Association between Guillain-Barré syndrome and influenza A (H1N1) 2009 monovalent inactivated vaccines in the USA: a meta-analysis

Expanding our understanding of Guillain-Barré syndrome: Recent advances and clinical implications

Guillain-Barré syndrome (GBS) is a rare yet potentially life-threatening disorder of the peripheral nervous system (PNS), characterized by substantial clinical heterogeneity. Although classified as an autoimmune disease, the immune mechanisms underpinning distinct GBS subtypes remain largely elusive. Traditionally considered primarily antibody-mediated, the pathophysiology of GBS lacks clarity, posing challenges in the development of targeted and effective treatments. Nevertheless, recent investigations have substantially expanded our understanding of the disease, revealing an involvement of autoreactive T cell immunity in a major subtype of GBS patients and opening new biomedical perspectives. This review highlights these discoveries and offers a comprehensive overview of current knowledge about GBS, including ongoing challenges in disease management.

Guillain-Barré syndrome: a comprehensive review

Guillain-Barré syndrome (GBS) is a potentially devastating yet treatable disorder. A classically postinfectious, immune-mediated, monophasic polyradiculoneuropathy, it is the leading global cause of acquired neuromuscular paralysis. In most cases, the immunopathological process driving nerve injury is ill-defined. Diagnosis of GBS relies on clinical features, supported by laboratory findings and electrophysiology. Although previously divided into primary demyelinating or axonal variants, this dichotomy is increasingly challenged, and is not endorsed by the recent European Academy of Neurology (EAN)/Peripheral Nerve Society (PNS) guidelines. Intravenous immunoglobulin and plasma exchange remain the primary modalities of treatment, regardless of the electrophysiological subtype. Most patients recover, but approximately one-third require mechanical ventilation, and 5% die. Disease activity and treatment response are currently monitored through interval neurological examination and outcome measures, and the potential role of fluid biomarkers is under ongoing scrutiny. Novel potential therapies for GBS are being explored but none have yet modified clinical practice. This review provides a comprehensive update on the pathological and clinical aspects of GBS for clinicians and scientists.

Guillain-Barre syndrome and link with COVID-19 infection and vaccination: a review of literature

Background

Guillain-Barré syndrome (GBS) is an autoimmune disease associated with significant morbidity. A wide variety of infectious and non-infectious triggers have been identified to be associated with GBS. COVID-19 has gained attention in recent years for its role in GBS pathogenesis. Our study aims to review the literature on GBS and its epidemiological and pathophysiological association with COVID-19.

Description

Recent literature on GBS associated with COVID-19 infections, such as case reports, case series, systematic reviews, and large-scale epidemiological studies, were reviewed. We also reviewed studies that included vaccines against COVID-19 in association with GBS. Studies that focused on understanding the pathobiology of GBS and its association with infectious agents including COVID-19 were reviewed.

Conclusion

Despite a lack of consensus, GBS is strongly associated with COVID-19 infection. The exact pathophysiological mechanism regarding COVID-19 as a causative agent of GBS is unknown. Mechanisms, such as the proinflammatory state, triggering of autoimmunity, and direct viral invasion, are postulated and remain to be investigated. Adenovirus vector vaccines are most likely associated with GBS, and the consensual reports clearly suggest mRNA vaccines are associated with low risk and may be protective against GBS by reducing the risk of COVID-19 infection.

Experience of treatment in critical Guillain-Barre Syndrome case after COVID-19 vaccination

BACKGROUND

The current study reported a case with a history of neuroradiculitis. Within 2 months of the COVID-19 vaccine, critical Guillain-Barre Syndrome (GBS) appeared after acute diarrhea, progressive myasthenia, and sudden respiratory and cardiac symptoms.

METHODS

The syndrome was addressed with measures, such as endotracheal intubation and cardiopulmonary resuscitation vasoactive drugs. Next, we conducted six cycles of human immunoglobulin treatment (dose of 400 mg/kg·d intravenously for 5 days consecutively) and three times plasma exchange (PE, 30 ml/kg), followed by methylprednisolone sodium succinate. Rehabilitation training was carried out continuously.

RESULTS

The consciousness of the patient returned to normal, wherein he carried out normal communication. The muscle strength recovered gradually but still could not stand independently. Presently, he is recovering at home.

CONCLUSIONS

For patients with previous radiculitis, COVID-19 vaccination may increase the susceptibility to GBS. Thus, it is recommended to extend the vaccination interval for these patients and ensure that any potential increased risk is continually assessed.

Vaccines and the Eye: Current Understanding of the Molecular and Immunological Effects of Vaccination on the Eye

Vaccination is a public health cornerstone that protects against numerous infectious diseases. Despite its benefits, immunization implications on ocular health warrant thorough investigation, particularly in the context of vaccine-induced ocular inflammation. This review aimed to elucidate the complex interplay between vaccination and the eye, focusing on the molecular and immunological pathways implicated in vaccine-associated ocular adverse effects. Through an in-depth analysis of recent advancements and the existing literature, we explored various mechanisms of vaccine-induced ocular inflammation, such as direct infection by live attenuated vaccines, immune complex formation, adjuvant-induced autoimmunity, molecular mimicry, hypersensitivity reactions, PEG-induced allergic reactions, Type 1 IFN activation, free extracellular RNA, and specific components. We further examined the specific ocular conditions associated with vaccination, such as uveitis, optic neuritis, and retinitis, and discussed the potential impact of novel vaccines, including those against SARS-CoV-2. This review sheds light on the intricate relationships between vaccination, the immune system, and ocular tissues, offering insights into informed discussions and future research directions aimed at optimizing vaccine safety and ophthalmological care. Our analysis underscores the importance of vigilance and further research to understand and mitigate the ocular side effects of vaccines, thereby ensuring the continued success of vaccination programs, while preserving ocular health.

An updated review on Guillain-Barré syndrome: Challenges in infection prevention and control in low- and middle-income countries

Guillain-Barré syndrome is a rare condition that can be potentially life-threatening. Guillain-Barré syndrome does not have a definitive etiological agent. It is a syndrome that can arise from multiple factors, including various infectious diseases and immunizations. The severity of Guillain-Barré syndrome is exacerbated by these variables, especially in low-income and middle-income countries where healthcare systems are already constrained and struggle to meet the demands of other diseases. The primary aim of our article is to comprehensively examine the life-threatening nature and intensity of Guillain-Barré syndrome by assessing its etiology, progression, and prevalence in low- and middle-income nations while also considering global trends. Furthermore, we proposed the implementation of standard and efficacious treatment and diagnostic resources that are readily accessible and successful in affluent nations and should also be readily accessible in impoverished nations without any unnecessary delay. Our study also emphasized the epidemiological data with molecular epidemiological analysis and the utilization of artificial technology in low- and middle-income nations. The goal was to decrease the incidence of Guillain-Barré syndrome cases and facilitate early detection.

