key: cord-0910519-2el8q1y2
authors: Garg, Ravindra Kumar; Paliwal, Vimal Kumar
title: Spectrum of neurological complications following COVID-19 vaccination
date: 2021-10-31
journal: Neurol Sci
DOI: 10.1007/s10072-021-05662-9
sha: cd16d1c2d6e0353ef8d8feaee0a7cd88cb18a951
doc_id: 910519
cord_uid: 2el8q1y2

COVID-19 vaccines have brought us a ray of hope to effectively fight against deadly pandemic of COVID-19 and hope to save lives. Many vaccines have been granted emergency use authorizations by many countries. Post-authorization, a wide spectrum of neurological complications is continuously being reported following COVID-19 vaccination. Neurological adverse events following vaccination are generally mild and transient, like fever and chills, headache, fatigue, myalgia and arthralgia, or local injection site effects like swelling, redness, or pain. The most devastating neurological post-vaccination complication is cerebral venous sinus thrombosis. Cerebral venous sinus is frequently reported in females of childbearing age, generally following adenovector-based vaccination. Another major neurological complication of concern is Bell’s palsy that was reported dominantly following mRNA vaccine administration. Acute transverse myelitis, acute disseminated encephalomyelitis, and acute demyelinating polyneuropathy are other unexpected neurological adverse events that occur as result of phenomenon of molecular mimicry. Reactivation of herpes zoster in many persons, following administration of mRNA vaccines, has been also recorded. Considering the enormity of recent COVID-19-vaccinated population, the number of serious neurological events is miniscule. Large collaborative prospective studies are needed to prove or disprove causal association between vaccine and neurological adverse events occurring vaccination.

Neurological adverse events following COVID-19 vaccination are generally mild and transient, like fever/chills, headache, fatigue, myalgia and arthralgia, or local injection site effects like swelling, redness, or pain. These mild neurological symptoms are common following administration of all kinds of COVID-19 vaccines.

Anxiety-related events, like feeling of syncope and/or dizziness, are particularly common. For example, Centers for Disease Control and Prevention, in a report published on April 30, 2021, recorded 64 anxiety-related events (syncope in 17) among 8,624 Janssen COVID-19 vaccine recipients. None of the event was labeled as serious [4] .

In Mexico (data available in form of preprint) among 704 003 subjects who received first doses of the Pfizer-BioNTech mRNA COVID-19 vaccine, 6536 adverse events following immunization were recorded. Among those, 4258 (65%) had at least one neurologic manifestation, mostly (99.6%) mild and transient. These events included headache (62·2%), transient sensory symptoms (3·5%), and weakness (1%). In this study, there were only 17 serious adverse events, seizures (7) , functional syndromes (4), Guillain-Barré syndrome (3) , and transverse myelitis (2) [5] .

In South Korea, Kim and co-workers collected data of post-vaccination adverse events following first dose of adenovirus vector vaccine ChAdOx1 nCoV-19 (1,403 subjects) and mRNA vaccine BNT162b2 (80 subjects) vaccinations. Data were collected daily for 7 days after vaccination. Authors noted that 91% of adenovirus-vectored vaccine and 53% of mRNA vaccine recipients had mild adverse reactions, like injection-site pain, myalgia, fatigue, headache, and fever [6] . A mobile-based survey among healthcare workers (265 respondents) who received both doses of the BNT162b2 mRNA vaccine was conducted. The most common adverse effects were muscle ache, fatigue, headache, chills, and fever. Adverse reactions were higher after the second dose compared with that after the first dose [7] .

Headache is one of the most frequent mild neurological complaints reported by a large number of COVID-19 vaccine recipients, soon after they receive vaccine.

