytopenia, vaccine-induced immune thrombotic thrombocytopenia, paroxysmal nocturnal hemoglobinuria, antiphospholipid syndrome, thrombotic microangiopathy (TMA), and disseminated intravascular coagulation. TMA includes thrombotic thrombocytopenic purpura, Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (HUS), and atypical HUS. Patients with these pathologies present with thrombosis and consumptive thrombocytopenia associated with the activation of platelets and the coagulation system. Treatment varies from disease to disease, and many diseases have direct impacts on mortality and organ prognosis if therapeutic interventions are not promptly implemented. Underlying diseases and the results of physical examinations and general laboratory tests as part of a thorough workup for patients should promptly lead to therapeutic intervention before definitive diagnosis. For some diseases, the diagnosis and initial treatment must proceed in parallel. Utilization of not only laboratory tests but also various scoring systems is important for validating therapeutic interventions based on clinical information.

A study on the side effects caused by the Pfizer/BioNTech COVID-19 vaccine: Focus on IgG antibodies and serological biomarkers

Introduction

The SARS-CoV-2 pandemic that spread swiftly is now a major global public health issue. Vaccines are currently being distributed in an effort to limit the viral transmission and mortality. The aim of the study was monitoring of both safety and efficacy in determining the overall effectiveness of the vaccine and identifying any potential safety concerns.

Material and methods

A retrospective, cross-sectional study employing a validated 13-item structured questionnaire divided into two sections was performed between March 2022 and September 2022. Different post-vaccination side effects (SE) according to symptoms severity in terms of age and sex for participants were reported. Additionally, some pertinent serological assays for participants' post-vaccinations were investigated.

Results

A total of 502 participants (male: 262, female: 240) with comorbidity (healthy: 258, morbid: 244) who received two Pfizer/BioNTech mRNA vaccine doses were included. Importantly, second dose (D2) vaccination was associated with significantly more SE than single dose (D1) vaccination (p < 0.0001). In D1 vaccination injection site pain (ISP) (45%), followed by equal proportions of headache and fever (40%) were the most common vaccine SE, while in D2 vaccination, ISP (66%) and nausea (57%) were reported. In all, 97% (p < 0.0001) of participants were IgG antibody positive at D2 vaccination. Similarly, serum CR protein level was elevated significantly (p < 0.0001) corresponding to the severity of SE between D1 and D2. Significant differences in IgG concentration were found between D1 and D2 vaccination in different gender and age groups (p < 0.0001).

Conclusions

In light of the extensive data from this study, it is evident that mRNA vaccines, particularly the Pfizer/BioNTech vaccine, have proven to be highly safe and effective in mitigating the impact of the SARS-CoV-2 pandemic.

Mucosal immunization with a low-energy electron inactivated respiratory syncytial virus vaccine protects mice without Th2 immune bias

The respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infections associated with numerous hospitalizations. Recently, intramuscular (i.m.) vaccines against RSV have been approved for elderly and pregnant women. Noninvasive mucosal vaccination, e.g., by inhalation, offers an alternative against respiratory pathogens like RSV. Effective mucosal vaccines induce local immune responses, potentially resulting in the efficient and fast elimination of respiratory viruses after natural infection. To investigate this immune response to an RSV challenge, low-energy electron inactivated RSV (LEEI-RSV) was formulated with phosphatidylcholine-liposomes (PC-LEEI-RSV) or 1,2-dioleoyl-3-trimethylammonium-propane and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DD-LEEI-RSV) for vaccination of mice intranasally. As controls, LEEI-RSV and formalin-inactivated-RSV (FI-RSV) were used via i.m. vaccination. The RSV-specific immunogenicity of the different vaccines and their protective efficacy were analyzed. RSV-specific IgA antibodies and a statistically significant reduction in viral load upon challenge were detected in mucosal DD-LEEI-RSV-vaccinated animals. Alhydrogel-adjuvanted LEEI-RSV i.m. showed a Th2-bias with enhanced IgE, eosinophils, and lung histopathology comparable to FI-RSV. These effects were absent when applying the mucosal vaccines highlighting the potential of DD-LEEI-RSV as an RSV vaccine candidate and the improved performance of this mucosal vaccine candidate.

Characterization and trajectories of hematological parameters prior to severe COVID-19 based on a large-scale prospective health checkup cohort in western China: a longitudinal study of 13-year follow-up

BACKGROUND

The relaxation of the "zero-COVID" policy on Dec. 7, 2022, in China posed a major public health threat recently. Complete blood count test was discovered to have complicated relationships with COVID-19 after the infection, while very few studies could track long-term monitoring of the health status and identify the characterization of hematological parameters prior to COVID-19.

METHODS

Based on a 13-year longitudinal prospective health checkup cohort of ~ 480,000 participants in West China Hospital, the largest medical center in western China, we documented 998 participants with a laboratory-confirmed diagnosis of COVID-19 during the 1 month after the policy. We performed a time-to-event analysis to explore the associations of severe COVID-19 patients diagnosed, with 34 different hematological parameters at the baseline level prior to COVID-19, including the whole and the subtypes of white and red blood cells.

RESULTS

A total of 998 participants with a positive SARS-CoV-2 test were documented in the cohort, 42 of which were severe cases. For white blood cell-related parameters, a higher level of basophil percentage (HR = 6.164, 95% CI = 2.066-18.393, P = 0.001) and monocyte percentage (HR = 1.283, 95% CI = 1.046-1.573, P = 0.017) were found associated with the severe COVID-19. For lymphocyte-related parameters, a lower level of lymphocyte count (HR = 0.571, 95% CI = 0.341-0.955, P = 0.033), and a higher CD4/CD8 ratio (HR = 2.473, 95% CI = 1.009-6.059, P = 0.048) were found related to the risk of severe COVID-19. We also observed that abnormality of red cell distribution width (RDW), mean corpuscular hemoglobin concentration (MCHC), and hemoglobin might also be involved in the development of severe COVID-19. The different trajectory patterns of RDW-SD and white blood cell count, including lymphocyte and neutrophil, prior to the infection were also discovered to have significant associations with the risk of severe COVID-19 (all P < 0.05).

CONCLUSIONS

Our findings might help decision-makers and clinicians to classify different risk groups of population due to outbreaks including COVID-19. They could not only optimize the allocation of medical resources, but also help them be more proactive instead of reactive to long COVID-19 or even other outbreaks in the future.

Thrombosis with thrombocytopenia syndrome (TTS) and vaccine-induced immune thrombocytopenia and thrombosis (VITT): Brighton Collaboration case definitions and guidelines for data collection, analysis, and presentation of immunisation safety data

This is a revision of the online November 2021 Brighton thrombosis with thrombocytopenia syndrome (TTS) case definition and a new Brighton Collaboration case definition for vaccine-induced immune thrombocytopenia and thrombosis (VITT). These case definitions are intended for use in clinical trials and post-licensure pharmacovigilance activities to facilitate safety data comparability across multiple settings. They are not intended to guide clinical management. The case definitions were developed by a group of subject matter and Brighton Collaboration process experts as part of the Coalition for Epidemic Preparedness Innovations (CEPI)-funded Safety Platform for Evaluation of vACcines (SPEAC). The case definitions, each with defined levels of diagnostic certainty, are based on relevant published evidence and expert consensus and are accompanied by specific guidelines for TTS and VITT data collection and analysis. The document underwent peer review by a reference group of vaccine safety stakeholders and haematology experts to ensure case definition useability, applicability and scientific integrity.

Recurrent Stent Thrombosis Following Myocardial Infarction Associated With VITT-Like Antibodies

Early stent thrombosis is a rare complication of percutaneous intervention and is associated with significant 30-day mortality. We present a novel case of multiple recurrent early stent thrombosis consistent with spontaneous vaccine-induced thrombotic thrombocytopenia. We were successfully able to manage this unusual condition through an interdisciplinary collaboration.

Bridging upstream and downstream for improved adenovirus 5 bioprocess

Adenoviruses are well-known viral vectors that have been previously used in gene therapy and as a vaccine-delivery vehicle for humans and animals. During the COVID-19 pandemic, it gained renewed attention, but at the same time, it raised concerns due to side effects observed with some of the resulting vaccines administered to patients. It has been indicated that these side effects might be attributed to impurities present in the final product. Therefore, constant enhancement of the vaccine purity and further improvement of impurity detection methods are needed. In this work, we showcase an example of industry-relevant adenovirus bioprocess optimization. Our data show the effect of upstream parameters on the bioburden introduced to the downstream process. We provide an example of process optimization using a combination of the PATfix analytical method, ddPCR, infectivity, total DNA, and total protein analyses to optimize cell density, multiplicity of infection, and length of production. Additionally, we provide data illustrating the robustness of the convective interaction media quaternary amine monolithic chromatography step. This anion exchange strategy was shown to remove over 99% of protein and DNA impurities, including those unable to be addressed by tangential flow filtration, while maintaining high adenovirus recoveries.

