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Background: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare but severe complication following vaccination with adenovirus vector-based COVID-19 vaccines. Antibodies directed against platelet factor 4 (PF4) are thought to be responsible for platelet activation and subsequent thromboembolic events in these patients. Since a single vaccination does not lead to sufficient immunization, subsequent vaccinations against COVID-19 have been recommended. However, concerns exist regarding the possible development of a new thromboembolic episode after subsequent vaccinations in VITT patients. Methods: We prospectively analyzed follow-up data from four VITT patients (three women and one man; median age, 44 years [range, 22 to 62 years]) who subsequently received additional COVID-19 vaccines. Platelet counts, anti-PF4/heparin antibody level measurements, and a functional platelet activation assay were performed at each follow-up visit. Additionally, we conducted a literature review and summarized similar reports on the outcome of subsequent vaccinations in patients with VITT. Results: The patients had developed thrombocytopenia and thrombosis 4 to 17 days after the first vaccination with ChAdOx1 nCoV-19. The optical densities (ODs) of anti-PF4/heparin antibodies decreased with time, and three out of four patients tested negative within 4 months. One patient remained positive even after 10 months post first vaccination. All four patients received an mRNA-based vaccine as a second vaccination against SARS-CoV-2. No significant drop in platelet count or new thromboembolic complications were observed during follow-up. We identified seven publications reporting subsequent COVID-19 vaccination in VITT patients. None of the patients developed thrombocytopenia or thrombosis after the subsequent vaccination. Conclusion: Subsequent vaccination with an mRNA vaccine appears to be safe in VITT patients. [ABSTRACT FROM AUTHOR]

Gender has been shown to be an important variable in cerebral venous thrombosis (CVT) risk and significantly influences its clinical manifestations and outcome. The aim of our study was to investigate the gender-specific risk factor profile and clinical picture of this rare cerebrovascular disorder. Materials and methods: We retrospectively reviewed the medical records of 89 consecutive cases of CVT at a tertiary neurology clinic in Târgu Mures, Romania, between June 2009 and January 2021 to analyze the gender-related differences in etiology, clinical presentation, and outcome. Results: Women comprised 62.5% of the cohort. Females were significantly younger than males (37.3 years versus 48.8 years, respectively, p = 0.001), and the main risk factors were hormone related in 37.9% of the cases, followed by primary thrombophilia (34.4%), smoking (25.8%), obesity (17.2%), infections (17.2%), mechanical factors (17.2%), cancer (8.6%), systemic autoimmune disorders (8.6%), and hematological disorders (8.6%). In male patients, the main risk factors were smoking (41.9%), primary thrombophilia (29%), infections (22.6%), heavy alcohol consumption (16.1%), and venous thromboembolism in the medical history (12.9%). Frequency of headache was higher in females than in males (75.9% versus 67.7%), whereas frequency of coma (6.5% in males versus 1.7% in females) and dizziness (19.4% in males versus 10.3% in females) was higher in males. CVT onset was acute in 41.4% of females and 38.7% of males. The Rankin score at discharge was significantly lower in females compared with males (0.6 versus 1.6), reflecting a more favorable short-term outcome. Mortality was 6.4% in males and 1.7% in females. Conclusions: CVT is a multifactorial disorder that has a broad spectrum of risk factors with important gender-related differences in clinical manifestation and prognosis. Female patients, especially those with hormone-related risk factors, have a more favorable outcome than male patients. [ABSTRACT FROM AUTHOR]