A review of headache characteristic noted that among 2464 participants, headache begun 14.5 ± 21.6 h after Astra-Zeneca adenovirus vector vaccine COVID-19 vaccination and persisted for 16.3 ± 30.4 h. Headaches, in majority, were moderate to severe in intensity and generally localized to frontal region. Common accompanying symptoms were fatigue, chills, exhaustion, and fever [8] . In a multicenter observational cohort study, Göbel et al. recorded clinical characteristic of headache occurring after the mRNA BNT162b2 mRNA COVID-19 vaccination. Generally, headache started 18.0 ± 27.0 h after vaccination and persisted for 14.2 ± 21.3 h. In majority, the headaches were bifrontal or temporal, dull aching character and were moderate to severe in intensity. The common accompanying symptoms were fatigue, exhaustion, and muscle pain [8] .

Serious adverse reaction following immunization is defined as a post-vaccination event that are either life-threatening, requires hospitalization, or result in severe disability. The World Health Organization listed Guillain-Barré syndrome, seizures, anaphylaxis, syncope, encephalitis, thrombocytopenia, vasculitis, and Bell's palsy as serious neurologic adverse events. Instances of serious adverse events following COVID-19 vaccinations are continuously pouring in the current scientific literature and are source of vaccine hesitancy in many persons [9] (Fig. 1 ).

Functional neurological disorders are triggered by physical/ emotional stress following an injury, medical illness, a surgery, or vaccination. Functional neurological disorders often remain misdiagnosed despite extensive workup.

After availability of COVID-19 vaccine, many YouTube videos depicted continuous limb and trunk movements and difficulty walking immediately after COVID-19 vaccine administration. These videos were of concern as they were the source of "vaccine hesitancy" [10] . Kim and colleagues reviewed several such social media videos demonstrating motor movements consistent with functional motor symptoms occurring after administration of COVID-19 vaccine. Motor movements were bizarre asynchronous and rapidly variable in frequency and amplitude consistent with functional neurological disorder. The Functional Neurological Disorder Society has lately clarified that movement disorder is consistent with functional in nature. The spread of these videos are important because these functional disorders created concerns for vaccine hesitancy [11] .

Several other kinds of functional neurological disorders have also been reported. Butler and colleagues described two young ladies, who presented with functional motor deficits mimicking stroke. Both these patients had variability in weakness and had many non-specific symptoms. A detailed workup and neuroimaging failed to demonstrate any specific abnormality [12] . Ercoli and colleagues described a middle-aged man who, immediately after vaccine administration, reported bilateral facial paralysis along with failure to blink. These manifestations resolved quickly within 40 min. Immediately after administration of second dose of vaccine, he complained of respiratory distress and swollen tongue. Again, all these symptoms resolved quickly following treatment with corticosteroids, however, he developed new symptoms in the form of right hemiparesis. Two weeks later, he developed facial hypoesthesia. A detailed workup of the patient failed to demonstrate any abnormality. A diagnosis of functional neurological disorder was, finally, made [13] .

As a matter of concern, increasing number of reports about adenoviral vector vaccine-induced cerebral vascular adverse events, like cerebral venous thrombosis, arterial stroke, and intracerebral hemorrhage, is getting published in leading medical journals. These reports are alarming as post-vaccination vascular events culminate either in severe disability or death. Vaccine-induced cerebral vascular adverse events are generally associated with severe immune-mediated thrombotic thrombocytopenia. Thrombocytopenia generally clinically manifests within 5 to 30 days after administration of adenovirus vector-based vaccines. In post-vaccination thrombotic thrombocytopenia, a picture similar to that of heparin-induced thrombocytopenia is encountered. When heparin binds platelet factor 4, there is generation of antibodies against platelet factor 4. Antibodies against platelet factor 4 result in platelet destruction and trigger the intravascular blood clotting [14] . The post-mortem examination, in patients with vaccine-induced thrombocytopenia, demonstrated extensive involvement of large venous vessels. Microscopic findings showed vascular thrombotic occlusions occurring in the vessels of multiple body organs along with marked inflammatory infiltration [15] . The vector-based vaccines contain genetic material of SARS-COV-2 that is capable of encoding the spike glycoprotein. Possibly, leaked genetic material binds to platelet factor 4 that subsequently activates formation of autoantibodies. These autoantibodies destroy platelets [16, 17] .