What would have happened anyway? Population data source considerations when estimating background incident rates of adverse events following immunisation to inform vaccine safety

INTRODUCTION

Understanding background incident rates of adverse events following immunisation (AEFI) is essential to rapidly detect, evaluate, respond to, and communicate about vaccine safety concerns, especially for new vaccines. Creating estimates based on geographic specific population level data is increasingly important, as new AEFI presentations will be subject to the same local influences of population demography, exposures, health system variations and level of health care sought.

METHODS

We conducted a retrospective cohort analysis of hospital admissions, emergency department presentations and general practice consultations from 2015 to 2019-before introduction of COVID-19, Mpox or Shingrix vaccination-to estimate background incident rates for 37 conditions considered potential AEFI of special interest (AESI). Background incident rates per 100,000 population were calculated and presented as cases expected to occur coincidentally 1 day, 1 week and 6 weeks post-vaccination, by life-stage age-groups and presenting healthcare setting. We then assessed the proportional contribution of each data source to inform each AESI background rate estimate.

RESULTS

16,437,156 episodes of the 37 AESI were identified. Hospital admissions predominantly informed 19 (51%) of AESI, including exclusively ADEM and CVST; 8 AESI (22%) by primary care, and 10 (27%) a mix. Four AESI (allergic urticaria, Bell's palsy, erythema multiform and sudden death) were better informed by emergency presentations than admissions, but conversely 11 AESI (30%) were not captured in ICD-10 coded emergency presentations at all.

CONCLUSIONS

Emergent safety concerns are inevitable in population-wide implementation of new vaccines, therefore understanding local background rates aids both safety signal detection as well as maintaining public confidence in vaccination. Hospital and primary care data sources can be interrogated to inform expected background incident rates of adverse events that may occur following vaccination. However, it is necessary to understand which data-source provides best intelligence according to nature of condition and presenting healthcare setting.

The first autopsy case of Epstein-Barr virus-positive marginal zone lymphoma that deteriorated after COVID-19 vaccination

This is the first autopsy case of Epstein-Barr virus-positive marginal zone lymphoma (EBV + MZL) with an other iatrogenic immunodeficiency-associated lymphoproliferative disorders (LPD) (methotrexate [MTX]-associated LPD) that deteriorated after the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. This case had a unique immunophenotype. A 71-year-old female patient with rheumatoid arthritis receiving MTX presented with fatigue 1 week after the SARS-CoV-2 vaccination. She was hospitalized due to hepatorenal dysfunction and pancytopenia. Computed tomography revealed systemic lymphadenopathy. Her physical condition deteriorated, and the patient died. The autopsy revealed systemic lymphadenopathy comprising medium-sized atypical lymphocytes and scattered Hodgkin/Reed-Sternberg (H/RS)-like cells. An immunohistochemical examination showed that atypical lymphocytes were positive for CD79a and MUM-1 and some were positive for CD20 and IRTA-1. H/RS-like cells were immunoreactive for CD30 and CD15 and ringed by T cells. Both cell types were positive for EBV-encoded small RNA. The majority of H/RS-like cells were positive for CD20, whereas a small number of CD3-positive cells were admixed. We herein presented the first autopsy case of EBV + MZL that deteriorated after the SARS-CoV-2 vaccination.

Comparison of reporting rates of arthritis and arthralgia following AstraZeneca, Pfizer-BioNTech, Moderna, and Janssen vaccine administration against SARS-CoV-2 in 2021: analysis of European pharmacovigilance large-scale data

This study aimed to investigate the reporting rates of arthritis and arthralgia following the administration of four vaccines against SARS-CoV-2: Pfizer-BioNTech (Tozinameran), Moderna (CX-024414), AstraZeneca (Chadox1 NCOV-19), and Janssen (AD26.COV2.S) in 2021. We used data from the EudraVigilance database, specifically analyzing spontaneous reports of suspected adverse reactions (ADRs) from the European Union (EU)/European Economic Area (EEA) region. Age-group-specific reporting rates were calculated by dividing the number of arthralgia and arthritis reports per 1,000,000 vaccine doses administered per age group. Reporting rates were compared using a rate ratio among the four vaccines, using the AstraZeneca vaccine as a comparator. The AstraZeneca vaccine was associated with the highest rate of arthralgia across all age groups. Arthritis reporting rates were significantly lower, with the AstraZeneca vaccine having the highest rates in most age groups, except the 60-69 and 80+ groups, where the Janssen and Pfizer-BioNTech vaccines demonstrated higher reporting rates, respectively. The distribution of arthritis rates did not follow the arthralgia pattern, being higher in the 50-79 age group. This study is the first spontaneous reporting system analysis of arthritis reporting rates post-SARS-CoV-2 vaccination at a European level, revealing a higher reporting of suspected musculoskeletal adverse reactions after AstraZeneca vaccination. The findings underscore the need to consider commonly reported events like arthralgia in risk-benefit assessments prior to vaccination against SARS-CoV-2. Given the high prevalence of rheumatic and musculoskeletal diseases and vaccine hesitancy in this population, our results could influence vaccine choice and acceptance.

COVID-19 Vaccines: Where Did We Stand at the End of 2023?

Vaccine development against SARS-CoV-2 has been highly successful in slowing down the COVID-19 pandemic. A wide spectrum of approaches including vaccines based on whole viruses, protein subunits and peptides, viral vectors, and nucleic acids has been developed in parallel. For all types of COVID-19 vaccines, good safety and efficacy have been obtained in both preclinical animal studies and in clinical trials in humans. Moreover, emergency use authorization has been granted for the major types of COVID-19 vaccines. Although high safety has been demonstrated, rare cases of severe adverse events have been detected after global mass vaccinations. Emerging SARS-CoV-2 variants possessing enhanced infectivity have affected vaccine protection efficacy requiring re-design and re-engineering of novel COVID-19 vaccine candidates. Furthermore, insight is given into preparedness against emerging SARS-CoV-2 variants.

Hematology in the post-COVID era: spotlight on vaccine-induced immune thrombotic thrombocytopenia and a conceptual framework (the 4P's) for anti-PF4 diseases

INTRODUCTION

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a life-threatening prothrombotic disorder first identified following the introduction of adenoviral vector vaccines for COVID-19. The condition is characterized by anti-PF4 antibodies and clinically presents with thrombocytopenia and thrombosis often in unusual anatomical sites.

AREAS COVERED

In this review, we discuss the clinical presentation, diagnostic testing, and treatment of VITT. We also review VITT-like syndromes that have been described in patients without previous vaccination. We propose a conceptual framework for the mechanism of anti-PF4 diseases that includes sufficiently high levels of PF4, the presence of a Polyanion that can form immune complexes with PF4, a Pro-inflammatory milieu, and an immunological Predisposition - the 4Ps.

EXPERT OPINION

Significant progress has been made in understanding the characteristics of the VITT antibody and in testing methods that can confirm that diagnosis. Future work should be directed at understanding long-term outcomes, mechanisms of thrombosis, and individual risk factors for this rare but dangerous immune-thrombotic disease.

Stroke Following Coronavirus Disease 2019 Vaccination: Evidence Based on Different Designs of Real-World Studies

BACKGROUND

We aimed to evaluate whether coronavirus disease 2019 (COVID-19) vaccination was associated with stroke.

METHODS

We conducted a systematic meta-analysis of studies using cohort, self-controlled case series (SCCS), and case-crossover study (CCOS) designs to evaluate incidence risk ratios (IRRs) and 95% confidence intervals (CIs) of ischemic stroke (IS), hemorrhagic stroke (HS), and cerebral venous sinus thrombosis (CVST) following COVID-19 vaccination. Risks of stroke were pooled among subpopulations categorized by vaccine type, dose, age, and sex. Sensitivity analysis was performed by different defined risk periods.

