Cerebral venous sinus thrombosis in the setting of COVID-19 vaccination: a systematic review and meta-analysis

Current update on the neurological manifestations of long COVID: more questions than answers

Since the outbreak of the COVID-19 pandemic, there has been a global surge in patients presenting with prolonged or late-onset debilitating sequelae of SARS-CoV-2 infection, colloquially termed long COVID. This narrative review provides an updated synthesis of the latest evidence on the neurological manifestations of long COVID, discussing its clinical phenotypes, underlying pathophysiology, while also presenting the current state of diagnostic and therapeutic approaches. Approximately one-third of COVID-19 survivors experience prolonged neurological sequelae that persist for at least 12-months post-infection, adversely affecting patients' quality of life. Core neurological manifestations comprise fatigue, post-exertional malaise, cognitive impairment, headache, lightheadedness ('brain fog'), sleep disturbances, taste or smell disorders, dysautonomia, anxiety, and depression. Some of these features overlap substantially with those reported in post-intensive-care syndrome, myalgic encephalomyelitis/chronic fatigue syndrome, fibromyalgia, and postural-orthostatic-tachycardia syndrome. Advances in data-driven research utilizing electronic-health-records combined with machine learning and artificial intelligence have propelled the identification of long COVID sub-phenotypes. Furthermore, the evolving definitions reflect the dynamic conceptualization of long COVID in both research and clinical contexts. Although the underlying pathophysiology remains incompletely elucidated, neuroinflammatory responses, endotheliopathy, and metabolic imbalances, rather than direct viral neuroinvasion, are implicated in neurological sequelae. Genetic susceptibility has also emerged as a potential risk factor. While major limitations remain with existing definitions, collaborative strategies to standardize diagnostic approaches are needed. Current therapeutic paradigms advocate for multimodal approaches, integrating pharmacological and non-pharmacological interventions along with comprehensive rehabilitation programs. Although preliminary evidence of therapeutic efficacy has been provided by a number of clinical trials, methodological constraints limit the generalizability of this evidence. Preventive measures, notably vaccination, have proven integral for reducing the global burden of long COVID. Considering the healthcare and socioeconomic repercussions incurred by long COVID worldwide, international collaborative initiatives are warranted to address the remaining challenges in diagnosing and managing patients presenting with neurological sequelae. See also the graphical abstract(Fig. 1).

Nationwide Cohort observational study on the safety and efficacy of COVID-19 vaccination in patients with Moyamoya disease

The safety and efficacy of coronavirus disease 2019 (COVID-19) vaccination in patients diagnosed with Moyamoya disease (MMD) have not been established. Using National Health Insurance Service data, this study analyzed the occurrence of stroke-related events and mortality following COVID-19 vaccination among patients diagnosed with MMD from 2008 to 2020. Among 10,297 MMD patients, 296 (2.9%) experienced events and 175 (1.7%) died in 2021. Significant risk factors for events included ages 50-59 (Odds Ratio [OR] 3.29; P = 0.022) and 60 or above (OR 5.20; P = 0.001) (reference group: age in 20s), low BMI (OR 2.00; P = 0.011), previous stroke (OR 1.96; P < 0.001), and COVID-19 infection (OR 2.28; P = 0.034). Female (OR 0.64 [95% CI 0.50-0.82]; p = 0.011), revascularization surgery (RS) (OR 0.38 [95% CI 0.21-0.70]; p < 0.001), and vaccination (OR 0.17 [95% CI 0.13-0.22]; p < 0.001) were associated with reduced odds of stroke-related events. For mortality, significant risks were age over 60 (OR 7.09; P = 0.008), low BMI (OR 3.87; P = 0.001), and prior stroke (OR 1.74; p = 0.004), while being female, RS (OR 0.41; P = 0.022), and vaccination (OR 0.12; P < 0.001) were associated with a lower frequency of mortality. mRNA vaccines were associated with a significantly lower incidence of events, mortality, and COVID-19 infections compared to vector vaccines. COVID-19 vaccination is linked to reduced stroke-related events and mortality in MMD patients, with mRNA vaccines showing a significantly lower incidence compared to vector vaccines. COVID-19 infection raises the risk of events, underscoring the benefit of vaccination.