Cerebral venous thrombosis is the one of the most feared devastating COVID-19 vaccine-associated neurological complication. Cerebral venous thrombosis should be suspected in all vaccinated patients, who has persistent headache. Headache is generally unresponsive to the analgesics, and some patients may have focal neurological deficits. Affected patients are generally females of younger ages (Table 1 ) .

In Europe, since March 2021, cases of cerebral venous thrombosis started pouring in following COVID-19 vaccination, particularly after administration of viral vector based (AstraZeneca ChAdOx1 nCoV-19 and the Johnson and Johnson Ad26. COV2.S) vaccines [22] . Scully and colleagues recently reported findings of 23 patients, who presented with thrombosis and thrombocytopenia (platelet counts below 10 × 109/L). These patients developed thrombosis and thrombocytopenia 6 to 24 days after they received the first dose of the viral vector-based vaccines. In a significant observation, authors, in majority of patients, demonstrated the presence of autoantibodies against platelet factor 4. Additionally, D-dimer levels were found elevated [20] . Tiede and co-workers reported five German cases of prothrombotic immune thrombocytopenia after vaccination with viral vector-based vaccine (Vaxzevria). In these patients, acute vascular events clinically manifested as cerebral venous sinus thrombosis, splanchnic vein thrombosis, arterial cerebral thromboembolism, and/or thrombotic microangiopathy within 2 weeks post vaccination. All five patients had low platelet counts and markedly raised D-dimer. In all, autoantibodies against platelet factor 4 were also demonstrated [30] . Pottegård [48] .

Recently published National Institute for Health and Care Excellence (NICE) guidelines recommend that the patients with clinical diagnosis of vaccine-induced immune thrombocytopenia and thrombosis should be treated with intravenous administration of human immunoglobulin, at a dose of 1 g/ kg. If there is no response or there is further deterioration, second dose of human immunoglobulin should be given. In patients with insufficient response, methylprednisolone 1 g intravenously for 3 days or dexamethasone 20 to 40 mg for 4 days can be used [49] .

Heparin needs to be avoided, instead alternative anticoagulants like argatroban, bivalirudin, fondaparinux, rivaroxaban, or apixaban should be used for anticoagulation [49] [50] [51] . NICE guidelines further recommend that patients with very low platelet count should be treated either alone with a argatroban or a combination of argatroban and platelet transfusion [49] .

Several acute arterial events, like arterial thrombosis, intracerebral hemorrhage, transient global amnesia, and spinal artery ischemia, have also been reported following vaccination [31] .

Simpson and colleagues, in Scotland, estimated the incidence of vaccine-associated thrombocytopenia and vascular events following administration of first dose of viral vectorbased vaccine (ChAdOx1) or mRNA (BNT162b2 Pfizer-BioNTech or mRNA-1273 Moderna) vaccination. First dose of viral vector-based vaccine was associated with small enhanced risk of idiopathic thrombocytopenic purpura; in addition, up to 27 days after vaccination, there was possibility of an increased risk for thromboembolic and hemorrhagic events. No such adverse associations were noted with mRNA vaccines [52] . The reports of COVID-19 vaccine-related intracerebral hemorrhage and ischemic stroke are summarized in Table 2 [53] [54] [55] [56] [57] [58] [59] [60] [61] .

Athyros and Doumas reported a 71-year-old female. who developed intracerebral hemorrhage after she received the first dose of the Moderna mRNA vaccine. On the third post-vaccination day, the patient developed right hemiplegia, aphasia, and agnosia along with accelerated hypertension. Computed tomography revealed a hematoma in the left basal ganglia. On the 9th day, she died [53] .

In another report, Bjørnstad-Tuveng et al. described a young woman, who had a fatal cerebral event following vaccination with AstraZeneca's ChAdOx1 nCoV-19 vaccine. She was found to have severe thrombocytopenia. The patient died the next day of the event. Post-mortem examination revealed antibodies against platelet factor 4 and the presence of small thrombi in the transverse sinus, frontal lobe, and pulmonary artery [54] .