RESULTS

Fourteen studies involving 79 918 904 individuals were included. Cohort studies showed decreased risks of IS (IRR, 0.82 [95% CI, .75-.90]) and HS (IRR, 0.75 [95% CI, .67-.85]) postvaccination, but not CVST (IRR, 1.18 [95% CI, .70-1.98]). SCCS identified increased risks 1-21 days postvaccination (IRRIS, 1.05 [95% CI, 1.00-1.10]; IRRHS, 1.16 [95% CI, 1.06-1.26]) or 1-28 days postvaccination (IRRIS, 1.04 [95% CI, 1.00-1.08]; IRRHS, 1.37 [95% CI, 1.15-1.64]), similar to CVST (IRR, 1.58 [95% CI, 1.08-2.32]). CCOS reported an increased risk of CVST after ChAdOx1 vaccination (IRR, 2.9 [95% CI, 1.1-7.2]).

CONCLUSIONS

Although different study designs yielded inconsistent findings, considering the relatively low background incidence of stroke and benefits of vaccination, even a potentially increased risk of stroke postvaccination should not justify vaccine hesitancy.

Cerebral venous thrombosis in patients with autoimmune disease, hematonosis or coronavirus disease 2019: Many familiar faces and some strangers

BACKGROUND

Cerebral venous thrombosis, a rare stroke, is characterized by neurological dysfunction caused by bleeding and/or infarction resulting from venous sinus thrombosis, the so-called venous stroke. Current guidelines recommend anticoagulants as first-line therapy in the treatment of venous stroke. With complicated causes of cerebral venous thrombosis, treatment is difficult, especially when combined with autoimmune diseases, blood diseases, and even COVID-19.

AIMS

This review summarizes the pathophysiological mechanisms, epidemiology, diagnosis, treatment, and clinical prognosis of cerebral venous thrombosis combined with autoimmune diseases, blood diseases, or infectious diseases such as COVID-19.

CONCLUSION

A systematic understanding of particular risk factors that should not be neglected when unconventional cerebral venous thrombosis occurs and for a scientific understanding of pathophysiological mechanisms, clinical diagnosis, and treatment, thus contributing to knowledge on special types of venous stroke.

Risk of autoimmune skin and connective tissue disorders after mRNA-based COVID-19 vaccination

BACKGROUND

Data on the association between the development of autoimmune diseases and COVID-19 vaccination are limited.

OBJECTIVE

To investigate the incidence and risk of autoimmune connective tissue disorders following mRNA-based COVID-19 vaccination.

METHODS

This nationwide population-based study was conducted in South Korea. Individuals who received vaccination between September 8, 2020-December 31, 2021, were identified. Historical prepandemic controls were matched for age and sex in 1:1 ratio. The incidence rate and risk of disease outcomes were compared.

RESULTS

A total of 3,838,120 vaccinated individuals and 3,834,804 controls without evidence of COVID-19 were included. The risk of alopecia areata, alopecia totalis, primary cicatricial alopecia, psoriasis, vitiligo, anti-neutrophil cytoplasmic antibody-associated vasculitis, sarcoidosis, Behcet disease, Crohn disease, ulcerative colitis, rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, Sjogren syndrome, ankylosing spondylitis, dermato/polymyositis, and bullous pemphigoid was not significantly higher in vaccinated individuals than in controls. The risk was comparable according to age, sex, type of mRNA-based vaccine, and cross-vaccination status.

LIMITATIONS

Possible selection bias and residual confounders.

CONCLUSION

These findings suggest that most autoimmune connective tissue disorders are not associated with a significant increase in risk. However, caution is necessary when interpreting results for rare outcomes due to limited statistical power.

Heterologous vaccination (ChAdOx1 and BNT162b2) induces a better immune response against the omicron variant than homologous vaccination

BACKGROUND

The ongoing COVID-19 pandemic has seen the emergence of numerous novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. In this study, we compared the efficacy of three different forms of immunization against the wild-type, delta, and omicron variants of the virus: two doses of the BNT or AZ vaccine (BNT/BNT or AZ/AZ) as homologous vaccination, three doses of AZ/AZ/BNT as heterologous vaccination, and naturally occurring immunization in severe COVID-19 cases.

METHODS

We collected serum samples from vaccine recipients (67 receiving BNT/BNT, 111 receiving AZ/AZ, and 18 receiving AZ/AZ/BNT) and 46 patients who were admitted to the hospital with severe COVID-19. Blood samples were taken one month after the last injection and the efficacy of the vaccination was determined using the surrogate virus neutralization test (sVNT), with a positive result defined as an inhibition rate of over 30%. Serum samples from COVID-19 patients were taken at various points during their hospitalization and tested for inhibition rates.

RESULTS

Our results indicated that there was no notable difference in the levels of neutralizing antibodies (nAb) in vaccine recipients and patients against the wild-type and delta variants. However, when it came to the omicron variant, the vaccine recipients had significantly lower nAb titers. Among the vaccine recipients, those who received a booster dose of BNT after their first two doses of AZ (AZ/AZ/BNT) demonstrated the highest level of protection against the omicron variant at 44.4%, followed closely by the COVID-19 patients. In analyzing the serial samples taken from hospitalized COVID-19 patients, we observed that their inhibition rates against the wild-type and delta variants improved over time, while the inhibition rate against the omicron variant decreased.

CONCLUSION

In conclusion, our findings suggest that heterologous booster vaccination after primary vaccination produces higher nAb titers and provides a higher level of protection against the omicron variant compared to primary vaccination alone. This protective effect was similar to that observed in patients with severe COVID-19.

PAD4-Induced NETosis Via Cathepsin G-Mediated Platelet-Neutrophil Interaction in ChAdOx1 Vaccine-Induced Thrombosis-Brief Report

BACKGROUND

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare syndrome characterized by platelet anti-PF4 (platelet-activating antiplatelet factor 4)-related thrombosis. Platelet-neutrophil interaction has been suggested to play a role, but the underlying mechanism has not been fully elucidated.

METHODS

The study included 10 patients with VITT after ChAdOx1 (chimpanzee adenovirus Oxford 1) nCoV-19 (Oxford-AstraZeneca) vaccine administration, 10 patients with ischemic stroke (IS), 10 patients with acute deep vein thrombosis, and 10 control subjects in whom blood levels of neutrophil extracellular traps (NETs), soluble TF (tissue factor), and thrombin generation were examined. Furthermore, we performed in vitro studies comparing the effect of serum from patients and controls on NETs formation. Finally, immunohistochemistry was performed in cerebral thrombi retrieved from a patients with VITT and 3 patients with IS.

RESULTS

Compared with patients with IS, patients with deep vein thrombosis, controls, and patients with VITT had significantly higher blood values of CitH3 (citrullinated histone H3), soluble TF, D-dimer, and prothrombin fragment 1+2 (P<0.0001). Blood CitH3 significantly correlated with blood soluble TF (Spearman rank correlation coefficient=0.7295; P=0.0206) and prothrombin fragment 1+2 (Spearman rank correlation coefficient=0.6809; P<0.0350) in patients with VITT. Platelet-neutrophil mixture added with VITT plasma resulted in higher NETs formation, soluble TF and thrombin generation, and platelet-dependent thrombus growth under laminar flow compared with IS and deep vein thrombosis plasma; these effects were blunted by PAD4 (protein arginine deiminase 4) and cathepsin G inhibitors, anti-FcγRIIa (Fc receptor for IgG class IIa), and high doses of heparin. Immunohistochemistry analysis showed a more marked expression of PAD4 along with more diffuse neutrophil infiltration and NETs formation as well as TF and cathepsin expression in VITT thrombus compared with thrombi from patients with IS.

CONCLUSIONS

Patients with VITT display enhanced thrombogenesis by PAD4-mediated NETs formation via cathepsin G-mediated platelet/neutrophil interaction.

Different Safety Pattern of an Inactivated SARS-CoV-2 Vaccine (CoronaVac®) According to Age Group in a Pediatric Population from 3 to 17 Years Old, in an Open-Label Study in Chile

During the COVID-19 pandemic, the importance of vaccinating children against SARS-CoV-2 was rapidly established. This study describes the safety of CoronaVac® in children and adolescents between 3- and 17-years-old in a multicenter study in Chile with two vaccine doses in a 4-week interval. For all participants, immediate adverse events (AEs), serious AEs (SAEs), and AEs of special interest (AESIs) were registered throughout the study. In the safety subgroup, AEs were recorded 28 days after each dose. COVID-19 surveillance was performed throughout the study. A total of 1139 individuals received the first and 1102 the second dose of CoronaVac®; 835 were in the safety subgroup. The first dose showed the highest number of AEs: up to 22.2% of participants reported any local and 17.1% systemic AE. AEs were more frequent in adolescents after the first dose, were transient, and mainly mild. Pain at the inoculation site was the most frequent AE for all ages. Fever was the most frequent systemic AE for 3-5 years old and headache in 6-17 years old. No SAEs or AESIs related to vaccination occurred. Most of the COVID-19 cases were mild and managed as outpatients. CoronaVac® was safe and well tolerated in children and adolescents, with different safety patterns according to age.