Guillain-Barré syndrome and COVID-19 vaccination: a systematic review and meta-analysis

BACKGROUND

Case-reports/series and cohorts of Guillain-Barré syndrome (GBS) associated with COVID-19 vaccination have been reported.

METHODS

A systematic review and meta-analysis of cohort studies of GBS after COVID-19 vaccination was carried out. Incidence and incidence rate ratio for a number of vaccine doses and risk of GBS, also considering the specific vaccine technology, were calculated in a random-effects model.

RESULTS

Of 554 citations retrieved, 518 were discarded as irrelevant. We finally included 15 studies. The random effect model yielded, regardless of the vaccine technology, 1.25 (95%CI 0.21; 2.83) GBS cases per million of COVID-19 vaccine doses, 3.93 (2.54; 5.54) cases per million doses for adenovirus-vectored vaccines and 0.69 (0.38; 1.06) cases per million doses for mRNA vaccines. The GBS risk was 2.6 times increased with the first dose. Regardless of the vaccine technology, the GBS risk was not increased but disaggregating the data it was 2.37 (1.67; 3.36) times increased for adenovirus-vectored vaccines and 0.32 (0.23; 0.47) for mRNA vaccines. Mortality for GBS after vaccination was 0.10 per million doses and 4.6 per GBS cases.

CONCLUSIONS

Adenovirus-vectored vaccines showed a 2.4 times increased risk of GBS that was about seven times higher compared with mRNA-based vaccines. The decreased GBS risk associated with mRNA vaccines was possibly due to an elicited reduction of infections, including SARS-CoV-2, associated with GBS during the vaccination period. How adenovirus-vectored COVID-19 vaccines may trigger GBS is unclear and further studies should investigate the relationship between vaccine technologies and GBS risk.

Lessons learned from COVID-19, H1N1, and routine vaccine pharmacovigilance in the United States: a path to a more robust vaccine safety program

INTRODUCTION

Vaccine pharmacovigilance is an essential component of vaccine safety programs. Vaccine pharmacovigilance refers to detecting uncommon adverse events following immunization (AEFI), determining whether they are due to the vaccine or are only a coincidence, and, for those AEFI considered related to vaccination, characterizing them further. When AEFI are due to vaccination, it is important to characterize the attributable risk and ascertain the biological mechanism causing the adverse reaction to inform efforts to prevent or mitigate the risk. A robust post-authorization safety system is necessary for vaccine decision-making, clinical recommendations, vaccine compensation, and vaccine communication and confidence.

AREAS COVERED

This paper describes the key characteristics of vaccine pharmacovigilance programs, reviews US vaccine pharmacovigilance for routine vaccination programs, COVID-19, and H1N1, and makes recommendations for improving future vaccine safety systems.

EXPERT OPINION

The key characteristics of vaccine pharmacovigilance programs include passive surveillance, active surveillance, clinical investigation and special studies, and causality assessment. Recent examples illustrate the strengths of US pharmacovigilance systems, including systems for passive and active surveillance, as well as areas for improvement, including study of pathogenesis, consistent funding, and leadership. We make recommendations that would, if implemented, further strengthen the vaccine safety system for future routine and pandemic immunizations.

Bayesian safety surveillance with adaptive bias correction

Postmarket safety surveillance is an integral part of mass vaccination programs. Typically relying on sequential analysis of real-world health data as they accrue, safety surveillance is challenged by sequential multiple testing and by biases induced by residual confounding in observational data. The current standard approach based on the maximized sequential probability ratio test (MaxSPRT) fails to satisfactorily address these practical challenges and it remains a rigid framework that requires prespecification of the surveillance schedule. We develop an alternative Bayesian surveillance procedure that addresses both aforementioned challenges using a more flexible framework. To mitigate bias, we jointly analyze a large set of negative control outcomes that are adverse events with no known association with the vaccines in order to inform an empirical bias distribution, which we then incorporate into estimating the effect of vaccine exposure on the adverse event of interest through a Bayesian hierarchical model. To address multiple testing and improve on flexibility, at each analysis timepoint, we update a posterior probability in favor of the alternative hypothesis that vaccination induces higher risks of adverse events, and then use it for sequential detection of safety signals. Through an empirical evaluation using six US observational healthcare databases covering more than 360 million patients, we benchmark the proposed procedure against MaxSPRT on testing errors and estimation accuracy, under two epidemiological designs, the historical comparator and the self-controlled case series. We demonstrate that our procedure substantially reduces Type 1 error rates, maintains high statistical power and fast signal detection, and provides considerably more accurate estimation than MaxSPRT. Given the extensiveness of the empirical study which yields more than 7 million sets of results, we present all results in a public R ShinyApp. As an effort to promote open science, we provide full implementation of our method in the open-source R package EvidenceSynthesis.

Non-mutational neoantigens in disease

The ability of mammals to mount adaptive immune responses culminating with the establishment of immunological memory is predicated on the ability of the mature T cell repertoire to recognize antigenic peptides presented by syngeneic MHC class I and II molecules. Although it is widely believed that mature T cells are highly skewed towards the recognition of antigenic peptides originating from genetically diverse (for example, foreign or mutated) protein-coding regions, preclinical and clinical data rather demonstrate that novel antigenic determinants efficiently recognized by mature T cells can emerge from a variety of non-mutational mechanisms. In this Review, we describe various mechanisms that underlie the formation of bona fide non-mutational neoantigens, such as epitope mimicry, upregulation of cryptic epitopes, usage of non-canonical initiation codons, alternative RNA splicing, and defective ribosomal RNA processing, as well as both enzymatic and non-enzymatic post-translational protein modifications. Moreover, we discuss the implications of the immune recognition of non-mutational neoantigens for human disease.

Statistics of Rare Events

Rare events can sometime arise in clinical development of treatments. For example, CYPIDES was a single-arm study of the CYP11A1 inhibitor ODM-208 to treat metastatic prostate cancer.1 Preclinical testing of the compound identified elevated thyroid-stimulating hormone (TSH) and bilirubin in rats and dogs. Unusual findings in preclinical testing focus attention and magnify evidence if similar results occur in humans. By analogy, imagine a murder trial in which the only evidence against the defendant arose from a database search of DNA matching the partial profile found at the crime scene. Multiple people could match, so without other evidence, the perpetrator could be any of them.