Bayas and co-workers described a case that presented with superior ophthalmic vein thrombosis, ischemic stroke, and immune thrombocytopenia, after administration of viral vector-based vaccine. Intravenous dexamethasone resulted in marked improvement in platelet count [56] . Al-Mayhani et al. described three cases of vaccine-induced thrombotic thrombocytopenia, all presented with arterial strokes. Authors opined that young patients with arterial stroke after receiving the COVID-19 vaccine should always be evaluated for vaccine-induced thrombotic thrombocytopenia. Other laboratory tests, like platelet count, D-dimers, fibrinogen level, and testing for platelet factor 4 antibodies, should also be performed [57] . Blauenfeldt et al. described a 60-year-old woman, who presented with intractable abdominal pain, 7 days after receiving the adenoviral (ChAdOx1) vector-based COVID-19 vaccine. Abdominal computed tomography revealed bilateral adrenal necrosis. Later, a massive right cerebral infarction, secondary to occlusion of the right internal carotid artery, occurred that led to death of the patient. Blood tests showed thrombocytopenia, elevated in D-dimer and platelet factor 4 antibodies [58] .

Many reports of acute brain disorders like encephalopathy, seizures, acute disseminated encephalopathy, neuroleptic malignant syndrome, and post-vaccine encephalitis were described secondary to COVID-19 vaccine. These are summarized in Table 3 [62] [63] [64] [65] [66] [67] [68] [69] [70] [71] [72] [73] [74] [75] .

Some patients developed encephalopathy following administration of COVID-19 vaccines. Acute encephalopathy is defined as rapidly evolving disorder of the brain. Acute encephalopathy clinically manifests either with delirium, decreased consciousness, or coma.

Delirium is characterized with fluctuating disturbance in attention and awareness. Zavala-Jonguitud and Pérez-García described an 89-year-old man, who developed delirium after mRNA vaccination. Within 24 h, patient developed confusion, fluctuating attention, anxiety, and inversion of the sleep-wake cycle. Patient had many comorbidities (diabetes mellitus, hypertension, and chronic kidney disease). Patient improved after he was treated with quetiapine [68] .

Neuroleptic malignant syndrome is a life-threatening complication of many antipsychotic drugs characterized by fever, altered mental status, muscle rigidity, and autonomic dysfunction. In an isolated report, neuroleptic malignant syndrome, in a 74-year-old female with dementia and bipolar disorder 16 days after COVID-19 vaccination, has been described [69] .

Acute disseminated encephalomyelitis (ADEM) is an acute inflammatory demyelinating disorder of the central nervous system. In the majority, ADEM is a post-infectious entity; in many cases, it even develops after vaccination [76] . In two cases, acute disseminated encephalomyelitis following COVID-19 vaccination has been reported. In first such case a 46-year-old woman received Sinovac inactivated SARS-CoV-2 vaccine before onset of clinical manifestations. Patient was presented with seizures, and magnetic resonance imaging revealed multiple, discrete T2/FLAIR periventricular. hyperintense lesions. Patient improved following methylprednisolone treatment [70] Another patient was a 24-year-old female who presented with encephalopathy along with limb weakness of 1-day duration. Two weeks prior, patient was vaccinated with inactivated SARS-CoV-2 vaccine. Magnetic resonance imaging revealed multiple, discrete T2/FLAIR hyperintense lesions in the brain. Patient improved following treatment with antiepileptics and intravenous immunoglobulins [71] .

Zuhorn et al. reported a case series 3 patients, who presented with post-vaccinal encephalitis, akin to autoimmune encephalitis, 7 to 11 days after administration of adenovirus-based ChAdOx1 nCov-19 vaccine. All patients fulfilled the diagnostic criteria for possible autoimmune encephalitis. One interesting case had presented with opsoclonus-myoclonus syndrome. Two patients presented with cognitive decline, seizures, and gait disorder. Neuroimaging did not reveal any abnormality. CSF pleocytosis was noted in all three patients. All patients responded well to corticosteroids [75] .