COVID-19 vaccines and their underbelly: Are we going the right way?

Background

Historically, a critical aetiological agent of health concern stays till eternity after its discovery, so shall it be with the COVID-19 outbreak. It has transformed human life to a 'new normal' with huge tolls on the social, psychological, intellectual and financial spheres.

Aim

This perspective aimed to collate numerous reported COVID-19 vaccine-associated adverse events and the predisposing factors. It focussed on the efficacy of mix-n-match (cocktail) vaccines to effectively counter COVID-19 infection to facilitate future research and possible interventions.

Material and Methods

Databases like Scopus, Pubmed and the Web-of-science were searched for published literature on 'adverse events associated with COVID-19 vaccine'. The reports and updates from health agencies like the WHO and CDC were also considered for the purpose. The details with respect to the adverse events associated with COVID-19 vaccination and the predisposing factors were compiled to obtain insights and suggest possible future directions in vaccine research.

Results

India stood strong to manage its health resources in time and turned into a dominant global vaccine supplier at a time when healthcare infrastructure of many countries was still significantly challenged. Developing indigenous vaccines and the vaccination drive in India were its major achievements during the second and the subsequent COVID-19 waves. The fully indigenous Covaxin vaccine, primarily as an emergency intervention, was successfully rapidly launched. Similar such vaccines for emergency use were developed elsewhere as well. However, all of these reached the marketplace with a 'emergency use only' tag, without formal clinical trials and other associated formalities to validate and verify them as these would require much longer incubation time before they are available for human use.

Discussion

Many adverse events associated with either the first or the second/booster vaccination doses were reported. Evidently, these associated adverse events were considered as 'usually rare' or were often underreported. Without the additional financial or ethical burden on the vaccine companies, fortunately, the Phase IV (human) clinical trials of their manufactured vaccines are occurring by default as the human population receives these under the tag 'emergency use'. Thus, focused and collaborative strategies to unveil the molecular mechanisms in vaccine-related adverse events in a time-bound manner are suggested.

Conclusion

Reliable data particularly on the safety of children is lacking as majority of the current over-the-counter COVID-19 vaccines were for emergency use. Many of these were still in their Phase III and Phase IV trials. The need for a mutant-proof, next-gen COVID-19 vaccine in the face of vaccine-associated adverse events is opined.

Mucosal Application of a Low-Energy Electron Inactivated Respiratory Syncytial Virus Vaccine Shows Protective Efficacy in an Animal Model

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infections in the elderly and in children, associated with pediatric hospitalizations. Recently, first vaccines have been approved for people over 60 years of age applied by intramuscular injection. However, a vaccination route via mucosal application holds great potential in the protection against respiratory pathogens like RSV. Mucosal vaccines induce local immune responses, resulting in a fast and efficient elimination of respiratory viruses after natural infection. Therefore, a low-energy electron irradiated RSV (LEEI-RSV) formulated with phosphatidylcholine-liposomes (PC-LEEI-RSV) was tested ex vivo in precision cut lung slices (PCLSs) for adverse effects. The immunogenicity and protective efficacy in vivo were analyzed in an RSV challenge model after intranasal vaccination using a homologous prime-boost immunization regimen. No side effects of PC-LEEI-RSV in PCLS and an efficient antibody induction in vivo could be observed. In contrast to unformulated LEEI-RSV, the mucosal vaccination of mice with PC formulated LEEI-RSV showed a statistically significant reduction in viral load after challenge. These results are a proof-of-principle for the use of LEEI-inactivated viruses formulated with liposomes to be administered intranasally to induce a mucosal immunity that could also be adapted for other respiratory viruses.

Eosinophilic Granulomatosis with Polyangiitis after mRNA-1273 SARS-CoV-2 Vaccine

During one of the worst global health crises, millions of people were vaccinated against SARS-CoV-2. In rare cases, new onset systemic inflammatory diseases were reported with temporal coincidence to the vaccination. We describe a case of severe Eosinophilic Granulomatosis with Polyangiitis (EGPA) in a young asthmatic woman, occurring after a second dose of the mRNA-1273 vaccine. She presented with multisystem EGPA with cardiac and central nervous system involvement, complicated by secondary immune thrombocytopenia (ITP). We review the reported cases of EGPA coinciding with SARS-CoV-2 mRNA vaccination. All potentially vaccine-related EGPA cases reported so far occurred within 14 days from immunization. EGPA is very rare with an incidence of 1:1,000,000 inhabitants, and the number of reported post-vaccination EGPA cases lies within the expected incidence rate for the period. While we cannot prove a causal relationship between the vaccine and EGPA onset, the temporal relationship with the vaccine immune stimulation is intriguing, in a disease occurring almost always in adults with asthma and/or chronic rhinosinusitis and driven by an aberrant Th2 lymphocyte activation with hypereosinophilia; nevertheless, cases of inflammatory diseases (IMIDs) emerging in the context of vaccination remain rare and the benefits of preventing severe COVID presentations with SARS-CoV-2 mRNA vaccines remain unquestionable.

Association of inactivated COVID-19 vaccination with maternal coagulation function in early pregnancy

Reports of rare but severe thrombotic events after receiving some COVID-19 vaccines brought concerns for the possibility of vaccine-induced coagulation abnormality. However, no study has reported the impacts of COVID-19 vaccination on coagulation function in pregnant women. We aimed to explore whether vaccination with inactivated COVID-19 vaccines before pregnancy was associated with coagulation changes in pregnant women. We conducted a retrospective cohort study in a tertiary-care hospital in Shanghai, China. A total of 5166 pregnant women were included, of whom 2721 (52.7%) completed vaccination before conception. Compared with unvaccinated women, the mean serum levels of prothrombin time (PT) and fibrinogen (FIB) were lower in vaccinated women by 0.09 (β = -0.09, 95% confidence interval [CI], -0.13, -0.05) mg/L and 0.11 (β = -0.11, 95% CI, -0.15, -0.07) mg/L, and the mean D-Dimer (D-D) levels were higher by 0.12 (β = 0.12, 95% CI, 0.09, 0.15) mg/L. However, no significant association was observed between COVID-19 vaccination and serum levels of activated partial thromboplastin time (APTT), fibrinogen degradation product (FDP) or thrombin time (TT). Our findings suggested that inactivated COVID-19 vaccination before conception resulted in a small change in maternal coagulation function, but this might not have clinical significance.

Menstrual disturbances following COVID-19 vaccination: A probable puzzle about the role of endocrine and immune pathways

Menstruation is a monthly shedding of the uterine wall, presented by menstrual bleeding in women of reproductive age. Menstruation is regulated by fluctuation of estrogen and progesterone, as well as other endocrine and immune pathways. Many women experienced menstrual disturbances after vaccination against the novel coronavirus in the last two years. Vaccine-induced menstrual disturbances have led to discomfort and concern among reproductive-age women, such that some decided not to receive the subsequent doses of the vaccine. Although many vaccinated women report these menstrual disturbances, the mechanism is still poorly understood. This review article discusses the endocrine and immune changes following COVID-19 vaccination and the possible mechanisms of vaccine-related menstrual disturbances.

