Case Reports of Acute Transverse Myelitis Associated With mRNA Vaccine for COVID-19

Central nervous system manifestations following vaccination against COVID-19

Coronavirus disease 2019 (COVID-19) vaccination has become the most effective countermeasure in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. However, vaccination is associated with side effects. This narrative review focuses on central nervous system (CNS) manifestations following COVID-19 vaccination and provides a summary of the potential underlying mechanisms and methods of diagnosis and management of the vaccination-related CNS manifestations. Headache, myalgia, optic neuritis, seizure, multiple sclerosis, acute disseminated encephalomyelitis and encephalitis, delirium, acute transverse myelitis, and stroke have been reported after COVID-19 vaccination. Constant headache and myalgia are common manifestations that may necessitate further clinical investigation for stroke. To limit consequences, it is imperative to follow standard treatment protocols for each neurological disorder following COVID-19 vaccination. Immunosuppressive medication can be helpful in the treatment of seizures following vaccination since the immune response is involved in their etiology. Clinicians should be aware of the manifestations after COVID-19 vaccination to respond promptly and effectively. Clinical guidelines for the management of CNS manifestations following COVID-19 vaccination are in high demand and would be useful in each new SARS-CoV-2 variant pandemic.

Acute transverse myelitis (ATM) associated with COVID 19 infection and vaccination: A case report and literature review

Acute transverse myelitis (ATM) is an inflammatory disorder caused by many etiologies, from postinfectious to autoimmune. Rarely, ATM cases have been reported after both COVID-19 infection and COVID-19 vaccination. We described our experience with ATM after COVID-19 infection and conducted a literature review.

Case finding Methods

We reported a case of longitudinally extensive ATM after COVID 19 infection, who also received convalescent plasma therapy, and present a comprehensive literature review of ATM cases reported after COVID-19 infection and COVID-19 vaccination. The literature search was done using PubMed and Google scholar with keywords and selected peer-reviewed articles. The search included all cases from Jan 2020 to Sept 2022.

Results

A total of 60 ATM cases reported association with post COVID 19 infection, and 23 ATM cases reported association with post COVID 19 vaccinations. Among post COVID 19 ATM cases, the mean age was 49 years and the youngest reported was 7-month-old. A total of 55% (33) were longitudinally extensive ATM. The most common symptom was lower extremity weakness. One case was reported as necrotizing myelitis on biopsy, and another case overlapped with syndrome of GBS and longitudinal ATM. No cases reported using convalescent plasma therapy after infection. Almost all the ATM cases were treated with steroids, but some cases needed additional treatment since not all responded adequately. Six cases (10%) responded with steroids plus plasmapheresis, and 5 cases (8%) responded with steroids + IVIG, especially in the pediatric age group. One case reported a positive response after treatment with eculizumab, and another with infliximab. Two cases (3%) remained paraparetic. Among post covid-19 vaccine ATM cases, 4 cases (17%) were reported as longitudinally extensive ATM. Five cases (21%) had symptom onset within a week after vaccination. Almost all reported a response to steroids except for one case which reported fatality after the 58th day after vaccination.

Conclusion

ATM, in the setting of acute COVID-19 infection, has been described in multiple cases and is a rare complication of COVID-19 vaccination.

Cardiac and Neurological Complications Post COVID-19 Vaccination: A Systematic Review of Case Reports and Case Series

Following mass vaccinations for the control of the COVID-19 epidemic, a spectrum of cardiac and neurological disorders was reported among vaccinated individuals. This study examined the range of complications documented and factors related to their occurrence. Three electronic databases were searched for case reports and case series with descriptions of cardiac and/or neurological complications in COVID-19 vaccine recipients. A total of 698 vaccinees were included in this review, of which 259 (37.1%) had cardiac and 439 (62.9%) had neurological complications. Inflammatory conditions were the commonest among the cardiac complications; while polyneuropathy, demyelinating diseases and cerebrovascular disorders were the more common neurological complications. The mean age of those with cardiac complications (33.8 years) was much younger than those with neurological complications (49.7 years). There was no notable difference in the gender distribution between these two groups of vaccine recipients. mRNA vaccines (all brands) were associated with almost 90.0% of the cardiac complications, whereas viral vector vaccines were associated with slightly over half (52.6%) of the neurological complications. With regard to the dose, cardiac complications were more common after the second (69.1%), whereas neurological complications were more common after the first dose (63.6%). The majority of the cases had an uncomplicated clinical course. Nevertheless, 5.9% of cases with neurological complications and 2.5% of those with cardiac complications were fatal, underscoring the significance of the consistent surveillance and vigilant monitoring of vaccinated individuals to mitigate these occurrences.