Current status of Guillain-Barré syndrome (GBS) in China: a 10-year comprehensive overview

Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy; a disease involving the peripheral nervous system which is the most common cause of acute flaccid paralysis worldwide. So far, it is still lack of a comprehensive overview and understanding of the national epidemiological, clinical characteristics, and the risk factors of GBS in China, as well as differences between China and other countries and regions in these respects. With the global outbreak of the coronavirus disease 2019 (COVID-19), an epidemiological or phenotypic association between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and GBS has attracted great attention. In this review, we outlined the current clinical data of GBS in China by retrieving literature, extracting and synthesizing the data of GBS in China from 2010 to 2021. Besides, we compared the characteristics of epidemiology, preceding events and clinical profiles of GBS between China and other countries and regions. Furthermore, in addition to conventional intravenous immunoglobulin (IVIG) and plasma exchange (PE) therapy, the potential therapeutic effects with novel medications in GBS, such as complement inhibitors, etc., have become the research focus in treatments. We found that epidemiological and clinical findings of GBS in China are approximately consistent with those in the International GBS Outcome Study (IGOS) cohort. We provided an overall picture of the present clinical status of GBS in China and summarized the global research progress of GBS, aiming to further understand the characteristics of GBS and improve the future work of GBS worldwide, especially in countries with the middle and low incomes.

Incidence of Guillain-Barré syndrome in the world between 1985 and 2020: A systematic review

Introduction

Guillain-Barré syndrome (GBS) is an acute inflammatory demyelinating polyradiculoneuropathy that affects the peripheral nervous system. The study aimed to describe the incidence of GBS in the world up to the year 2020.

Methods

A systematic review was conducted. Searches were done in four databases, PUBMED, EMBASE, EBSCO and Biblioteca virtual em Saude (BVS), and in grey literature and manual search in the reference lists of eligible studies.

Results

A total of 72 studies were included. The incidence of GBS among the cohort studies varied from 0.30 to 6.08 cases per 100.000 habitants and 0.42 to 6.58 cases per 100.000 person-years. Among the self-controlled studies, the risk incidence ranged from 0.072 to 1 case per 100.000 habitants and 1.73 to 4.30 cases per 100.000 person-years.

Conclusions

The reported incidence of GBS in the world among the studies included in the review is slightly higher than that reported in previous studies. The highest incidence rates were associated with public health events of international concern.

Association Between Guillain-Barré Syndrome and COVID-19 Infection and Vaccination: A Population-Based Nested Case-Control Study

BACKGROUND AND OBJECTIVES

Existing data regarding occurrence of Guillain-Barré syndrome (GBS) after coronavirus disease 2019 (COVID-19) infection and vaccination are inconclusive. We aimed to assess the association between GBS and both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 vaccine.

METHODS

We conducted a nested case-control study in a cohort of 3,193,951 patients aged 16 years or older, without a diagnosis of prior GBS, from the largest health care provider in Israel. Participants were followed from January 1, 2021, until June 30, 2022, for the occurrence of GBS. Ten randomly selected controls were matched to each case of GBS on age and sex. We assessed both SARS-CoV-2 infection and COVID-19 vaccine administration in the prior 6 weeks in cases and controls.

RESULTS

Overall, 76 patients were diagnosed with GBS during follow-up and were matched to 760 controls. A positive test for SARS-CoV-2 was detected in 9 (11.8%) cases and 18 (2.4%) controls. An administration of COVID-19 vaccine was detected in 8 (10.5%) cases (all Pfizer-BioNTech [BNT162b2] vaccine) and 136 (17.9%) controls (134 Pfizer-BioNTech vaccine). Multivariable conditional logistic regression models showed that the odds ratio for GBS associated with SARS-CoV-2 infection and COVID-19 vaccine administration was 6.30 (95% CI 2.55-15.56) and 0.41 (95% CI 0.17-0.96), respectively. The results were similar when exposure to SARS-CoV-2 infection or COVID-19 vaccine administration was ascertained in the prior 4 and 8 weeks, although did not reach statistical significance for COVID-19 vaccine at 4 weeks.

DISCUSSION

Our study suggests that SARS-CoV-2 infection is associated with increased risk of GBS, whereas Pfizer-BioNTech COVID-19 vaccine is associated with decreased risk of GBS.

Guillain-Barré Syndrome Following the Administration of Adenovirus Vector-Based COVID-19 Vaccine

As countries worldwide deployed their respective coronavirus disease 2019 (COVID-19) vaccination programs to mitigate the risk of COVID-19 to their citizens, several side effects and complications from the use of the various types of COVID-19 vaccines were documented and are continued to be monitored to further study the safety and efficacy of these vaccines. One such complication, the Guillain-Barré syndrome (GBS), was reported in some individuals who received a COVID-19 adenovirus vector-based vaccine. In this particular report, we describe one such case. The patient had diarrhea and fever one day after vaccination, which was a triggering event. Seven days post vaccination, the patient had bilateral symmetrical weakness with absent deep tendon reflexes. However, causality between the vaccine administered and the suspected adverse reaction cannot be readily assumed. The benefits and risk profiles of each available vaccine should be assessed continuously for it to be improved and truly useful in this pandemic. Thorough post-vaccination surveillance, along with national reporting mechanisms are needed to help establish and confirm possible links between GBS and adenovirus vector-based COVID-19 vaccines. This link needs to be probed further in prospective studies and clinical trials.

Historical Perspectives on the Neurologic Manifestations of Viral Pandemics

Neurologic symptoms have been reported in over 30% of hospitalized patients with coronavirus disease 2019 (COVID-19), but the pathogenesis of these symptoms remains under investigation. Here, we place the neurologic complications of COVID-19 within the context of three historical viral pandemics that have been associated with neurologic diseases: (1) the 1918 influenza pandemic, subsequent spread of encephalitis lethargica, and lessons for the study of COVID-19-related neuroinflammation; (2) the controversial link between the 1976 influenza vaccination campaign and Guillain-Barré Syndrome and its implications for the post- and parainfectious complications of COVID-19 and COVID-19 vaccination; and (3) potential applications of scientific techniques developed in the wake of the human immunodeficiency virus pandemic to the study of postacute sequelae of COVID-19.

Ophthalmoplegia associated with anti-GQ1b antibodies: case report and review

A 60-year-old man with longstanding bilateral asymmetrical ptosis presented with a partial third nerve palsy. His diplopia improved following an ice pack test. He did not report any symptoms related to the coronavirus disease 2019 (COVID-19), and nasopharyngeal swab was negative. Initial head imaging and blood work-up were normal except for a high titer of anti-GQ1b antibodies. The patient was subsequently diagnosed with acute ophthalmoparesis without ataxia which is part of the anti-GQ1b antibody syndrome spectrum. He made a spontaneous recovery over the following months without the need for immunotherapy. Clinical features, pathophysiology and a review of the literature are discussed herein. It is important to consider anti-GQ1b antibody syndrome in patients with symptoms of diplopia, ptosis or suspected ocular myasthenia.