Retinal Vein Occlusion after COVID-19 Vaccination-A Review

Background Retinal vein occlusion (RVO) occurring after COVID-19 vaccination has been reported worldwide. Such a sight-threatening condition occurring after COVID-19 vaccination is a menace to ophthalmic health. This article reviews current evidence related to post-COVID-19 vaccination RVO. Method A total of 29 relevant articles identified on PubMed in January 2023 were selected for review. Observation All cases presented to ophthalmologists with visual loss shortly after COVID-19 vaccination. Mean and median age were both 58. No sex predominance was observed. RVO was diagnosed from findings on dilated fundal examination and ophthalmic imaging. AstraZeneca and BNT vaccines accounted for most cases. Vascular risk factors, e.g., diabetes mellitus and hypertension, were common. Most laboratory tests requested came back unremarkable. Most patients responded well to standard treatment, except those with ophthalmic comorbidities. Visual prognosis was excellent on short-term follow-up. Discussion The causality between RVO and COVID-19 vaccination is undeterminable because of the nature of articles, heterogenous reporting styles, contradicting laboratory findings and co-existing vascular risk factors. Vaccine-induced immune thrombotic thrombocytopenia, retinal vasculitis and homocysteinaemia were proposed to explain post-vaccination RVO. Large-scale studies have demonstrated that the incidence of RVO following COVID vaccination is very low. Nevertheless, the effects of boosters on retinal vasculature and ophthalmic health are still unclear. Conclusions The benefits of COVID-19 vaccination are believed to outweigh its ophthalmic risks. To ensure safe vaccination, the prior optimisation of comorbidities and post-vaccination monitoring are important. COVID-19 vaccines (including boosters) should be offered with reasonable confidence. Further studies are warranted to elucidate the ophthalmic impact of vaccines.

New Onset Autoimmune Diseases after the Sputnik Vaccine

The vertiginous advance for identifying the genomic sequence of SARS-CoV-2 allowed the development of a vaccine including mRNA-based vaccines, inactivated viruses, protein subunits, and adenoviral vaccines such as Sputnik. This study aims to report on autoimmune disease manifestations that occurred following COVID-19 Sputnik vaccination. Patients and Methods: A retrospective study was conducted on patients with new-onset autoimmune diseases induced by a post-COVID-19 vaccine between March 2021 and December 2022, in two referral hospitals in Mexico City and Argentina. The study evaluated patients who received the Sputnik vaccine and developed recent-onset autoimmune diseases. Results: Twenty-eight patients developed recent-onset autoimmune diseases after Sputnik vaccine. The median age was 56.9 ± 21.7 years, with 14 females and 14 males. The autoimmune diseases observed were neurological in 13 patients (46%), hematological autoimmune manifestations occurred in 12 patients (42%), with thrombotic disease observed in 10 patients (28%), and autoimmune hemolytic anemia in two patients (7.1%). Rheumatological disorders were present in two patients (7.1%), and endocrine disorders in one patient (3.5%). Principio del formulario Conclusion: Although the COVID-19 Sputnik vaccine is generally safe, it can lead to adverse effects. Thrombosis and Guillain-Barre were the most frequent manifestations observed in our group of patients.

How to approach acute thrombosis and thrombocytopenia

Acute thrombosis and thrombocytopenia pose challenges to the clinician. Thrombocytopenia is naturally viewed as a risk factor for bleeding, and an association with acute thrombosis appears paradoxical. It presents typically as a medical emergency and requires treatment to be started before having confirmatory results. This review supports the attending clinician to recognise and manage conditions that are part of the thrombotic thrombocytopenic syndrome through four illustrative clinical cases. Common themes linking the underlying pathology and treatment are explored to highlight the continued relevance of this rare, but often devastating, presentation.

Hematologic adverse events reported after COVID-19 vaccination in the Philippines: A national database study

Vaccination is the most important strategy in preventing COVID-19. Vaccine efficacy and safety have been established in clinical trials but real-world data are useful to determine occurrence of adverse events in a population with heterogeneous characteristics. Knowledge on the hematologic events associated with different COVID-19 vaccines would be beneficial for patients as well as hematologists who oversee the care of these patients. This study aimed to determine the rates and outcomes of hematologic adverse events after COVID-19 vaccination in the Philippines. In this self-controlled case series, there were 268 individuals reported to have hematologic adverse events. Most received Comirnaty at 29.85%. Majority (62.31%) reported hematologic adverse events following the first dose of the vaccine. The overall event rate was 0.0182 per 10,000 vaccine doses; and lymphadenopathy was the most common hematologic adverse effect with a rate of 0.011 per 10,000 vaccine doses, followed by anemia at 0.0034 per 10,000 vaccine doses and thrombocytopenia at 0.0017 per 10,000 vaccine doses. Autoimmune cytopenias were also reported with an event rate of 0.0007 per 10,000 vaccine doses for ITP. One-hundred thirty two (49.25%) were fully recovered and 23.88% were recovering from hematologic adverse events as of the time of writing. The study showed a low rate of hematologic adverse events post COVID-19 vaccination with the seven different vaccine brands administered in the Philippines.

Intranasal administration of adenoviral vaccines expressing SARS-CoV-2 spike protein improves vaccine immunity in mouse models

The ongoing SARS-CoV-2 pandemic is controlled but not halted by public health measures and mass vaccination strategies which have exclusively relied on intramuscular vaccines. Intranasal vaccines can prime or recruit to the respiratory epithelium mucosal immune cells capable of preventing infection. Here we report a comprehensive series of studies on this concept using various mouse models, including HLA class II-humanized transgenic strains. We found that a single intranasal (i.n.) dose of serotype-5 adenoviral vectors expressing either the receptor binding domain (Ad5-RBD) or the complete ectodomain (Ad5-S) of the SARS-CoV-2 spike protein was effective in inducing i) serum and bronchoalveolar lavage (BAL) anti-spike IgA and IgG, ii) robust SARS-CoV-2-neutralizing activity in the serum and BAL, iii) rigorous spike-directed T helper 1 cell/cytotoxic T cell immunity, and iv) protection of mice from a challenge with the SARS-CoV-2 beta variant. Intramuscular (i.m.) Ad5-RBD or Ad5-S administration did not induce serum or BAL IgA, and resulted in lower neutralizing titers in the serum. Moreover, prior immunity induced by an intramuscular mRNA vaccine could be potently enhanced and modulated towards a mucosal IgA response by an i.n. Ad5-S booster. Notably, Ad5 DNA was found in the liver or spleen after i.m. but not i.n. administration, indicating a lack of systemic spread of the vaccine vector, which has been associated with a risk of thrombotic thrombocytopenia. Unlike in otherwise genetically identical HLA-DQ6 mice, in HLA-DQ8 mice Ad5-RBD vaccine was inferior to Ad5-S, suggesting that the RBD fragment does not contain a sufficient collection of helper-T cell epitopes to constitute an optimal vaccine antigen. Our data add to previous promising preclinical results on intranasal SARS-CoV-2 vaccination and support the potential of this approach to elicit mucosal immunity for preventing transmission of SARS-CoV-2.

Approach to the Patient With Adrenal Hemorrhage

Adrenal hemorrhage is an uncommon, underrecognized condition that can be encountered in several clinical contexts. Diagnosing adrenal hemorrhage is challenging due to its nonspecific clinical features. Therefore, it remains a diagnosis that is made serendipitously on imaging of acutely unwell patients rather than with prospective clinical suspicion. Adrenal hemorrhage can follow abdominal trauma or appear on a background of predisposing conditions such as adrenal tumors, sepsis, or coagulopathy. Adrenal hemorrhage is also increasingly reported in patients with COVID-19 infection and in the context of vaccine-induced immune thrombocytopenia and thrombosis. Unexplained abdominal pain with hemodynamic instability in a patient with a predisposing condition should alert the physician to the possibility of adrenal hemorrhage. Bilateral adrenal hemorrhage can lead to adrenal insufficiency and potentially fatal adrenal crisis without timely recognition and treatment. In this article, we highlight the clinical circumstances that are associated with higher risk of adrenal hemorrhage, encouraging clinicians to prospectively consider the diagnosis, and we share a diagnostic and management strategy.

Platelet, a key regulator of innate and adaptive immunity

Platelets, anucleate blood components, represent the major cell type involved in the regulation of hemostasis and thrombosis. In addition to performing haemostatic roles, platelets can influence both innate and adaptive immune responses. In this review, we summarize the development of platelets and their functions in hemostasis. We also discuss the interactions between platelet products and innate or adaptive immune cells, including neutrophils, monocytes, macrophages, T cells, B cells and dendritic cells. Activated platelets and released molecules regulate the differentiation and function of these cells via platelet-derived receptors or secreting molecules. Platelets have dual effects on nearly all immune cells. Understanding the exact mechanisms underlying these effects will enable further application of platelet transfusion.

Head-to-head comparison of four COVID-19 vaccines on platelet activation, coagulation and inflammation. The TREASURE study

INTRODUCTION

Studies exploring alterations in blood coagulation and platelet activation induced by COVID-19 vaccines are not concordant. We aimed to assess the impact of four COVID-19 vaccines on platelet activation, coagulation, and inflammation considering also the immunization dose and the history of SARS-CoV-2 infection.