Acute transverse myelitis is an inflammatory spinal cord disorder that clinically manifests with the paraparesis/ quadriparesis, transverse sensory level, and bowel or bladder dysfunction. Acute transverse myelitis usually is a postinfectious disorder. Magnetic resonance imaging demonstrates T2/FLAIR hyperintensity extending several spinal cord segments. Autoimmunity via mechanism of molecular mimicry is usually responsible for spinal cord dysfunction. Adenoviral vector-based COVID-19 vaccines are more frequently associated with causation of transverse myelitis. In isolated cases, even inactivated virus vaccine and mRNA-based vaccines had precipitated acute demyelination spinal cord syndromes, like multiple sclerosis and neuromyelitis optica. Reports of myelitis associated with vaccination for SARS-CoV-2 are summarized in Table 4 [77] [78] [79] [80] [81] [82] [83] . Malhotra and colleagues reported a 36-year-old patient, who had short-segment myelitis 21 days after first dose of adenoviral vector-based (Oxford/AstraZeneca, COV-ISHIELD™) vaccine. Patient recovered completely after treatment with methylprednisolone [77] . Fitzsimmons and Nance reported another patient of acute transverse myelitis following Moderna vaccine (an mRNA vaccine). The 63-year-old patient developed symptoms of acute myelopathy within 24 h of vaccination. MRI revealed increased T2 cord signal seen in the distal spinal cord and conus. Patient improved considerably following treatment with methylprednisolone and intravenous immunoglobulin [78] .

Earlier, in phase III trial of Oxford/AstraZeneca vaccine, 2 patients had developed transverse myelitis. One of the case of transverse myelitis was reported 14 days after booster vaccination. The expert committee considered that this case was the most likely an idiopathic, short segment transverse myelitis. The second case was reported 68 days post-vaccination. Experts believed that in this case, transverse myelitis was not likely to be associated with vaccination. This patient was earlier diagnosed as a case of multiple sclerosis [84, 85] .

The pathogenesis of acute transverse myelitis following COVID-19 vaccination remains unknown. Possibly, SARS-CoV-2 antigens present in the COVID-19 vaccine or its adenovirus adjuvant induce immunological reaction in the spinal cord. The occurrence of 3 reported acute transverse myelitis adverse effects among 11,636 participants in the vaccine trials was considered high and a cause of concern [86] .

Several cases of Bell's palsy have occurred following COVID-19 vaccination. (Table 5 ) [87] [88] [89] [90] [91] [92] [93] [94] [95] . The instances of Bell's palsy are most often associated with mRNA vaccines [96] . Vaccine-associated Bell's palsy generally responds very well to the oral corticosteroids. The exact pathogenesis remains speculative.

In a case-control study, Shemer et al. compared clinical parameters of patients with Bell's palsy following mRNA vaccination with that of patients with Bell's palsy without vaccination. Out of 37 patients, 21 had received vaccination. Bell's palsy developed within 2 weeks following first dose of COVID-19 vaccination. There was no difference in any of the clinical parameter between vaccinated or unvaccinated groups [97] .

Earlier, in the Pfizer-BioNTech clinical trial, which included 44,000 participants, 4 people had Bell's palsy. No case of Bell's palsy was reported in the placebo arm. In the Moderna trial, which included 30,400 participants, 3 vaccine recipients reported Bell's palsy. One person was in the placebo arm [98] . An article, published in the Lancet, analyzed the combined phase 3 data of Pfizer and Moderna trials and noted that the rate of Bell's palsy was higher than expected [98] .

In isolated instances, mRNA vaccines were found associated with olfactory dysfunction and sixth cranial nerve palsy (Table 6 ) [99] [100] [101] [102] [103] [104] .

Olfactory dysfunction is the most frequent neurological complication of COVID-19. Konstantinidis and colleagues reported two cases of smell impairment after second dose of the BioNTechBNT162b2 vaccine (Pfizer) administration [51] .