A report on neurogenic bladder in COVID-19 vaccine-associated acute transverse myelitis

INTRODUCTION

Acute transverse myelitis (ATM) is a rare neurological complication of Coronavirus disease (COVID-19) vaccines. Various vaccines have been linked to ATM, such as non-replicating viral vectors, ribonucleic acid, and inactivated vaccines. An ATM case is presented here involving the BNT162b2 vaccine leading to asymmetrical incomplete paraplegia and neurogenic bladder.

CASE PRESENTATION

A 66-year-old male developed urinary retention one day after his second dose of the BNT162b2 vaccine, followed by rapidly progressing lower limb weakness. Clinical examination showed asymmetrical paraparesis, reduced sensation below the T8 level, including perianal sensation, and loss of ankle and anal reflexes. Laboratory tests were largely unremarkable, while the spine MRI revealed thickened conus medullaris with a mild increase in T2/STIR signal intensity and subtle enhancement post gadolinium. Following treatment with methylprednisolone, plasmapheresis, and immunoglobulin, and a rehabilitation program, the patient achieved good motor and sensory recovery, but the bladder dysfunction persisted. Single-channel cystometry indicated neurogenic detrusor underactivity and reduced bladder sensation, as evidenced by low-pressure and compliant bladder. The urethral sphincter appeared intact or overactive. The post-void residual urine was significant, necessitating prolonged intermittent catheterisation.

DISCUSSION

Bladder dysfunction due to the COVID-19 vaccine-associated ATM is not as commonly reported as motor or sensory deficits. To our knowledge, this is the first case to highlight a neurogenic bladder that necessitates prolonged intermittent catheterisation as a consequence of COVID-19 vaccine-associated ATM. This report highlights the rare complication of the neurogenic bladder resulting from the BNT162b2 vaccine. Early detection and treatment are crucial to prevent long-term complications.

COVID-19 mortality paradox (United States vs Africa): Mass vaccination vs early treatment

The coronavirus disease 2019 (COVID-19) mortality rate in 55 African countries is almost 4.5 times lower than in the coronavirus disease 2019 (COVID-19) despite Africa having over 4.2 times more people. This mortality paradox is also evident when comparing Nigeria, a heavily populated, poorly vaccinated and weakly mandated country to Israel, a small, highly vaccinated and strictly mandated country. Nigeria has almost 4 times lower COVID mortality than Israel. In this Field of Vision perspective, I explain how this paradox has evolved drawing upon my academic, clinical and social experience. Since April 2020, I've developed and been using the Egyptian immune-modulatory Kelleni's protocol to manage COVID-19 patients including pediatric, geriatric, pregnant, immune-compromised and other individuals suffering from multiple comorbidities. It's unfortunate that severe acute respiratory syndrome coronavirus 2 is still evolving accompanied by more deaths. However in Africa, we've been able to live without anxiety or mandates throughout the pandemic because we trust science and adopted early treatment using safe, and effective repurposed drugs that have saved the majority of COVID-19 patients. This article represents an African and Egyptian tale of honor.

Neurological complications following mRNA COVID-19 vaccination: Oral and lower limb paresthesia. A case discussion and literature review

Vaccines used in the coronavirus pandemic have reported some minor side effects such as pain at the injection site, headache, myalgia and fever. Also major neurological side effects have been experienced by some patients. We present the clinical case of a healthy woman who two weeks after being vaccinated with the third dose of Moderna COVID-19 Vaccine, began to feel numbness in mouth, both feet, legs, interscapular space, and hands. She was diagnosed with distal sensory polyneuropathy caused by the vaccine. Progressive improvement was seen. The patient did not require corticosteroid medication. We reviewed the literature to assess the frequency of this type of complication. Key words:COVID-19, SARS-CoV-2, vaccine, vaccination, peripheral axonal neuropathy, transverse myelitis, oral manifestations.