Cerebral venous thrombosis: a practical review

The evolution of the Coronavirus Disease-2019 pandemic and its vaccination raised more attention to cerebral venous thrombosis (CVT). Although CVT is less prevalent than arterial stroke, it results in larger years of life lost. CVT is more common in women and young patients. Predisposing factors are categorized as transient factors such as pregnancy, puerperium, oral contraceptive pills, trauma, and dehydration; and permanent factors such as neoplastic, vasculitic, thrombophilic, hematologic conditions, infectious causes such as severe acute respiratory syndrome coronavirus-2 infection and HIV. The most common manifestations are headache, seizures, focal neurologic deficits, altered level of consciousness, and cranial nerve palsies. The most common syndromes are stroke-like, raised-intracranial-pressure (ICP), isolated-headache, and encephalopathy, which may have overlaps. Diagnosis is mostly based on computed tomography, magnetic resonance imaging, and their respective venous sequences, supported by blood results abnormalities such as D-dimer elevation. Treatment includes the prevention of propagation of current thrombus with anticoagulation (heparin, or low molecular weight heparinoids and then warfarin, or direct oral anticoagulants), decreasing ICP (even by decompressive craniotomy), and treatment of specific underlying diseases.

Blood Coagulation and Thrombotic Disorders following SARS-CoV-2 Infection and COVID-19 Vaccination

Although abundant data confirm the efficacy and safety profile of the developed vaccines against COVID-19, there are still some concerns regarding vaccination in high-risk populations. This is especially valid for patients susceptible to thrombotic or bleeding events and hesitant people due to the fear of thrombotic incidents following vaccination. This narrative review focuses on various inherited and acquired thrombotic and coagulation disorders and the possible pathophysiologic mechanisms interacting with the coagulation system during immunization in view of the currently available safety data regarding COVID-19 vaccines. Inherited blood coagulation disorders and inherited thrombotic disorders in the light of COVID-19, as well as blood coagulation and thrombotic disorders and bleeding complications following COVID-19 vaccines, along with the possible pathogenesis hypotheses, therapeutic interventions, and imaging for diagnosing are discussed in detail. Lastly, the lack of causality between the bleeding and thrombotic events and COVID-19 vaccines is debated, but still emphasizes the importance of vaccination against COVID-19, outweighing the minimal risk of potential rare adverse events associated with coagulation.

Cerebral Venous Thrombosis in Young Adults: Unknown Origins

Cerebral venous thrombosis (CVT) is a relatively rare neurological disorder that may result in significant morbidity if not diagnosed and managed promptly. The clinical presentation of CVT is nonspecific and highly variable with acute, subacute, or chronic onset. It most often presents as a headache but may present with focal neurological symptoms, symptoms of intracranial hypertension, or encephalopathy. The predisposing factors for CVT are mainly acquired and genetic hypercoagulable conditions. However, the epidemiology, predisposing factors, and clinical presentation of CVT are not clearly established given the rare nature of the condition. We present a case series of three young patients who did not have any classic underlying etiology for CVT or any prior diagnosis of venous thrombosis. We want to report this case series to show that a high index of suspicion should be maintained regardless of the absence of risk factors.

Neurological Disorders following COVID-19 Vaccination

Nowadays, people all over the world have been receiving different types of coronavirus disease 2019 (COVID-19) vaccines. While their effectiveness has been well recognized, various post-vaccination disorders are not fully understood. In this review, we discuss neurological disorders related to vascular, immune, infectious, and functional factors following COVID-19 vaccination, and attempt to provide neuroscientists, psychiatrists, and vaccination staff with a reference for the diagnosis and treatment of these diseases. These disorders may present as a recurrence of previous neurological disorders or new-onset diseases. Their incidence rate, host and vaccine characteristics, clinical manifestations, treatment, and prognosis differ significantly. The pathogenesis of many of them remains unclear, and further studies are needed to provide more evidence. The incidence rate of severe neurological disorders is relatively low, most of which are reversible or treatable. Therefore, the benefits of vaccination outweigh the risk of COVID-19 infection, especially among fragile populations.