Real-world data on the incidence and risk of Guillain-Barré syndrome following SARS-CoV-2 vaccination: a prospective surveillance study

Increasing evidence suggests an association between SARS-CoV-2 vaccines and Guillain-Barré syndrome (GBS). Nevertheless, little is understood about the contributing risk factors and clinical characteristics of GBS post SARS-CoV-2 vaccination. In this prospective surveillance study of 38,828,691 SARS-CoV-2 vaccine doses administered from February 2021 to March 2022 in the Gyeonggi Province, South Korea, 55 cases of GBS were reported post vaccination. We estimated the incidence rate of GBS per million doses and the incidence rate ratio for the vaccine dose, mechanism, age, and sex. Additionally, we compared the clinical characteristics of GBS following mRNA-based and viral vector-based vaccinations. The overall incidence of GBS following SARS-CoV-2 vaccination was 1.42 per million doses. Viral vector-based vaccines were associated with a higher risk of GBS. Men were more likely to develop GBS than women. The third dose of vaccine was associated with a lower risk of developing GBS. Classic sensorimotor and pure motor subtypes were the predominant clinical subtypes, and demyelinating type was the predominant electrodiagnostic subtype. The initial dose of viral-vector based vaccine and later doses of mRNA-based vaccine were associated with GBS, respectively. GBS following SARS-CoV-2 vaccination may not be clinically distinct. However, physicians should pay close attention to the classic presentation of GBS in men receiving an initial dose of viral vector-based SARS-CoV-2 vaccines.

Reports of Guillain-Barré Syndrome After COVID-19 Vaccination in the United States

IMPORTANCE

Because of historical associations between vaccines and Guillain-Barré syndrome (GBS), the condition was a prespecified adverse event of special interest for COVID-19 vaccine monitoring.

OBJECTIVE

To evaluate GBS reports to the Vaccine Adverse Event Reporting System (VAERS) and compare reporting patterns within 21 and 42 days after vaccination with Ad26.COV2.S (Janssen), BNT162b2 (Pfizer-BioNTech), and mRNA-1273 (Moderna) COVID-19 vaccines.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was conducted using US VAERS reports submitted during December 2020 to January 2022. GBS case reports verified as meeting the Brighton Collaboration case definition for GBS in US adults after COVID-19 vaccination were included.

EXPOSURES

Receipt of the Ad26.COV2.S, BNT162b2, or mRNA-1273 COVID-19 vaccine.

MAIN OUTCOMES AND MEASURES

Descriptive analyses of GBS case were conducted. GBS reporting rates within 21 and 42 days after Ad26.COV2.S, BNT162b2, or mRNA-1273 vaccination based on doses administered were calculated. Reporting rate ratios (RRRs) after receipt of Ad26.COV2.S vs BNT162b2 or mRNA-1273 within 21- and 42-day postvaccination intervals were calculated. Observed-to-expected (OE) ratios were estimated using published GBS background rates.

RESULTS

Among 487 651 785 COVID-19 vaccine doses, 17 944 515 doses (3.7%) were Ad26.COV2.S, 266 859 784 doses (54.7%) were BNT162b2, and 202 847 486 doses (41.6%) were mRNA-1273. Of 295 verified reports of individuals with GBS identified after COVID-19 vaccination (12 Asian [4.1%], 18 Black [6.1%], and 193 White [65.4%]; 17 Hispanic [5.8%]; 169 males [57.3%]; median [IQR] age, 59.0 [46.0-68.0] years), 275 reports (93.2%) documented hospitalization. There were 209 and 253 reports of GBS that occurred within 21 days and 42 days of vaccination, respectively. Within 21 days of vaccination, GBS reporting rates per 1 000 000 doses were 3.29 for Ad26.COV.2, 0.29 for BNT162b2, and 0.35 for mRNA-1273 administered; within 42 days of vaccination, they were 4.07 for Ad26.COV.2, 0.34 for BNT162b2, and 0.44 for mRNA-1273. GBS was more frequently reported within 21 days after Ad26.COV2.S than after BNT162b2 (RRR = 11.40; 95% CI, 8.11-15.99) or mRNA-1273 (RRR = 9.26; 95% CI, 6.57-13.07) vaccination; similar findings were observed within 42 days after vaccination (BNT162b2: RRR = 12.06; 95% CI, 8.86-16.43; mRNA-1273: RRR = 9.27; 95% CI, 6.80-12.63). OE ratios were 3.79 (95% CI, 2.88-4.88) for 21-day and 2.34 (95% CI, 1.83-2.94) for 42-day intervals after Ad26.COV2.S vaccination and less than 1 (not significant) after BNT162b2 and mRNA-1273 vaccination within both postvaccination periods.

CONCLUSIONS AND RELEVANCE

This study found disproportionate reporting and imbalances after Ad26.COV2.S vaccination, suggesting that Ad26.COV2.S vaccination was associated with increased risk for GBS. No associations between mRNA COVID-19 vaccines and risk of GBS were observed.

COVID-19 Vaccination in Korea: Past, Present, and the Way Forward

Since its first emergence in late 2019, severe acute respiratory syndrome coronavirus-2 has claimed more than 6.5 million lives worldwide and continues to infect hundreds of thousands of people daily. To combat this once-in-a-century disaster, several vaccines have been developed at unprecedented speeds. Novel vaccine platforms (messenger ribonucleic acid vaccines and adenoviral vector vaccines) have played a major role in the current pandemic. In Korea, six vaccines, including a domestically developed recombinant vaccine, have been approved. As in other countries, vaccines have been proven to be safe and highly effective in Korea. However, rare serious adverse events and breakthrough infections have undermined public trust in the vaccines, even while the benefits of vaccination far outweigh the risks. The rise of the omicron variant and the subsequent increase in excess mortality demonstrated that while vaccines are a key component of the pandemic response, it alone can fail without non-pharmaceutical interventions like masking and social distancing. The pandemic of coronavirus disease has revealed both the strengths and weaknesses of our healthcare system and pandemic preparedness. When the next pandemic arrives, improved risk communication and vaccine development should be prioritized. To enable timely vaccine development, it is essential to make strategic and sufficient investments in vaccine research and development.

Miller-Fisher syndrome and Guillain-Barre syndrome overlap syndrome following inactivated COVID-19 vaccine: Case report and scope review

Miller-Fisher syndrome (MFS) is a rare variant of Guillain-Barré syndrome (GBS) manifesting as the triad of ataxia, areflexia, and ophthalmoplegia. With the extensive 2019 coronavirus disease (COVID-19) immunization program, cases of GBS or MFS following vaccination are increasingly being reported. A 64-y-old Chinese man presented with new-onset paresthesia of the extremities, bilateral abduction limitation, right facial palsy, areflexia of bilateral lower limbs, and left-dominant limb ataxia 12 d after the second dose of inactivated vaccine against COVID-19. Cerebrospinal fluid analysis indicated albumin-cytological dissociation and was positive for anti-GQ1b IgG and anti-GT1b IgG. Nerve conduction studies of limbs showed evidence of axonal neuropathy with reduced sensory amplitudes. Based on the clinical presentations, temporal progression of symptoms, and laboratory findings, the diagnosis of MFS-GBS overlap syndrome was made. The patient was treated with intravenous immunoglobulin and acupuncture and made a complete recovery 54 d after the onset of his initial neurological signs. To the best of our knowledge, we report the first case of MFS-GBS overlap syndrome following the inactivated COVID-19 vaccination. However, a coincidental relationship with this inactivated vaccine cannot be excluded. Although the benefits of COVID-19 vaccination largely outweigh its risk and the prognosis of MFS is generally favorable, a close surveillance of neurological complications post-COVID-19 vaccination is always necessary, considering its potentially disabling and lethal effects on vaccinated populations.