METHODS

TREASURE study enrolled 368 consecutive subjects (161 receiving viral vector vaccines -ChAdOx1-S/Vaxzevria or Janssen- and 207 receiving mRNA vaccines -Comirnaty/Pfizer-BioNTech or Spikevax/Moderna). Blood was collected the day before and 8 ± 2 days after the vaccination. Platelet activation markers (P-selectin, aGPIIbIIIa and Tissue Factor expression; number of platelet-monocyte and -granulocyte aggregates) and microvesicle release were analyzed by flow cytometry. Platelet thrombin generation (TG) capacity was measured using the Calibrated Automated Thrombogram. Plasma coagulation and inflammation markers and immune response were evaluated by ELISA.

RESULTS

Vaccination did not induce platelet activation and microvesicle release. IL-6 and CRP levels (+30%), D-dimer, fibrinogen and F₁₊₂ (+13%, +3.7%, +4.3%, respectively) but not TAT levels significantly increased upon immunization with all four vaccines, with no difference among them and between first and second dose. An overall minor post-vaccination reduction of aPC, TM and TFPI, all possibly related to endothelial function, was observed. No anti-PF4 seroconversion was observed.

CONCLUSION

This study showed that the four COVID-19 vaccines administered to a large population sample induce a transient inflammatory response, with no onset of platelet activation. The minor changes in clotting activation and endothelial function might be potentially involved at a population level in explaining the very rare venous thromboembolic complications of COVID-19 vaccination.

Incidence of sinus thrombosis with thrombocytopenia-A nation-wide register study

Safe vaccination is essential for mitigation of the COVID-19 pandemic. Two adenoviral vector vaccines, ChAdOx1 nCov-19 (AstraZeneca) and Ad26.COV2.S (Johnson&Johnson/Janssen) have shown to be effective and they are distributed globally, but reports on serious cerebral venous sinus thrombosis (CVST) associated with thrombocytopenia, have emerged. Our objective was to evaluate the background incidence of CVST with thrombocytopenia and to compare it to incidences following COVID-19 vaccines. We conducted a register-based nation-wide cohort study in Finland, including all 5.5 million individuals alive in Finland, 1 Jan 2020. COVID-19 vaccinations registered in the National Vaccination Register served as the exposure. We detected CVST admissions or hospital visits recorded in the hospital discharge register from Jan 1, 2020 through April 2, 2021. We confirmed the diagnosis of CVST and thrombocytopenia (platelet count <150,000 per cubic millimeter) using radiology reports and laboratory data. By Poisson regression, we compared the baseline incidences to the risks within four weeks after COVID-19 vaccinations. Out of the 167 CVST episodes identified in the registers, 117 were confirmed as CVST, 18 of which coincided with thrombocytopenia (baseline incidence 0.18 per 28 days per million persons). We found 2 episodes of CVST with thrombocytopenia within 28 days of the first ChAdOx1 nCov-19 vaccination (among 200,397 vaccinated, aged 16 or above). No cases were found following the first mRNA vaccine dose among 782,604 vaccinated. The background incidence of CVST combined with thrombocytopenia was minuscule compared to the incidence during the weeks following the ChAdOx1 nCov-19 vaccination. Accurate estimation of the baseline incidence is essential in the critical appraisal of the benefit-risk of any vaccination program.

COVID-19 Vaccine-Associated Immune Thrombosis and Thrombocytopenia (VITT): Diagnostic Discrepancies and Global Implications

Vaccine-induced immune thrombotic thrombocytopenia (VITT) has been reported in association with the coronavirus disease 2019 preventative adenovirus vector-based vaccines ChAdOx1 nCoV-19 (Oxford/AstraZeneca) and Ad26.COV2.S (Janssen/Johnson & Johnson) in hundreds of recipients across the globe. VITT is characterized by thrombosis, typically at unusual sites, low fibrinogen, and elevated plasma D-dimer, generally manifesting between 4 and 28 days following vaccination. Detection of anti-platelet factor antibodies using an enzyme-linked immunosorbent assay (ELISA) is often confirmatory. Although several similar principles subside in most diagnostic criteria for VITT, the presentation of a positive ELISA assay, use of expert hematology and neurology opinion, and exclusion of possible VITT cases outside the "standard" 4 to 28-day timeframe have contributed a lack of global standardization for defining VITT. Accordingly, the global and regional incidence of VITT differs according to the diagnostic pathway and case definition used. This has influenced the public perception of VITT's severity and the decision to use adenovirus vector-based vaccines for limiting severe acute respiratory syndrome coronavirus 2 infection. We hereby delineate the recognized pathogenic mechanisms, global incidence, discrepancies in diagnostic criteria, recommended treatments, and global implications to vaccine hesitancy from this coagulopathy.

SARS-CoV-2 Vaccination-Induced Thrombotic Thrombocytopenia: A Rare but Serious Immunologic Complication

Billions of individuals worldwide have benefited from the unprecedented large-scale rollout of COVID-19 vaccines. Given the sheer number of people that have received these vaccines, it is not surprising that rare side effects are reported that were not previously detected in the phase III vaccine trials. This review addresses one rare complication called SARS-CoV-2 vaccination-induced thrombotic thrombocytopenia (VITT). It occurs in approximately 1/50,000 to 1/100,000 recipients of the adenovirus vector-based COVID-19 vaccines made by AstraZeneca-Oxford or Johnson & Johnson. Information on VITT syndrome was disseminated quickly via social media and publications after it was first discovered. Initial observations associating VITT with specific patient populations, thrombus locations, and outcomes associated with heparin therapy have since been refined with additional clinical experience. In this review, we discuss what is currently known about the incidence, pathophysiology, diagnosis, and treatment of VITT.

Prevention and Treatment Strategies for Respiratory Syncytial Virus (RSV)

Respiratory syncytial virus (RSV) is a leading cause of severe lower respiratory tract disease, especially in young children. Despite its global impact on healthcare, related to its high prevalence and its association with significant morbidity, the current therapy is still mostly supportive. Moreover, while more than 50 years have passed since the first trial of an RSV vaccine (which unfortunately caused enhanced RSV disease), no vaccine has been approved for RSV prevention. In the last two decades, our understanding of the pathogenesis and immunopathology of RSV have continued to evolve, leading to significant advancements in RSV prevention strategies. These include both the development of new potential vaccines and the successful implementation of passive immunization, which, together, will provide coverage from infancy to old age. In this review, we provide an update of the current treatment options for acute disease (RSV-specific and -non-specific) and different therapeutic approaches focusing on RSV prevention.

Reactogenicity of various COVID-19 vaccination regimens

During the spread of an increasing number of new variants of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2), it is extremely important not only to assess the immunogenicity and efficacy, butalso the safety of various combinations of vaccines. Excessive immune response and associated signs and symptoms may occur with varying frequency as expected from the use of vaccines.

Aim. To compare the reactogenicity of various (heterologous and homologous) vaccination regimens in a prospective observational study.

Material and methods. In individuals aged ≥18 years, in the absence of contraindications to vaccination, two types of vaccines were used at primary vaccination and revaccination: Gam-COVID-Vac and CoviVac: group I (n=97) — Gam-COVID-Vac at each stage of primary and booster vaccination ; group II (n=7) — Gam-COVID-Vck at each stage of primary vaccination, CoviVac at each stage of revaccination; group III (n=42) — CoviVac at each stage of primary vaccination, Gam-COVID-Vac at each stage of revaccination; group IV (n=38) — CoviVac at each stage of primary and secondary vaccination. In all participants, the dynamics of IgG to SARS-CoV-2 spike glycoprotein receptor-binding domain and T-cell immunity to SARS-CoV-2 were determined over time. To control the plasma hemostasis, the method of dynamic thrombophotometry was used. Local and systemic adverse events were assessed.

Results. The number of vaccinated individuals with a rise in body temperature above 370 C after the 1st stage of revaccination was significantly (p<0,05) more in group I (37,5%) and group II (57,1%) compared with vaccinated persons of IV group. At the same time, after the 2nd stage of revaccination, in general, a smaller percentage of vaccinated persons with hyperthermia was noted. In group I, a higher percentage of persons (22,9%) complaining of the appearance of weakness after stage I of revaccination was noted compared to vaccinated persons of group IV — 5,2%. An increase in the fibrin clot growth rate was noted in group III at the stage of revaccination.