Association of seizure with COVID-19 vaccines in persons with epilepsy: A systematic review and meta-analysis

Seizure aggravation following coronavirus disease 2019 (COVID-19) vaccines is a major cause behind vaccine hesitancy among persons with epilepsy (PwE), resulting in lower immunization rates. We systematically reviewed seizure-activity-related events in PwE following COVID-19 vaccination. We systematically searched PubMed, Web of Science, Scopus, and Cochrane Library, until January 31, 2023, and included articles reporting seizure activity-related events in PwE receiving COVID-19 vaccination. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses were followed. The protocol was registered with PROSPERO (CRD42022312475). Outcomes included pooled incidence proportions of (a) increased seizure frequency, (b) status epilepticus (SE), and (c) change in seizure type. Of the 2207 studies, 16 entered the meta-analysis. The pooled incidence proportion of increased seizure frequency (16 studies-3245 PwE) was 5% (95% CI: 3%-7%, I2  = 52%). Regarding increased seizure frequency, no significant difference was observed between mRNA and viral vector (OR: 1.11, 95% CI: 0.49-2.52, I2  = 0%), and between mRNA and inactivated virus (OR: 1.60, 95% CI: 0.27-9.37; I2  = 0%). The pooled incidence proportion of SE (15 studies-2387 PwE) was 0.08% (95% CI: 0.02%-0.33%, I2  = 0%). Ultimately, the pooled incidence proportion of change in seizure type (7 studies-1172 PwE) was 1% (95% CI: 1%-2%, I2  = 0%). The meta-analysis revealed post-COVID-19-vaccination increased seizure frequency in 5% of PwE, with no difference between mRNA and viral vector or inactivated virus vaccines. Furthermore, we found 0.08% and 1% incidence proportions for postvaccination SE and change in seizure type, respectively. While noteworthy, these values are far less than reports for COVID-19 infection, emphasizing vaccination importance in preventing COVID-19 consequences in PwE.

Post-COVID-19 Vaccination CNS Magnetic Resonance Imaging Findings: A Systematic Review

Objective

This systematic review aims to synthesize and analyze the available literature on central nervous system (CNS) magnetic resonance imaging (MRI) findings in individuals who have received COVID-19 vaccinations. Our objective is to enhance understanding of potential neurological side effects, inform clinical practice, and guide future research on the neurological implications of COVID-19 vaccination.

Methods

In this systematic review, we conducted a comprehensive search in PubMed, Scopus, and Web of Science from January 2020 to April 2023, using terms related to COVID-19 vaccination and CNS MRI findings. We evaluated the quality of the study, extracted relevant data, and included 89 eligible studies that covered various vaccines, demographics of patients, symptoms, and MRI findings to provide a thorough understanding of SARS-CoV-2 vaccination-related CNS problems.

Results

We investigated CNS MRI findings following COVID-19 vaccination across various vaccine types. Common diseases associated with post-vaccination CNS MRI findings included cerebral venous sinus thrombosis (CVST), vaccine-induced immune thrombotic thrombocytopenia (VITT), acute disseminated encephalomyelitis (ADEM), acute myelitis, autoimmune encephalitis (AE), and others. Patients presented with diverse onset symptoms and neurological manifestations. Abnormalities identified in CNS MRI findings included white matter (WM) hyperintensity. Our analysis offers a comprehensive overview of the current literature on post-vaccination CNS MRI findings. Discussion. We highlight a range of post-COVID-19 vaccination CNS MRI findings, including CVST, with a higher incidence in individuals receiving the ChAdOx1 (AstraZeneca) vaccine. Other notable observations include cases of ADEM, myelitis or transverse myelitis (TM), Guillain-Barré syndrome (GBS), and acute encephalopathy following COVID-19 vaccination. The incidence of these neurological complications is extremely rare, and the benefits of vaccination outweigh the risks. The reviewed studies were primarily case reports or case series, and thus large-scale epidemiological studies and controlled clinical trials are needed to better understand the underlying mechanisms and risk factors associated with these neurological complications following COVID-19 vaccination.

Association of SARS-CoV-2 Vaccination or Infection With Bell Palsy: A Systematic Review and Meta-analysis

Importance

Bell palsy (BP) has been reported as an adverse event following the SARS-CoV-2 vaccination, but neither a causative relationship nor a higher prevalence than in the general population has been established.

Objective

To compare the incidence of BP in SARS-CoV-2 vaccine recipients vs unvaccinated individuals or placebo recipients.

Data Sources

A systematic search of MEDLINE (via PubMed), Web of Science, Scopus, Cochrane Library, and Google Scholar from the inception of the COVID-19 report (December 2019) to August 15, 2022.

Study Selection

Articles reporting BP incidence with SARS-CoV-2 vaccination were included.