Guillain-Barré syndrome following influenza vaccination: A 15-year nationwide population-based case-control study

BACKGROUND AND PURPOSE

Influenza vaccination may increase the risk of developing Guillain-Barré syndrome (GBS) due to an elicited immune response, but the exact magnitude and duration of risk is unclear and hence the aim of this study.

METHODS

We conducted a retrospective nationwide population-based case-control study of prospectively collected data on all patients with first-time hospital-diagnosed GBS in Denmark between 2002 and 2016 and 10 age-, sex- and index date-matched population controls per case. The primary exposure was incident influenza vaccination 1 month prior to admission with GBS. We used medical registries to ascertain a complete hospital contact history of pre-existing morbidities. To examine duration of GBS risk, we repeated the analysis for five consecutive 1-month risk periods following vaccination.

RESULTS

Of the 1295 GBS cases and 12,814 controls, 20 cases (1.5%) and 119 controls (0.9%) had received an influenza vaccination within the last month, yielding a comorbidity-adjusted odds ratio of 1.9 (95% confidence interval 1.1-3.2) for GBS. Stratified analyses by calendar time, gender and age showed similar results. The increased risk of GBS was largely confined to 1 month following influenza vaccination. The population-attributable fraction of GBS from influenza vaccination in Denmark was 0.4%.

CONCLUSIONS

Influenza vaccination was associated with a slightly elevated risk of GBS occurrence within 1 month after vaccination. However, only 1.5% of GBS cases in Denmark are associated with recent influenza vaccination. Thus, the benefit of influenza vaccines in preventing influenza infections and associated morbidity and mortality needs to be weighed against the small absolute risk of GBS.

A case of Guillain-Barre syndrome after the second dose of AstraZeneca COVID-19 vaccination

Coronavirus disease 2019 (COVID-19) is a novel virus that primarily involves the respiratory system. Due to the COVID-19 pandemic, an extensive vaccination program is underway worldwide. Herein, we present a 68-year-old woman with paresthesia of both hands associated with gait instability, which started three to four days after receiving the second dose of Oxford/AstraZeneca vaccine against the COVID-19 infection. The acute inflammatory demyelinating polyradiculoneuropathy subtype of the Guillain-Barre syndrome, which is the most common subtype, was diagnosed. Regardless of the beneficial effects of the vaccines, this case report aimed to evaluate their severe complications, such as Guillain-Barre syndrome, to reduce their occurrence in the future.

Guillain-Barré syndrome following coronavirus disease vaccine: First report from Nepal

ChAdOx1 nCoV-19 is an effective and well-tolerated coronavirus disease 2019 vaccine. However, rare cases of serious adverse events have been reported with it. We report a patient who did not have active or prior coronavirus disease 2019 infection, who developed Guillain-Barré syndrome 7 days following the first dose of ChAdOx1 nCoV-19 vaccination. He was treated with intravenous immunoglobulin, with stabilization of the disease. Proper monitoring and prompt reporting of such cases are required to ensure the safety of the vaccine.

Current Approaches to Vaccine Safety Using Observational Data: A Rationale for the EUMAEUS (Evaluating Use of Methods for Adverse Events Under Surveillance-for Vaccines) Study Design

Post-marketing vaccine safety surveillance aims to detect adverse events following immunization in a population. Whether certain methods of surveillance are more precise and unbiased in generating safety signals is unclear. Here, we synthesized information from existing literature to provide an overview of the strengths, weaknesses, and clinical applications of epidemiologic and analytical methods used in vaccine monitoring, focusing on cohort, case-control and self-controlled designs. These designs are proposed to be evaluated in the EUMAEUS (Evaluating Use of Methods for Adverse Event Under Surveillance-for vaccines) study because of their widespread use and potential utility. Over the past decades, there have been an increasing number of epidemiological study designs used for vaccine safety surveillance. While traditional cohort and case-control study designs remain widely used, newer, novel designs such as the self-controlled case series and self-controlled risk intervals have been developed. Each study design comes with its strengths and limitations, and the most appropriate study design will depend on availability of resources, access to records, number and distribution of cases, and availability of population coverage data. Several assumptions have to be made while using the various study designs, and while the goal is to mitigate any biases, violations of these assumptions are often still present to varying degrees. In our review, we discussed some of the potential biases (i.e., selection bias, misclassification bias and confounding bias), and ways to mitigate them. While the types of epidemiological study designs are well established, a comprehensive comparison of the analytical aspects (including method evaluation and performance metrics) of these study designs are relatively less well studied. We summarized the literature, reporting on two simulation studies, which compared the detection time, empirical power, error rate and risk estimate bias across the above-mentioned study designs. While these simulation studies provided insights on the analytic performance of each of the study designs, its applicability to real-world data remains unclear. To bridge that gap, we provided the rationale of the EUMAEUS study, with a brief description of the study design; and how the use of real-world multi-database networks can provide insights into better methods evaluation and vaccine safety surveillance.

A Comparative Analysis of COVID-19 Vaccines Based on over 580,000 Cases from the Vaccination Adverse Event Reporting System

Background: The COVID-19 pandemic is being battled via the largest vaccination campaign in history, with more than eight billion doses administered thus far. Therefore, discussions about potentially adverse reactions, and broader safety concerns, are critical. The U.S. Vaccination Adverse Event Reporting System (VAERS) has recorded vaccination side effects for over 30 years. About 580,000 events have been filed for COVID-19 thus far, primarily for the Johnson & Johnson (New Jersey, USA), Pfizer/BioNTech (Mainz, Germany), and Moderna (Cambridge, USA) vaccines. Methods: Using available databases, we evaluated these three vaccines in terms of the occurrence of four generally-noticed adverse reactions—namely, cerebral venous sinus thrombosis, Guillain−Barré syndrome (a severe paralytic neuropathy), myocarditis, and pericarditis. Our statistical analysis also included a calculation of odds ratios (ORs) based on total vaccination numbers, accounting for incidence rates in the general population. Results: ORs for a number of adverse events and patient groups were (largely) increased, most notably for the occurrence of cerebral venous sinus thrombosis after vaccination with the Johnson & Johnson vaccine. The overall population OR of 10 increases to 12.5 when limited to women, and further yet (to 14.4) among women below age 50 yrs. In addition, elevated risks were found (i) for Guillain−Barré syndrome (OR of 11.6) and (ii) for myocarditis/pericarditis (ORs of 5.3/4.1, respectively) among young men (<25 yrs) vaccinated with the Pfizer/BioNTech vaccine. Conclusions: Any conclusions from such a retrospective, real-world data analysis must be drawn cautiously, and should be confirmed by prospective double-blinded clinical trials. In addition, we emphasize that the adverse events reported here are not specific side effects of COVID vaccines, and the significant, well-established benefits of COVID-19 vaccination outweigh the potential complications surveyed here.