Extensive Cerebral Venous Sinus Thrombosis Post COVID-19 Vaccination

Extensive cerebral sinus thrombosis following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is rare. We report the case of a 42-year-old man who presented with a severe generalized headache that was not relieved by analgesics for nine days. It started four days after he received the third dose of BNT162b2 (BioNTech/Pfizer). He also complained of numbness at the back of the neck, vomiting, mild blurring of vision, and diplopia. The visual acuity (VA) in the right eye was 6/9 (improved to 6/7.5 with a pinhole) and 6/6 in the left eye. He was not able to abduct both eyes and noticed a double image at lateral gaze. Fundoscopy showed swollen optic discs with the presence of disc hemorrhages. A computed tomography venogram (CTV) of the brain showed loss of normal signal void with filling defects in the superior sagittal sinus, straight sinus, bilateral transverse sinuses, bilateral sigmoid sinuses, and bilateral internal jugular veins. The nasopharyngeal swab sample was negative for SARS-CoV-2. His platelet was normal (271x10⁹/L) and his coagulation profile was normal. Workup for connective tissue disease was negative. He was diagnosed with extensive cerebral vascular thrombosis post-vaccination. He received a one-week course of subcutaneous clexane, followed by oral anticoagulant treatment. After treatment, his headache was relieved, and the diplopia subsided. The venous thrombosis was partially resolved. Both the swollen optic discs improved, and his VA improved to 6/6 in both eyes.

Comparative risk of cerebral venous sinus thrombosis (CVST) following COVID-19 vaccination or infection: A national cohort study using linked electronic health records

To inform the public and policy makers, we investigated and compared the risk of cerebral venous sinus thrombosis (CVST) after SARS-Cov-2 vaccination or infection using a national cohort of 2,643,699 individuals aged 17 y and above, alive, and resident in Wales on 1 January 2020 followed up through multiple linked data sources until 28 March 2021. Exposures were first dose of Oxford-ChAdOx1 or Pfizer-BioNTech vaccine or polymerase chain reaction (PCR)-confirmed SARS-Cov-2 infection. The outcome was an incident record of CVST. Hazard ratios (HR) were calculated using multivariable Cox regression, adjusted for confounders. HR from SARS-Cov-2 infection was compared with that for SARS-Cov-2 vaccination. We identified 910,556 (34.4%) records of first SARS-Cov-2 vaccination and 165,862 (6.3%) of SARS-Cov-2 infection. A total of 1,372 CVST events were recorded during the study period, of which 52 (3.8%) and 48 (3.5%) occurred within 28 d after vaccination and infection, respectively. We observed slight non-significant risk of CVST within 28 d of vaccination [aHR: 1.34, 95% CI: 0.95-1.90], which remained after stratifying by vaccine [BNT162b2, aHR: 1.18 (95% CI: 0.63-2.21); ChAdOx1, aHR: 1.40 (95% CI: 0.95-2.05)]. Three times the number of CVST events is observed within 28 d of a positive SARS-Cov-2 test [aHR: 3.02 (95% CI: 2.17-4.21)]. The risk of CVST following SARS-Cov-2 infection is 2.3 times that following SARS-Cov-2 vaccine. This is important information both for those designing COVID-19 vaccination programs and for individuals making their own informed decisions on the risk-benefit of vaccination. This record-linkage approach will be useful in monitoring the safety of future vaccine programs.

Safety of COVID-19 Vaccines: Spotlight on Neurological Complications

The COVID-19 pandemic has led to unprecedented demand on the global healthcare system. Remarkably, at the end of 2021, COVID-19 vaccines received approvals for human use in several countries worldwide. Since then, a solid base for response in the fight against the virus has been placed. COVID-19 vaccines have been shown to be safe and effective drugs. Nevertheless, all kinds of vaccines may be associated with the possible appearance of neurological complications, and COVID-19 vaccines are not free from neurological side effects. Neurological complications of COVID-19 vaccination are usually mild, short-duration, and self-limiting. However, severe and unexpected post-vaccination complications are rare but possible events. They include the Guillain-Barré syndrome, facial palsy, other neuropathies, encephalitis, meningitis, myelitis, autoimmune disorders, and cerebrovascular events. The fear of severe or fatal neurological complications fed the "vaccine hesitancy" phenomenon, posing a vital communication challenge between the scientific community and public opinion. This review aims to collect and discuss the frequency, management, and outcome of reported neurological complications of COVID-19 vaccines after eighteen months of the World Health Organization's approval of COVID-19 vaccination, providing an overview of safety and concerns related to the most potent weapon against the SARS-CoV-2.