Data Extraction and Synthesis

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and was conducted with the random- and fixed-effect models using the Mantel-Haenszel method. The quality of the studies was evaluated by the Newcastle-Ottawa Scale.

Main Outcomes and Measures

The outcomes of interest were to compare BP incidence among (1) SARS-CoV-2 vaccine recipients, (2) nonrecipients in the placebo or unvaccinated cohorts, (3) different types of SARS-CoV-2 vaccines, and (4) SARS-CoV-2-infected vs SARS-CoV-2-vaccinated individuals.

Results

Fifty studies were included, of which 17 entered the quantitative synthesis. Pooling 4 phase 3 randomized clinical trials showed significantly higher BP in recipients of SARS-CoV-2 vaccines (77 525 vaccine recipients vs 66 682 placebo recipients; odds ratio [OR], 3.00; 95% CI, 1.10-8.18; I2 = 0%). There was, however, no significant increase in BP after administration of the messenger RNA SARS-CoV-2 vaccine in pooling 8 observational studies (13 518 026 doses vs 13 510 701 unvaccinated; OR, 0.70; 95% CI, 0.42-1.16; I2 = 94%). No significant difference was found in BP among 22 978 880 first-dose recipients of the Pfizer/BioNTech vaccine compared with 22 978 880 first-dose recipients of the Oxford/AstraZeneca vaccine (OR, 0.97; 95% CI, 0.82-1.15; I2 = 0%). Bell palsy was significantly more common after SARS-CoV-2 infection (n = 2 822 072) than after SARS-CoV-2 vaccinations (n = 37 912 410) (relative risk, 3.23; 95% CI, 1.57-6.62; I2 = 95%).

Conclusions and Relevance

This systematic review and meta-analysis suggests a higher incidence of BP among SARS-CoV-2-vaccinated vs placebo groups. The occurrence of BP did not differ significantly between recipients of the Pfizer/BioNTech vs Oxford/AstraZeneca vaccines. SARS-CoV-2 infection posed a significantly greater risk for BP than SARS-CoV-2 vaccination.

Onset of Guillain-Barre Syndrome and Transverse Myelitis Following COVID-19 Vaccination

Guillain-Barre syndrome (GBS) and transverse myelitis (TM) are both neuro-inflammatory disorders that are attributed to dysfunctions of the peripheral nervous system and spinal cord, respectively. The two conditions involve immune-mediated destruction and inflammation of the nervous system and may present clinically as a weakness in the muscles, loss of normal sensations, and even paralysis of the body or extremities. Although the incidence of GBS and TM is quite rare, there have been reports of the two diseases developing in patients, either independently or concurrently, following COVID-19 vaccinations. In this case report, we present a patient (male) who lost functions and sensations in his lower extremities 60 days after he received the COVID-19 booster vaccine. The patient's blood work was unremarkable. Magnetic resonance imaging (MRI) of his thoracic spine and an electromyography study revealed evidence of nerve demyelination, which supports the diagnosis of GBS/TM overlap syndrome. He was ultimately treated with intravenous immunoglobulins (IVIGs) and gained back functions in his lower extremities.

Neurological Considerations with COVID-19 Vaccinations

The benefits of coronavirus disease 2019 (COVID-19) vaccination significantly outweigh its risks on a public health scale, and vaccination has been crucial in controlling the spread of SARS-CoV-2. Nonetheless, several reports of adverse events following vaccination have been published.To summarize reports to date and assess the extent and quality of evidence regarding possible serious adverse neurological events following COVID-19 vaccination, focusing on Food and Drug Administration (FDA)-approved vaccines in the United States (BNT162b2, mRNA-1273, and Ad26.COV2.S).A review of literature from five major electronic databases (PubMed, Medline, Embase, Cochrane Library, and Google Scholar) was conducted between December 1, 2020 and June 5, 2022. Articles included in the review were systematic reviews and meta-analysis, cohort studies, retrospective studies, case-control studies, case series, and reports. Editorials, letters, and animal studies were excluded, since these studies did not include quantitative data regarding adverse side effects of vaccination in human subjects.Of 149 total articles and 97 (65%) were case reports or case series. Three phase 3 trials initially conducted for BNT162b2, MRNA-1273, and Ad26.COV2.S were included in the analysis.The amount and quality of evidence for possible neurological adverse events in the context of FDA-approved COVID-19 vaccinations is overall low tier. The current body of evidence continues to suggest that COVID-19 vaccinations have a high neurological safety profile; however, the risks and benefits of vaccination must continue to be closely monitored.