COVID-19 vaccination and Guillain-Barré syndrome: analyses using the National Immunoglobulin Database

Vaccination against viruses has rarely been associated with Guillain-Barré syndrome (GBS), and an association with the COVID-19 vaccine is unknown. We performed a population-based study of National Health Service data in England and a multicentre surveillance study from UK hospitals to investigate the relationship between COVID-19 vaccination and GBS. Firstly, case dates of GBS identified retrospectively in the National Immunoglobulin Database from 8 December 2021 to 8 July 2021 were linked to receipt dates of COVID-19 vaccines using data from the National Immunisation Management System in England. For the linked dataset, GBS cases temporally associated with vaccination within a 6-week risk window of any COVID-19 vaccine were identified. Secondly, we prospectively collected incident UK-wide (four nations) GBS cases from 1 January 2021 to 7 November 2021 in a separate UK multicentre surveillance database. For this multicentre UK-wide surveillance dataset, we explored phenotypes of reported GBS cases to identify features of COVID-19 vaccine-associated GBS. Nine hundred and ninety-six GBS cases were recorded in the National Immunoglobulin Database from January to October 2021. A spike of GBS cases above the 2016-2020 average occurred in March-April 2021. One hundred and ninety-eight GBS cases occurred within 6 weeks of the first-dose COVID-19 vaccination in England [0.618 cases per 100,000 vaccinations; 176 ChAdOx1 nCoV-19 (AstraZeneca), 21 tozinameran (Pfizer) and one mRNA-1273 (Moderna)]. The 6-week excess of GBS (compared to the baseline rate of GBS cases 6-12 weeks after vaccination) occurred with a peak at 24 days post-vaccination; first-doses of ChAdOx1 nCoV-19 accounted for the excess. No excess was seen for second-dose vaccination. The absolute number of excess GBS cases from January-July 2021 was between 98-140 cases for first-dose ChAdOx1 nCoV-19 vaccination. First-dose tozinameran and second-dose of any vaccination showed no excess GBS risk. Detailed clinical data from 121 GBS patients were reported in the separate multicentre surveillance dataset during this timeframe. No phenotypic or demographic differences identified between vaccine-associated and non-vaccinated GBS cases occurring in the same timeframe. Analysis of the linked NID/NIMS dataset suggested that first-dose ChAdOx1 nCoV-19 vaccination is associated with an excess GBS risk of 0.576 (95% confidence interval 0.481-0.691) cases per 100 000 doses. However, examination of a multicentre surveillance dataset suggested that no specific clinical features, including facial weakness, are associated with vaccination-related GBS compared to non-vaccinated cases. The pathogenic cause of the ChAdOx1 nCoV-19 specific first dose link warrants further study.

Interpretation of vaccine associated neurological adverse events: a methodological and historical review

As a result of significant recent scientific investment, the range of vaccines available for COVID-19 prevention continues to expand and uptake is increasing globally. Although initial trial safety data have been generally reassuring, a number of adverse events, including vaccine induced thrombosis and thrombocytopenia (VITT), have come to light which have the potential to undermine the success of the vaccination program. However, it can be difficult to interpret available data and put these into context and to communicate this effectively. In this review, we discuss contemporary methodologies employed to investigate possible associations between vaccination and adverse neurological outcomes and why determining causality can be challenging. We demonstrate these issues by discussing relevant historical exemplars and explore the relevance for the current pandemic and vaccination program. We also discuss challenges in understanding and communicating such risks to clinicians and the general population within the context of the 'infodemic' facilitated by the Internet and other media.

Severe Acute Motor Axonal Neuropathy associated with Influenza-A (H1N1) Infection and Prolonged Respiratory Failure - A Case Report

Acute Motor Axonal Neuropathy (AMAN) is an immune-mediated disorder of the peripheral nervous system, part of the spectrum of the Guillain-Barre syndrome (GBS). An infectious event most often triggers it reported a few weeks before the onset. The reported case is of a 56 years-old woman who developed acute motor axonal neuropathy three weeks after respiratory infection with influenza A virus subtype H1N1. Despite early treatment with plasmapheresis and intravenous immunoglobulins, the patient remained tetraplegic, mechanically ventilated for five months, with repetitive unsuccessful weaning trails. The probable cause was considered to be phrenic nerve palsy in the context of acute motor axonal neuropathy. This case highlights that acute motor axonal neuropathy is a severe and life-threatening form of Guillain-Barre syndrome associated with significant mortality and morbidity. Neurological and physical recovery strongly depend on the inter-professional effort in an intensive care unit and neurology professionals.

Patients' attitude towards vaccination after Guillain Barré syndrome

BACKGROUND AND AIMS

Guillain Barré syndrome (GBS) could be triggered by an infectious disease but by vaccination as well. Thus, suffering GBS may influence patients' attitudes towards vaccination.

METHODS

An anonymous questionnaire consisting of the Overall Neuropathy Limitations Score (ONLS), the short form-36 health survey (SF-36), and questions addressing patients' attitude towards vaccination was sent to members of a German GBS support group and to patients with GBS diagnosis who were treated at Jena University Hospital.

RESULTS

Ninety-seven questionnaires clearly stated GBS as a diagnosis and were included in the analysis. Although 19.6% of the GBS patients reported having no disability in the long-time follow-up, a considerable number of patients still had persistent neurological symptoms; 74.2% of the GBS patients reported being able to walk at least 10 m independently. However, 5.2% were restricted to wheelchair. The patients reached lower scores in all domains of quality of life compared to German controls. Moreover, patients showed a more critical attitude towards vaccination compared to a German representative survey. Fewer patients (58.8%) received a vaccination after suffering from GBS than before (77.3%). Every tenth patient believed that vaccination was the trigger for the GBS. 32% of the patients did not receive a vaccination in the last 5 years mainly because of the fear of adverse effects (32%) or disadvise of the general practitioners (25.8%).

DISCUSSION

Although the risk of relapse following immunization may be rather low, uncertainties and fears still impair the counseling of these patients by their medical practitioner.