Conclusion. The use of various revaccination schemes (homologous and heterologous) was not associated with the development of serious adverse events. The resulting local and systemic reactions were shortlived and did not require hospitalization. More pronounced systemic reactions were noted in the form of a short-term fever and weakness when using the Gam-COVID-Vac. No cases of arterial or venous thrombosis were registered during the follow-up period.

Acute macular neuroretinopathy and COVID-19 vaccination: Case report and literature review

OBJECTIVE

To review cases of acute macular neuroretinopathy (AMN) after COVID-19 vaccination and add a similar case to the literature.

METHODS

A thorough PubMed search was conducted, and data from studies describing AMN after COVID-19 vaccination were extracted, tabulated, pooled, and reviewed.

RESULTS

We present a case of AMN in a young woman 5 days after immunization with the BBIBP-CorV (Sinopharm) COVID-19 vaccine. Data from 21 cases were pooled and reviewed. The most frequent vaccines among the cases were recombinant ones (13/21), followed by mRNA-based (6/21) and inactivated vaccines (2/21). Only one patient (5%) was male. Seventeen over twenty-one (81%) were young women, ages 18-33. Most cases (14/21; 67%) reported recent/concurrent use of contraceptive medication. In 90% of cases (19/21), symptoms appeared within 8 days of vaccination. A confined wedge-/oval-shaped lesion morphology was more frequent than a diffuse, semilunar one. Resolution of symptoms took 4 to over 15 weeks.

CONCLUSION

Attention should be paid to the history of vaccination and contraceptive use in patients with sudden-onset visual symptoms. Optical coherence tomography is integral to the detection of AMN-related abnormalities.

New perspectives on the induction and acceleration of immune-associated thrombosis by PF4 and VWF

Platelet factor 4 (PF4), also known as chemokine (C-X-C motif) ligand 4 (CXCL4), is a specific protein synthesized from platelet α particles. The combination of PF4 and heparin to form antigenic complexes is an important mechanism in the pathogenesis of heparin-induced thrombocytopenia (HIT), but vaccine-induced immune thrombotic thrombocytopenia (VITT) related to the COVID-19 vaccine makes PF4 a research hotspot again. Similar to HIT, vaccines, bacteria, and other non-heparin exposure, PF4 can interact with negatively charged polyanions to form immune complexes and participate in thrombosis. These anions include cell surface mucopolysaccharides, platelet polyphosphates, DNA from endothelial cells, or von Willebrand factor (VWF). Among them, PF4-VWF, as a new immune complex, may induce and promote the formation of immune-associated thrombosis and is expected to become a new target and therapeutic direction. For both HIT and VITT, there is no effective and targeted treatment except discontinuation of suspected drugs. The research and development of targeted drugs based on the mechanism of action have become an unmet clinical need. Here, this study systematically reviewed the characteristics and pathophysiological mechanisms of PF4 and VWF, elaborated the potential mechanism of action of PF4-VWF complex in immune-associated thrombosis, summarized the current status of new drug research and development for PF4 and VWF, and discussed the possibility of this complex as a potential biomarker for early immune-associated thrombosis events. Moreover, the key points of basic research and clinical evaluation are put forward in the study.

COVID-19 Vaccination in Korea

Since December 2020, various coronavirus disease 2019 (COVID-19) vaccines have been developed and approved. As of February 2023, mRNA vaccines including bivalent vaccines (Pfizer/BioNTech, Moderna), recombinant protein vaccines (Novavax, SK Bioscience), and viral vector vaccines (AstraZeneca, Janssen) have been approved in Korea. COVID-19 vaccination can effectively reduce hospitalization and deaths due to symptomatic COVID-19, especially severe and critical COVID-19. The primary series vaccination against COVID-19 is recommended for all adults aged ≥18 years in Korea. Booster vaccination with the bivalent mRNA vaccine is available for those ≥12 years who have completed the primary series vaccination, regardless of the type of vaccine previously received, and is recommended for all adults. Booster vaccination can be administered since 90 days after the last dose. Localized and systemic adverse events following COVID-19 vaccination are relatively common and more frequently documented in younger age groups. Rare but potentially serious specialized adverse reactions include anaphylaxis, thrombosis with thrombocytopenia syndrome, myocarditis, and Guillain-Barré syndrome. Previous severe allergic reactions, such as anaphylaxis, to any COVID19 vaccine or vaccine component are considered a contraindication for vaccination. The indications and schedule for COVID-19 vaccination are subject to change based on further research results and the COVID-19 pandemic.

Respiratory syncytial virus prevention within reach: the vaccine and monoclonal antibody landscape

Respiratory syncytial virus is the second most common cause of infant mortality and a major cause of morbidity and mortality in older adults (aged >60 years). Efforts to develop a respiratory syncytial virus vaccine or immunoprophylaxis remain highly active. 33 respiratory syncytial virus prevention candidates are in clinical development using six different approaches: recombinant vector, subunit, particle-based, live attenuated, chimeric, and nucleic acid vaccines; and monoclonal antibodies. Nine candidates are in phase 3 clinical trials. Understanding the epitopes targeted by highly neutralising antibodies has resulted in a shift from empirical to rational and structure-based vaccine and monoclonal antibody design. An extended half-life monoclonal antibody for all infants is likely to be within 1 year of regulatory approval (from August, 2022) for high-income countries. Live-attenuated vaccines are in development for older infants (aged >6 months). Subunit vaccines are in late-stage trials for pregnant women to protect infants, whereas vector, subunit, and nucleic acid approaches are being developed for older adults. Urgent next steps include ensuring access and affordability of a respiratory syncytial virus vaccine globally. This review gives an overview of respiratory syncytial virus vaccines and monoclonal antibodies in clinical development highlighting different target populations, antigens, and trial results.

Recommendations on the Management of Patients with Immune Thrombocytopenia (ITP) in the Context of SARS-CoV-2 Infection and Vaccination: Consensus Guidelines from a Spanish ITP Expert Group

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease with highly variable presentation, characteristics, and clinical course. Thrombocytopenia is a common complication of many viral infections, including SARS-CoV-2. In addition, both de novo ITP and exacerbation of ITP after vaccination against SARS-CoV-2 have been reported. Patients infected with SARS-CoV-2 develop a prothrombotic coagulopathy called COVID-19-associated coagulopathy (CAC). In addition, autoimmune hematological disorders secondary to SARS-CoV-2 infection, mainly ITP and autoimmune hemolytic anemia (AIHA), have been described. Furthermore, SARS-CoV-2 infection has been associated with exacerbation of autoimmune processes, including ITP. In fact, there is evidence of a high relapse rate in patients with preexisting ITP and COVID-19. As for vaccination against SARS-CoV-2, hematological adverse events (HAE) are practically anecdotal. The most common HAE is thrombocytopenia-associated thrombosis syndrome (TTS) linked to vectored virus vaccines. Other HAEs are very rare, but should be considered in patients with previous complement activation disease or autoimmunity. In patients with ITP who are vaccinated against SARS-CoV-2, the main complication is exacerbation of ITP and the bleeding that may result. In fact, this complication occurs in 12% of patients, with splenectomized and refractory patients with more than five lines of previous treatment and platelet counts below 50 × 10⁹/L being the most vulnerable. We conclude that, in general, there is no greater risk of severe SARS-CoV-2 infection in ITP patients than in the general population. Furthermore, no changes are advised in patients with stable ITP, the use of immunosuppressants is discouraged unless there is no other therapeutic option, and patients with ITP are not contraindicated for vaccination against COVID-19.

COVID-19 and Thrombosis: Clinical Aspects

In coronavirus disease 2019 (COVID-19), thrombus formation is related to the pathogenesis of acute respiratory distress syndrome (ARDS) and the progression of clinical symptoms. Severe damage to vascular endothelial cells and the associated cytokine storm after SARS-CoV-2 infection cause thrombogenesis and contribute to the development of more severe and unique thromboses compared to other infectious diseases. Thromboses occur more often in critically ill patients. In addition to pulmonary thromboembolism (PE) and deep vein thrombosis, acute myocardial infarction, peripheral arterial thrombosis, and aortic thrombosis have also been reported. In PE, thrombi develop in both pulmonary arteries and alveolar capillaries. These, together with intraalveolar fibrin deposition, interfere with effective gaseous exchange in the lungs and exacerbate the clinical symptoms of ARDS in patients with COVID-19. Pharmacological thromboprophylaxis is recommended for all hospitalized patients to prevent both thrombosis and aggravation of ARDS, and other organ failures. Although the pediatric population is mostly asymptomatic or develops mild disease after SARS-CoV-2 infection, a new inflammatory disorder affecting the cardiovascular system, multisystem inflammatory syndrome in children (MIS-C), has been reported. Similar to Kawasaki disease, acute myocarditis, coronary vasculitis, and aneurysms are typically seen in MISC, although these two are now considered distinct entities. A similar acute myocarditis is also observed in young male adults, in which a hyperinflammatory state after SARS-CoV-2 infection seems to be involved. Several side effects following vaccination against COVID-19 have been reported, including vaccine-induced immune thrombotic thrombocytopenia and acute myocarditis. Although these could be serious and life-threatening, the cases are very rare, thus, the benefits of immunization still outweigh the risks.