Keir and colleagues reported phantosmia following administration of Pfizer COVID-19 vaccine. Patient complained of constantly "smelling smoke" and headaches. MRI of brain of the patient showed enhancement of the olfactory bulbs and bilateral olfactory tracts [100] .

Reyes-Capo et al. reported a 59-year-old lady, who presented with an abducen nerve palsy 2 days post-vaccination 

A variety of otologic manifestations has been noted following COVID-19 vaccination. Parrino and colleagues described three patients with sudden unilateral tinnitus following BNT162b2 mRNA vaccine administration. Tinnitus rapidly resolved in 2 cases. Wichova and colleagues in a retrospective review recorded 30 patients, who either had significantly exacerbated otologic symptoms or had a new symptom after getting mRNA vaccine. Post-vaccination otologic manifestations included hearing loss with tinnitus, dizziness, or with vertigo. In some patients, with Menière's disease or autoimmune inner ear disease, vaccine led to exacerbation of the pre-existing otologic symptoms [102, 105] .

Santovito and Pinna reported an unusual patient, who developed acute visual impairment following the 2nd dose of the Pfizer-BioNTech COVID-19 vaccine. Prior to visual symptoms, patient experienced unilateral headache. He also reported mild confusion, asthenia, and profound nausea. His symptoms got relieved after taking analgesics. Possibly, patient had an acute attack of migraine with aura that got precipitated by the vaccine [106] .

Guillain-Barré syndrome is a post-infectious disorder of peripheral nerve manifesting with lower motor neuron type of sensory-motor quadriparesis. Acute motor weakness is frequently preceded by an antecedent microbial infection. There are numerous reports indicating that COVID-19 infection can trigger Guillain-Barré syndrome. The US Food and Drug Administration has recently expressed its concern regarding a possible association between the Johnson and Johnson COVID-19 vaccine with Guillain-Barré syndrome [107] . After emergency use approvals, all kinds of COVID-19 vaccines were found associated with Guillain-Barré syndrome. Adenovector-based vaccines were more frequently associated with Guillain-Barré syndrome. Earlier, in phase 3 trial of Johnson and Johnson adenovirus vector-based COVID-19 vaccine, 2 patients developed Guillain-Barré syndrome. One patient belonged to vaccine group and other to placebo group. Both patients had Guillain-Barré syndrome within 2 weeks of receiving injections. The Guillain-Barré syndrome in the vaccine arm was preceded by chills, nausea, diarrhea, and myalgia [108, 109] . Post-vaccination Guillain-Barré syndrome generally affects older adults within 2 weeks of vaccine administration. Clinical presentation is similar to acute demyelinating neuropathy; nerve conduction studies show demyelinating pattern, and CSF examination shows cyto-albuminic dissociation. Many patients present only with facial diplegia. Response to immunotherapy is generally good. (Table 7 ) [110] [111] [112] [113] [114] [115] [116] [117] [118] [119] [120] [121] [122] [123] [124] [125] [126] .

Proposed pathogenesis of Guillain-Barré syndrome is an autoantibody-mediated immunological damage of peripheral nerves via mechanism of molecular mimicry between structural components of peripheral nerves and the microorganism. Lately, several cases of Guillain-Barré syndrome following COVID-19 vaccination have also been reported.

Waheed et al. described a 57-year-old female, who presented with painful neuropathy following administration of the mRNA COVID-19 vaccine. Patient subacutely presented with intense peripheral burning sensations. Electrodiagnostic studies were normal. Skin biopsy proved small fiber neuropathy. Patient responded to gabapentin. (Table 7 ) [127] .

Parsonage-Turner syndrome or neuralgic amyotrophy is clinically manifested with acute unilateral shoulder pain followed by brachial plexopathy. Parsonage-Turner syndrome is usually triggered by any infection, surgery, or rarely vaccination. In many reports, Parsonage-Turner syndrome has been described following COVID-19 vaccination. (Table 8 ) [128] [129] [130] .