Miller-Fisher Syndrome and Guillain-Barre Syndrome overlap syndrome in a patient post Oxford-AstraZeneca SARS-CoV-2 vaccination

We describe a patient who developed bilateral oculomotor nerve palsy, ataxia, facial diplegia and lower limb weakness 2 weeks post-Oxford-AstraZeneca SARS-CoV2 vaccination, consistent with Miller-Fisher syndrome (MFS) and Guillain-Barre syndrome (GBS) overlap syndrome. Although some features of the patient's presentation were typical of recently reported cases of a rare GBS variant post-Oxford-AstraZeneca vaccination, including severe facial weakness and a lack of respiratory involvement, to our knowledge this is the first reported case of MFS associated with SARS-CoV2 vaccination. While postvaccination GBS remains rare, it appears to have a favourable prognosis, and recognising this entity is therefore important for patient counselling and monitoring for potential complications.

To be, or not to be… Guillain-Barré Syndrome

Guillain-Barré Syndrome (GBS) is currently the most frequent cause of acute flaccid paralysis on a global scale, being an autoimmune disorder wherein demyelination of the peripheral nerves occurs. Its main clinical features are a symmetrical ascending muscle weakness with reduced osteotendinous reflexes and variable sensory involvement. GBS most commonly occurs after an infection, especially viral (including COVID-19), but may also transpire after immunization with certain vaccines or in the development of specific malignancies. Immunoglobulins, plasmapheresis, and glucocorticoids represent the principal treatment modalities, however patients with severe disease progression may require supportive therapy in an intensive care unit. Due to its symptomology, which overlaps with numerous neurological and infectious illnesses, the diagnosis of GBS may often be misattributed to pathologies that are essentially different from this syndrome. Moreover, many of these require specific treatment methods distinct to those recommended for GBS, in lack of which the prognosis of the patient is drastically affected. Such diseases include exposure to toxins either environmental or foodborne, central nervous system infections, metabolic or serum ion alterations, demyelinating pathologies, or even conditions amenable to neurosurgical intervention. This extensive narrative review aims to systematically and comprehensively tackle the most notable and challenging differential diagnoses of GBS, emphasizing on the clinical discrepancies between the diseases, the appropriate paraclinical investigations, and suitable management indications.

A Rare Case of Guillain-Barré Syndrome With Severe Pandysautonomia

Acute pandysautonomia is a rare disorder characterized by autonomic failure affecting sympathetic, parasympathetic, and enteric functions. We present a case of acute inflammatory demyelinating polyneuropathy (AIDP) with severe pandysautonomia in a young, otherwise healthy, female who presented with gastrointestinal symptoms and sensory demyelinating polyneuropathy, which progressively worsened and subsequently developed bladder dysfunction and orthostatic hypotension. We discuss the challenges with diagnostic workup as well as the challenges we encountered as part of the management.

Vaccinomics: a cross-sectional survey of public values

Objective: We characterize public values regarding vaccinomics, which aims to improve vaccine safety and effectiveness using genomics.Methods: Panel survey (2020) of ≥18-year-olds with embedded animation introduced vaccinomics. Sociodemographic, health, and vaccination-related items were adapted from validated scales. Novel items measured trust in public health authorities, vaccinomics-related values, and preferences for federal funding: vaccinomics compared with vaccine issues and chronic diseases. Beginning and end of survey confidence in vaccine safety was measured to assess potential changes. Data were weighted to the U.S. Census. Vaccinomics-related concerns were stratified by sociodemographic characteristics, vaccine hesitancy status (composite outcome), reported serious vaccine reactions, and trust in public health authorities (PHA). Log binomial regression models estimated associations between these variables and agency to make vaccine-related decisions.Results: Most (70.7%, N = 1,925) respondents expected vaccinomics would increase their vaccine confidence compared to now. Agreement was highest among those without serious vaccine reaction experience (unexperienced: 74.2% versus experienced: 62.3%), with high trust in PHA (high: 83.3% versus low: 57.4%), and low vaccine hesitancy among parents of teenagers (low: 78.8% versus high: 62.5%) and adults without minor children (low: 79.8% versus high: 60.6%; all p < .01). Belief that vaccination was an individual's choice was associated with reported serious reactions (adjusted Prevalence Ratio (aPR): 1.16; 95% CI: 1.07, 1.25) and low trust (aPR: 0.91; 0.84, 0.98). Beginning versus end of survey vaccine safety perceptions were similar.Conclusion: Federal funding, communications, and policies should assure the public that vaccinomics will not remove their decision-making power and engender trust in PHA.

Iatrogenic immune-mediated neuropathies: diagnostic, epidemiological and mechanistic uncertainties for causality and implications for clinical practice

Acute and chronic immune-mediated neuropathies have been widely reported with medical intervention. Although causal relationship may be uncertain in many cases, a variety of drugs, several vaccination types, surgical procedures and bone marrow transplants have been reported as possible cause or trigger of a putative immune-mediated response resulting in acute and chronic neuropathies. We conducted a systematic review of the literature from 1966 to 2020 on reported cases of possible iatrogenic immune-mediated neuropathies. We determined in each case the likelihood of causality based on frequency of the association, focusing primarily on clinical presentation and disease course as well as available ancillary investigations (electrophysiology, blood and cerebrospinal fluid and neuropathology). The response to immunotherapy and issue of re-exposure were also evaluated. We also considered hypothesised mechanisms of onset of immune-mediated neuropathy in the specific iatrogenic context. We believe that a likely causal relationship exists for only few drugs, mainly antitumour necrosis factor alpha agents and immune checkpoint inhibitors, but remains largely unsubstantiated for most other suggested iatrogenic causes. Unfortunately, given the lack of an accurate diagnostic biomarker for most immune-mediated neuropathies, clinical assessment will often override ancillary investigations, resulting in lower levels of certainty that may continue to cast serious doubts on reliability of their diagnosis. Consequently, future reports of suspected cases should collect and exhaustively assess all relevant data. At the current time, besides lack of evidence for causality, the practical implications on management of suspected cases is extremely limited and therapeutic decisions appear likely no different to those made in non-iatrogenic cases.

Guillain-Barré syndrome following ChAdOx1 nCoV-19 COVID-19 vaccination: A case series

ChAdOx1 nCoV-19 is an effective and well-tolerated coronavirus disease 2019 (COVID-19) vaccine. Rare cases of serious adverse events have been reported with this vaccine. We report three patients who developed Guillain-Barré syndrome following ChAdOx1 nCoV-19 vaccination, who did not have active or prior COVID-19 infection. The neurological illness in all patients had an onset of 11-13 days after the first dose of vaccine. All were characterized by sensorimotor weakness of the upper and lower limbs, with facial diplegia in one and dysautonomia in the other. Nerve conduction studies were consistent with demyelination in two and axonopathy in one. Cerebrospinal fluid analysis showed albuminocytological dissociation in two patients. All patients had moderate-to-severe disability. They were treated with intravenous immunoglobulin, with stabilization of the disease. Proper monitoring and prompt reporting of such cases is required to ensure safety of the vaccine.