Can COVID-19 Vaccines Induce Premature Non-Communicable Diseases: Where Are We Heading to?

According to the WHO, as of January 2023, more than 850 million cases and over 6.6 million deaths from COVID-19 have been reported worldwide. Currently, the death rate has been reduced due to the decreased pathogenicity of new SARS-CoV-2 variants, but the major factor in the reduced death rates is the administration of more than 12.8 billion vaccine doses globally. While the COVID-19 vaccines are saving lives, serious side effects have been reported after vaccinations for several premature non-communicable diseases (NCDs). However, the reported adverse events are low in number. The scientific community must investigate the entire spectrum of COVID-19-vaccine-induced complications so that necessary safety measures can be taken, and current vaccines can be re-engineered to avoid or minimize their side effects. We describe in depth severe adverse events for premature metabolic, mental, and neurological disorders; cardiovascular, renal, and autoimmune diseases, and reproductive health issues detected after COVID-19 vaccinations and whether these are causal or incidental. In any case, it has become clear that the benefits of vaccinations outweigh the risks by a large margin. However, pre-existing conditions in vaccinated individuals need to be taken into account in the prevention and treatment of adverse events.

Onset of various CNS inflammatory demyelination diseases following COVID-19 vaccinations

BACKGROUND

Since the start of COVID-19 vaccination worldwide, there have been several reports of inflammatory demyelinating diseases of the central nervous system (CNS-IDDs) following vaccination.

METHODS

We prospectively collected cases of new-onset CNS-IDDs with a temporal relationship between disease onset and COVID-19 vaccination and investigated their proportion among newly registered cases of CNS-IDD over the past year.

RESULTS

Among 117 cases, 10 (8.5%) had their first disease manifestation within one month following COVID-19 vaccination: 2 multiple sclerosis, 2 neuromyelitis optica spectrum disorder, 3 MOG antibody-associated disease, and 3 unclassified CNS-IDDs.

CONCLUSION

This observation suggests that COVID-19 vaccination may trigger the onset of various CNS-IDDs in susceptible individuals.

COVID-19 vaccine associated transverse myelitis-Evusheld as an option when vaccination is not recommended due to severe adverse events

Individuals who experience severe COVID-19-vaccine-related adverse reactions such as transverse myelitis may be precluded from receiving further vaccination to protect from SARS-CoV-2 infection. Although the mechanism of autoimmune spinal cord inflammation resulting in transverse myelitis is unclear, it may be safe to administer antibody therapy for preventing COVID-19. Recently, Evusheld, tixagevimab with cilgavimab, two spike-protein directed monoclonal antibodies were authorized by the U.S. FDA and U.K. MHRA for administration to individuals when vaccination is not recommended. We report the safe administration of Evusheld to a patient who experienced transverse myelitis 11 months previously as a result of receiving the Moderna mRNA vaccine. This patient has experienced no adverse events to Evusheld. Additional experience and data collection are warranted to determine the safety of this prophylactic therapy.

Clinical characteristics, radiological features and prognostic factors of transverse myelitis following COVID-19 vaccination: A systematic review

BACKGROUND

Since introducing COVID-19 vaccines, many neurological complications such as acute transverse myelitis have been reported in the literature. This study aims to identify the clinical characteristics, radiological findings, and prognostic factors in patients with COVID-19 vaccine-associated transverse myelitis (TM).

METHODS

We systematically reviewed Scopus, Pubmed, Cochrane library, Google Scholar, and preprint databases using appropriate keywords from inception till 8th April 2022. Besides, we manually searched the reference lists of the included studies and relevant previous reviews.

RESULTS

We included 28 studies identifying 31 post-COVID-19 vaccination myelitis patients (17 female and 14 male). The mean age of the included patients was 52±19 years. ChAdOx1 nCoV-19 vaccine (Oxford-AstraZeneca) was the most common type of vaccine in association with myelitis (12 out of 31), followed by Pfizer (8 out of 31), Moderna (7 out of 31), Sinopharm (3 out of 31), and Janssen vaccine (1 out of 31). The myelitis occurred in 24 and 7 patients after administering the first and second dose of the vaccine, respectively. 21 and 10 patients had good recovery (Modified Rankin Score (MRS) <3 at the follow-up) and poor recovery (MRS≥3 at the follow-up) from myelitis, respectively. Age (OR 1.09, 95%CI 1.01-1.18, pvalue 0.02), and MRS at admission (OR 17.67, 95%CI 1.46-213.76, pvalue 0.024) were two independent risk factors for poor recovery from myelitis.