Herpes zoster occurs following reactivation of varicella zoster virus. Patients with herpes zoster present with the classic maculopapular rash, which is unilateral, confined to a single dermatome. The rash disappears in 7 to 10 days. Postherpetic neuralgia is the frequent complication of herpes zoster, which is noted in 1 in 5 patients. McMahon and co-workers recorded 414 cutaneous reactions to mRNA COVID-19 vaccines, and 5 (1.9%) were diagnosed with herpes zoster [131] . Other types of COVID-19 vaccines are infrequently associated with post-vaccination reactivation of herpes zoster. It has been suggested that vaccine-induced immunomodulation, resulting in dysregulation of T cell function, is responsible for reactivation of herpes zoster virus [132, 133] . Reports of herpes zoster reactivation after vaccine against SARS-CoV-2 are summarized in Table 9 [134] [135] [136] [137] [138] [139] [140] [141] [142] .

There are reports, which have indicated that COVID-19 vaccines have potential to damage the skeletal muscles as well (Table 10 ) [143] [144] [145] [146] [147] . Tan and colleagues described a patient with a known carnitine palmitoyltransferase-II deficiency disorder, who developed fever, vomiting, shortness of breath, frank haematuria, myalgia and muscle weakness within four hours of receiving AstraZeneca COVID-19 vaccine [143] . Theodorou and colleagues described a 56-year-old woman who, 8 days after a second dose of vaccine administration, developed severe left upper arm pain along restricted shoulder movements. Her serum creatine kinase was elevated suggesting skeletal muscle damage. MRI revealed severely edematous deltoid muscles. Contrast-enhanced imaging demonstrated enhancement of deltoid muscles suggestive of myositis [146] .

Post-authorization, a wide spectrum of serious neurological complications has been reported following COVID-19 vaccination. The most devastating neurological complication is cerebral venous sinus thrombosis that has been reported in females of childbearing age following adenovector-based vaccines. Another major neurological complication of concern is Bell's palsy that was reported dominantly following mRNA vaccine administration. Transverse myelitis, acute disseminated encephalomyelitis, and Guillain-Barré syndrome are other severe unexpected post-vaccination complications that can occur as result of molecular mimicry and subsequent neuronal damage. Most of other serious neurological complications are reported in either in form of isolated case reports or small cases series. A causal association of these adverse events is controversial; large collaborative prospective studies are needed to prove causality.

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Peripheral facial nerve palsy following BNT162b2 (COVID-19) vaccination

Bell's Palsy after second dose of Pfizer COVID-19 vaccination in a patient with history of recurrent Bell's palsy

Bell's palsy following COVID-19 vaccination

Bell's palsy following a single dose of mRNA SARS-CoV-2 vaccine: a case report

2021 Bell's palsy following the Ad26.COV2.S COVID-19 vaccination

Sequential contralateral facial nerve palsies following COVID-19 vaccination first and second doses

Bell's palsy following COVID-19 vaccination with high CSF antibody response

Bell's palsy after 24 hours of mRNA-1273 SARS-CoV-2 vaccine

2021 Bell's palsy and SARS-CoV-2 vaccines-an unfolding story -authors' reply

Association of COVID-19 vaccination and facial nerve palsy: a case-control study

Bell's palsy and SARS-CoV-2 vaccines

Olfactory dysfunction after coronavirus disease 2019 (COVID-19) vaccination

Unique imaging findings of neurologic phantosmia following Pfizer-BioNtech COVID-19 vaccination: a case report

Acute abducens nerve palsy following COVID-19 vaccination

Tinnitus following COVID-19 vaccination: report of three cases

2021 The reversible tinnitus and cochleopathy followed first-dose Astra-Zeneca COVID-19 vaccination

QJM hcab210

Trigeminal and cervical radiculitis after tozinameran vaccination against COVID-19

Otologic manifestations after COVID-19 vaccination: the house ear clinic experience

Acute reduction of visual acuity and visual field after Pfizer-BioNTech COVID-19 vaccine 2nd dose: a case report