Influenza Vaccination for the Prevention of Cardiovascular Disease in the Americas: Consensus document of the Inter-American Society of Cardiology and the Word Heart Federation

Background

Cardiovascular mortality is decreasing but remains the leading cause of death world-wide. Respiratory infections such as influenza significantly contribute to morbidity and mortality in patients with cardiovascular disease. Despite of proven benefits, influenza vaccination is not fully implemented, especially in Latin America.

Objective

The aim was to develop a regional consensus with recommendations regarding influenza vaccination and cardiovascular disease.

Methods

A multidisciplinary team composed by experts in the management and prevention of cardiovascular disease from the Americas, convened by the Inter-American Society of Cardiology (IASC) and the World Heart Federation (WHF), participated in the process and the formulation of statements. The modified RAND/UCLA methodology was used. This document was supported by a grant from the WHF.

Results

An extensive literature search was divided into seven questions, and a total of 23 conclusions and 29 recommendations were achieved. There was no disagreement among experts in the conclusions or recommendations.

Conclusions

There is a strong correlation between influenza and cardiovascular events. Influenza vaccination is not only safe and a proven strategy to reduce cardiovascular events, but it is also cost saving. We found several barriers for its global implementation and potential strategies to overcome them.

Vaccinations and Autoimmune Diseases

Vaccines represent one of the most effective measures of public health medicine, saving countless lives and preventing lifelong disabilities. Vaccines are extremely safe, however, no vaccine is completely free from risks and adverse events can occur following vaccination. An adverse event following immunization (AEFI) may be a true adverse reaction caused by the vaccine or an event that temporally occurred after immunization but is not caused by it. Among the adverse reactions to vaccines, one of the most feared is the triggering of autoimmune diseases, which are a heterogeneous group of disorders characterized by dysregulation of the immune system. Currently, no mechanisms have been demonstrated that could explain the correlation between vaccination and the development of autoimmune diseases. Furthermore, epidemiological studies do not support the hypothesis that vaccines cause systemic autoimmune diseases. The only confirmed associations, although very rare, are those between the flu vaccine and Guillain-Barré syndrome, especially with old vaccine preparations, and measles-mumps-rubella (MMR) vaccine and thrombocytopenia. Due to the SARS-CoV2 pandemic, new types of vaccines have been developed and are now available. Close vaccine safety-surveillance is currently underway for these new vaccines.

Case of Guillain-Barré syndrome following COVID-19 vaccine

Guillain-Barré syndrome (GBS) is a rare immune-mediated disorder of the peripheral nerves. Although its cause is not fully understood, the syndrome often follows infection with a virus or bacteria, although in rare occasions, vaccination may precede GBS. We describe a case of a 62-year-old woman who presented with paraesthesia and progressive weakness of both lower limbs over 3 days. Clinical examination and investigation findings including lumbar puncture and nerve conduction studies were consistent with the diagnosis of GBS. She had no history of either diarrhoea or respiratory tract infections preceding her presentation. However, she had her first intramuscular dose of the Oxford/AstraZeneca COVID-19 vaccine 11 days prior to her presentation. Although no direct link could be ascertained, the purpose of this report is to highlight the incidence and consider this issue while evaluating any case of GBS in the light of the current pandemic and vaccination programme.

Papillomavirus vaccination and Guillain-Barre Syndrome among girls: A cohort study in Spain

BACKGROUND

Studies of the association of Guillain-Barré Syndrome (GBS) with papillomavirus vaccination (HPVv; scheduled from 2007) have provided contradicting results, probably due to the low frequency of this disease. We aimed at estimating that risk relative to non-vaccination among girls, by using the Spanish Primary Care Database for Pharmacoepidemiological Research (BIFAP).

METHODS

A cohort study of girls aged 9-18 years during 2007-2016 free of GBS or HPVv was selected and followed up to GBS diagnosis. Follow-up time was divided by time-varying HPVv exposure and confounders. Crude Incidence rates (IR per 1,000,000 person-years (py)) and adjusted Hazard Ratios (HR) of GBS were estimated anytime after vaccination compared to non-exposed periods. HRs were also estimated for the first 90 days after HPVv (risk-window) and thereafter.

RESULTS

Out of 388,849 girls, of which 154,255 were vaccinated, 6 'confirmed' GBS cases occurred during non-exposure periods (IR of 5.83 per million person-years; 95% CI: 2.62-12.97) and 3 'confirmed' cases anytime after vaccination (IR of 7.87; 95% CI: 2.54-24.39). The resulting adjusted HR anytime after vaccination was 1.24 (95% CI: 0.19-8.00). All three cases occurred after the risk window of 90 days with an HR of 1.77 (95% CI: 0.25-12.54) for post-exposure periods as compared with non-exposure. Since zero cases occurred during the risk window, no HR could be estimated for exposed periods.

CONCLUSIONS

Incidences of GBS were in line with the range previously reported for young people, supporting the potential of BIFAP for performing studies on GBS. However, a lack of power may be present for quantifying the relative risk of such a rare disease after the vaccination among the study cohort, where we can only exclude an increased risk of 8-times relative to no vaccination.

Emerging infectious diseases, vaccines and Guillain-Barré syndrome

The recent outbreak of Zika virus infection increased the incidence of Guillain–Barré syndrome (GBS). Following the first reported case of GBS after Zika virus infection in 2013, there has been a considerable increase in the incidence of GBS in endemic countries, such as French Polynesia and Latin American countries. The association between coronavirus disease 2019 (COVID‐19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), and GBS is another emerging research hotspot. Electrophysiological studies have suggested that GBS patients associated with Zika virus infection or COVID‐19 tend to manifest acute inflammatory demyelinating polyneuropathy, rather than acute motor axonal neuropathy (AMAN). Causative autoantibodies, such as anti‐ganglioside antibodies in AMAN associated with Campylobacter jejuni infection, have not been identified in GBS associated with these emerging infectious diseases. Nevertheless, recent studies suggested molecular mimicry between these viruses and human proteins related to GBS. Recent studies have shown the efficacy of new vaccines, containing artificial messenger RNA encoding the spike protein of SARS‐CoV‐2, against COVID‐19. These vaccines are now available in many countries and massive vaccination campaigns are currently ongoing. Although there are long‐standing concerns about the increased risk of GBS after inoculation of conventional vaccines, the risk of GBS is not considered a legitimate reason to limit administration of currently available vaccines, because the benefits outweigh the risks.

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

Safety monitoring is of paramount importance for vaccines authorized for emergent use (EUA) by the US Food and Drug Administration (FDA) against SARS-CoV-2. Mass immunization is an essential tool to end the current pandemic, but vaccine surveillance is necessary to identify any potentially associated harms. At the same time, probability of temporal bias should be borne in mind before making conclusions about causality between the vaccine and an attributable undesired effect. We report a case of Guillain-Barré syndrome after the first dose of SARS-CoV-2 vaccine and believe this is a temporal, rather than causal association.