CONCLUSION

The patients with higher age and MRS at admission had a worse prognosis and needed timely and more aggressive therapeutic strategies.

Autoimmune and autoinflammatory conditions after COVID-19 vaccination. New case reports and updated literature review

Autoimmunity linked to COVID-19 immunization has been recorded throughout the pandemic. Herein we present six new patients who experienced relapses of previous autoimmune disease (AD) or developed a new autoimmune or autoinflammatory condition following vaccination. In addition, we documented additional cases through a systematic review of the literature up to August 1st, 2022, in which 464 studies (928 cases) were included. The majority of patients (53.6%) were women, with a median age of 48 years (IQR: 34 to 66). The median period between immunization and the start of symptoms was eight days (IQR: 3 to 14). New-onset conditions were observed in 81.5% (n: 756) of the cases. The most common diseases associated with new-onset events following vaccination were immune thrombocytopenia, myocarditis, and Guillain-Barré syndrome. In contrast, immune thrombocytopenia, psoriasis, IgA nephropathy, and systemic lupus erythematosus were the most common illnesses associated with relapsing episodes (18.5%, n: 172). The first dosage was linked with new-onset events (69.8% vs. 59.3%, P = 0.0100), whereas the second dose was related to relapsing disease (29.5% vs. 59.3%, P = 0.0159). New-onset conditions and relapsing diseases were more common in women (51.5% and 62.9%, respectively; P = 0.0081). The groups were evenly balanced in age. No deaths were recorded after the disease relapsed, while 4.7% of patients with new-onset conditions died (P = 0.0013). In conclusion, there may be an association between COVID-19 vaccination and autoimmune and inflammatory diseases. Some ADs seem to be more common than others. Vaccines and SARS-CoV-2 may induce autoimmunity through similar mechanisms. Large, well-controlled studies are warranted to validate this relationship and assess additional variables such as genetic and other environmental factors.

A Rare Case of Longitudinally Extensive Transverse Myelitis Following Pfizer-BioNTech COVID-19 Vaccination with a Favourable Outcome

Introduction

mRNA COVID-19 vaccines are very safe, but rare adverse events such as transverse myelitis have been reported after COVID-19 vaccination.

Case Description

We report the case of 50-year-old man who presented with progressive lower extremity weakness, back pain and urinary retention after his second dose of the Pfizer COVID-19 vaccine. MRI of the spine revealed longitudinally extensive transverse myelitis (LETM). He recovered completely after treatment with intravenous methylprednisone and physical therapy.

Discussion

This case highlights the rare association between LETM and COVID-19 vaccines and encourages clinicians to maintain a high index of suspicion for prompt diagnosis and treatment.

LEARNING POINTS

Longitudinally extensive transverse myelitis (LETM) is rare adverse events after mRNA COVID-19 vaccination.Clinicians should maintain a high index of suspicion for prompt diagnosis of vaccine-induced transverse myelitis.Vaccine-induced LETM should show marked clinical improvement after appropriate treatment.

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.

Rare Heterogeneous Adverse Events Associated with mRNA-Based COVID-19 Vaccines: A Systematic Review

Background: Since the successful development, approval, and administration of vaccines against SARS-CoV-2, the causative agent of COVID-19, there have been reports in the published literature, passive surveillance systems, and other pharmacovigilance platforms of a broad spectrum of adverse events following COVID-19 vaccination. A comprehensive review of the more serious adverse events associated with the Pfizer-BioNTech and Moderna mRNA vaccines is warranted, given the massive number of vaccine doses administered worldwide and the novel mechanism of action of these mRNA vaccines in the healthcare industry. Methods: A systematic review of the literature was conducted to identify relevant studies that have reported mRNA COVID-19 vaccine-related adverse events. Results: Serious and severe adverse events following mRNA COVID-19 vaccinations are rare. While a definitive causal relationship was not established in most cases, important adverse events associated with post-vaccination included rare and non-fatal myocarditis and pericarditis in younger vaccine recipients, thrombocytopenia, neurological effects such as seizures and orofacial events, skin reactions, and allergic hypersensitivities. Conclusions: As a relatively new set of vaccines already administered to billions of people, COVID-19 mRNA-based vaccines are generally safe and efficacious. Further studies on long-term adverse events and other unpredictable reactions in close proximity to mRNA vaccination are required.