Covid-19: Regulators warn that rare Guillain-Barré cases may link to J&J and AstraZeneca vaccines

Guillain-Barré syndrome in the placebo and active arms of a COVID-19 vaccine clinical trial: temporal associations do not imply causality

Vaccines and Related Biological Products Advisory Committee Meeting

Neurological complications of COVID-19: Guillain-Barre syndrome following Pfizer COVID-19 vaccine

Guillain-Barré syndrome in the placebo and active arms of a COVID-19 vaccine clinical trial: temporal associations do not imply causality

Guillain-Barre syndrome following the first dose of the chimpanzee adenovirus-vectored COVID-19 vaccine, ChAdOx1

Post-COVID-19 vaccine Guillain-Barré syndrome; first reported case from Qatar. Authorea

Guillain-Barré syndrome following the first dose of SARS-CoV-2 vaccine: a temporal occurrence, not a causal association

Exacerbating Guillain-Barré syndrome eight days after vector-based COVID-19 vaccination

Guillain-Barré syndrome following ChAdOx1-S/nCoV-19 vaccine

Guillain-Barré syndrome variant occurring after SARS-CoV-2 vaccination

Guillain-Barré syndrome after COVID-19 vaccine: should we assume a causal Link?

Guillain-Barré syndrome in a 67-year-old male post COVID-19 vaccination

Case of Guillain-Barré syndrome following COVID-19 vaccine

Guillain-Barré syndrome following first injection of ChAdOx1 nCoV-19 vaccine: First report

Bilateral facial weakness with paraesthesia variant of Guillain-Barré syndrome following Vaxzevria COVID-19 vaccine

A case of acute demyelinating polyradiculoneuropathy with bilateral facial palsy after ChAdOx1 nCoV-19 vaccine

Facial diplegia: a rare, atypical variant of Guillain-Barré syndrome and Ad26

Guillain-Barré syndrome after COVID-19 vaccination

Bilateral facial weakness with paraesthesia variant of Guillain-Barré syndrome following Vaxzevria COVID-19 vaccine

Post COVID-19 vaccine small fiber neuropathy

Parsonage Turner syndrome after COVID-19 vaccination

2021 Painless idiopathic neuralgic amyotrophy after COVID-19 vaccination: a case report

Neuralgia amiotrófica secundaria a vacuna contra COVID-19 Vaxzevria (AstraZeneca) [Amyotrophic neuralgia secondary to Vaxzevria (AstraZeneca) COVID-19 vaccine

Cutaneous reactions reported after Moderna and Pfizer COVID-19 vaccination: a registry-based study of 414 cases

Herpes zoster after inactivated COVID-19 vaccine: a cutaneous adverse effect of the vaccine

Reply to: Herpes-Zoster reactivation after mRNA-1273 (Moderna) SARS-CoV-2 Vaccination

Ipsilateral herpes zoster after the first dose of BNT162b2 mRNA COVID-19 vaccine

Varicella-zoster virus reactivation after SARS-CoV-2 BNT162b2 mRNA vaccination: Report of 5 cases

Herpes zoster emergence following mRNA COVID-19 vaccine

Herpes zoster following inactivated COVID-19 vaccine: a coexistence or coincidence?

Herpes zoster following BNT162b2 mRNA Covid-19 vaccination in patients with autoimmune inflammatory rheumatic diseases: a case series

A rare case of shingles after COVID-19 vaccine: is it a possible adverse effect?

Herpes zoster following COVID-19 vaccine: report of 3 cases

Herpes Zoster following SARS-CoV-2 vaccination -a series of 4 cases

Letter to the editor: Herpes-Zoster reactivation after mRNA-1273 (Moderna) SARS-CoV-2 Vaccination

Carnitine palmitoyltransferase II deficiency and post-COVID vaccination rhabdomyolysis

Rhabdomyolysis secondary to COVID-19 vaccination

COVID-19 vaccine induced rhabdomyolysis: Case report with literature review

COVID-19 vaccine-related myositis

Myositis ossificans following COVID-19 vaccination