Host genetics impact on SARS-CoV-2 vaccine-induced immunoglobulin levels and dynamics: The role of TP53, ABO, APOE, ACE2, HLA-A, and CRP genes

Background: Development and worldwide availability of safe and effective vaccines against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) to fight severe symptoms of coronavirus disease 2019 (COVID-19) and block the pandemic have been a great achievement and stimulated researchers on understanding the efficacy and duration of different vaccine types. Methods: We investigated the levels of anti-SARS-CoV-2 antibodies (IgG) and neutralizing antibodies (NAbs) in 195 healthy adult subjects belonging to the staff of the University-Hospital of Ferrara (Italy) starting from 15 days up to 190 days (about 6 months) after the second dose of the BNT162b2 (Pfizer-BioNTech) mRNA-based vaccine (n = 128) or ChAdOx1 (AstraZeneca) adenovirus-based vaccine (n = 67) using a combined approach of serological and genomics investigations. Results: A strong correlation between IgG and NAb levels was detected during the 190 days of follow-up (r 2 = 0.807; p < 0.0001) and was confirmed during the first 90 days (T1) after vaccination (r 2 = 0.789; p = 0.0001) and 91-190 days (T2) after vaccination (r 2 = 0.764; p = 0.0001) for both vaccine types (r 2 = 0.842; p = 0.0001 and r 2 = 0.780; p = 0.0001 for mRNA- and adenovirus-based vaccine, respectively). In addition to age (p < 0.01), sex (p = 0.03), and type of vaccine (p < 0.0001), which partially accounted for the remarkable individual differences observed in the antibody levels and dynamics, interesting genetic determinants appeared as significant modifiers of both IgG and NAb responses among the selected genes investigated (TP53, rs1042522; APOE, rs7412/rs429358; ABO, rs657152; ACE2, rs2285666; HLA-A rs2571381/rs2499; CRP, rs2808635/rs876538; LZTFL1, rs35044562; OAS3, rs10735079; SLC6A20, rs11385942; CFH, rs1061170; and ACE1, ins/del, rs4646994). In detail, regression analysis and mean antibody level comparison yielded appreciable differences after genotype stratification (P1 and P2, respectively, for IgG and NAb distribution) in the whole cohort and/or in the mRNA-based vaccine in the following genes: TP53, rs1042522 (P1 = 0.03; P2 = 0.04); ABO, rs657152 (P1 = 0.01; P2 = 0.03); APOE, rs7412/rs429358 (P1 = 0.0018; P2 = 0.0002); ACE2, rs2285666 (P1 = 0.014; P2 = 0.009); HLA-A, rs2571381/rs2499 (P1 = 0.02; P2 = 0.03); and CRP, rs2808635/rs876538 (P1 = 0.01 and P2 = 0.09). Conclusion: High- or low-responsive subjects can be identified among healthy adult vaccinated subjects after targeted genetic screening. This suggests that favorable genetic backgrounds may support the progression of an effective vaccine-induced immune response, though no definite conclusions can be drawn on the real effectiveness ascribed to a specific vaccine or to the different extent of a genotype-driven humoral response. The interplay between data from the polygenic predictive markers and serological screening stratified by demogeographic information can help to recognize the individual humoral response, accounting for ethnic and geographical differences, in both COVID-19 and anti-SARS-CoV-2 vaccinations.

COVID-19 Vaccination Is Associated with a Better Outcome in Acute Ischemic Stroke Patients: A Retrospective Observational Study

Background: It is unclear whether and how COVID-19 vaccination may affect the outcome of patients with acute ischemic stroke (AIS). We investigated this potential association in a retrospective study by comparing previously vaccinated (VAX) versus unvaccinated (NoVAX) stroke patients. Methods: We collected clinical reports for all consecutive AIS patients admitted to our hospital and evaluated the outcome predictors in VAX and NoVAX groups. Adjustments were made for possible confounders in multivariable logistic regression analysis, and adjusted hazard ratios were calculated. Results: A total of 466 AIS patients (287 VAX and 179 NoVAX) were included in this study. The NIHSS score at discharge and mRS score at a 3-month follow-up visit were significantly lower in VAX patients compared to NoVAX patients (p < 0.001). Good outcomes (mRS 0−2) were significantly associated with COVID-19 vaccination before AIS (adjusted hazard ratio, 0.400 [95% CI = 0.216−0.741]). Conclusions: The observation that COVID-19 vaccination can influence the outcome of AIS provides support for further studies investigating the role of immunity in ischemic brain damage.

Acquired Thrombotic Thrombocytopenic Purpura After BNT162b2 COVID-19 Vaccine: Case Report and Literature Review

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy that is deadly if not treated promptly. The treatment of choice in patients presenting with TTP is plasma exchanges. However, immunosuppressive therapy and caplacizumab have significantly improved outcomes in TTP. This microangiopathy is classically divided into 2 entities: hereditary and acquired TTP (aTTP), caused by an autoantibody against ADAMTS 13. We present a case study of a patient wth TTP occurring after a second dose of the BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine along with a review of the literature. A 55-year-old patient presented with gastrointestinal symptoms, anemia, and severe thrombocytopenia. The blood film revealed the presence of schistocytes. A diagnosis of aTTP was established because the patient had severe ADAMTS 13 deficiency and autoantibodies against ADAMTS 13 were positive. This episode occurred 10 days after the patient received the COVID-19 vaccine. The patient received plasma exchanges, prednisone, rituximab, and caplacizumab and achieved complete remission. Ten patients with aTTP induced by the COVID-19 vaccine have been reported in the literature. Most of these situations occurred after the second dose of COVID-19 vaccine, and 7 patients were noted to have received the BNT162b2 vaccine. Caplacizumab was used in 6 patients, and complete remission was achieved in 8 patients.

Potential mechanisms of vaccine-induced thrombosis

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a rare syndrome characterized by high-titer anti-platelet factor 4 (PF4) antibodies, thrombocytopenia and arterial and venous thrombosis in unusual sites, as cerebral venous sinuses and splanchnic veins. VITT has been described to occur almost exclusively after administration of ChAdOx1 nCoV-19 and Ad26.COV2.S adenovirus vector- based COVID-19 vaccines. Clinical and laboratory features of VITT resemble those of heparin-induced thrombocytopenia (HIT). It has been hypothesized that negatively charged polyadenylated hexone proteins of the AdV vectors could act as heparin to induce the conformational changes of PF4 molecule that lead to the formation of anti-PF4/polyanion antibodies. The anti-PF4 immune response in VITT is fostered by the presence of a proinflammatory milieu, elicited by some impurities found in ChAdOx1 nCoV-19 vaccine, as well as by soluble spike protein resulting from alternative splice events. Anti-PF4 antibodies bind PF4, forming immune complexes which activate platelets, monocytes and granulocytes, resulting in the VITT's immunothrombosis. The reason why only a tiny minority of patents receiving AdV-based COVID-19 vaccines develop VITT is still unknown. It has been hypothesized that individual intrinsic factors, either acquired (i.e., pre-priming of B cells to produce anti-PF4 antibodies by previous contacts with bacteria or viruses) or inherited (i.e., differences in platelet T-cell ubiquitin ligand-2 [TULA-2] expression) can predispose a few subjects to develop VITT. A better knowledge of the mechanistic basis of VITT is essential to improve the safety and the effectiveness of future vaccines and gene therapies using adenovirus vectors.

Cerebral venous sinus thrombosis following intracerebral hemorrhage after COVID ‐19 AstraZeneca vaccination: A case report

The patient was a 55‐year‐old female patient who presented with sudden onset of left hemiplegia, facial hemiparesis, and hypoesthesia. She has received her first dose of the AstraZeneca COVID‐19 vaccine. This case indicates that vaccination may raise the hypercoagulable state even in a condition of post‐ICH and anticoagulant prophylaxis.