Investigation of the temporal association of Guillain-Barre syndrome with influenza vaccine and influenzalike illness using the United Kingdom General Practice Research Database

Vaccine patterns among older adults with Guillain-Barré syndrome and matched comparators, 2006-2019

BACKGROUND

Some vaccines have a small risk of triggering Guillain-Barré syndrome (GBS), an autoimmune disorder where nerve damage leads to paralysis. There is a CDC precaution for patients whose GBS was associated with an influenza or tetanus toxoid-containing vaccine (GBS occurring within 42 days following vaccination).

METHODS

We described vaccine patterns before and after a GBS diagnosis with a matched cohort design in a 20% random sample of fee-for-service Medicare enrollees. We defined the index date as an ICD-9-CM or ICD-10-CM GBS diagnosis code in the primary position of an inpatient claim. We matched each GBS patient to five non-GBS comparators on sex, exact age, racial and ethnic category, state of residence and the month of preventive health visits during baseline; used weighting to balance covariates; and measured frequency of vaccines received per 100 people during year before and after the index date using the weighted mean cumulative count (wMCC).

RESULTS

We identified 1567 patients with a GBS diagnosis with at least 1 year of prior continuous enrollment in Medicare A and B that matched to five comparators each. The wMCCs in the 1 year before the index date were similar for both groups, with a wMCC of 74 vaccines/100 people in the GBS group (95% CI 71, 77). Within 1 year after the index date, patients with GBS had received 26 vaccines/100 people (95% CI 23, 28), which was 41 fewer vaccines than matched non-GBS comparators (95% CI -44, -38). Among GBS patients, 11% were diagnosed with GBS within 42 days after a vaccine.

CONCLUSIONS

GBS diagnosis has a strong impact on reducing subsequent vaccination even though there is no warning or precaution about future vaccines for most patients diagnosed with GBS. These data suggest discordance between clinical practice and current vaccine recommendations.

Strength of Association between Coronavirus Disease 2019 and Neurological Disorders in Children: A Case-Control Study

INTRODUCTION

Evidence suggests potential neurological complications of coronavirus disease 2019 (COVID-19), particularly in adults. While case series have hinted at associations between COVID-19 and neurological disorders (NDs) in children, the extent of this link remains unclear. This study investigates temporal trends in NDs during the pandemic and assesses their potential association with COVID-19 infection in children.

METHODS

We analyzed national Thai hospitalization data (2017-2022) for children under 18 with specific NDs (acute transverse myelitis, central nervous system demyelination, neuromyelitis optica, optic neuritis, polyneuropathy, stroke). An interrupted time series analysis was employed to identify changes in the incidence trends of NDs following the declaration of the COVID-19 pandemic. A matched case-control analysis was conducted using data specific to the Thai COVID-19 outbreak period. This analysis aimed to estimate the association between recent/concurrent COVID-19 infection and NDs in children. A propensity score matching on age group, sex, and month of admission was performed before conducting logistic regression.

RESULTS

From 2017-2022, 1,721 children were admitted with NDs (2,474 admissions), with a male predominance (55%) and average age of 10.6 years. Significant slope change was observed in optical neuritis trends coinciding with the third COVID-19 wave. The case-control analysis included 468 cases and 2,340 controls. Children with NDs had a significantly higher prevalence of recent/concurrent COVID-19 (matched odds ratio: 1.95, 95% confidence interval: 1.21-3.16). Subgroup analysis revealed an association between stroke and recent/concurrent COVID-19 (matched odds ratio: 3.05, 95% confidence interval: 1.3-7.16). Thus, this study suggests an association between recent/concurrent COVID-19 and NDs, especially pediatric stroke.

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.

SARS-CoV-2 Vaccination Safety in Guillain-Barré Syndrome, Chronic Inflammatory Demyelinating Polyneuropathy, and Multifocal Motor Neuropathy

BACKGROUND AND OBJECTIVES

There are concerns on the safety of SARS-CoV-2 vaccination in patients with a history of Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and multifocal motor neuropathy (MMN). The aim of this study was to determine the risk of recurrence of GBS and exacerbations of CIDP or MMN after SARS-CoV-2 vaccination.

METHODS

We conducted a prospective, multicenter cohort study from January 2021 to August 2021. Patients known in 1 of 3 Dutch University Medical Centers with research focus on immune-mediated neuropathy and members of the Dutch Patient Association for Neuromuscular Diseases were invited to participate if they were 18 years or older and diagnosed with GBS, CIDP, or MMN. Participants completed a series of questionnaires at 4 different time points: study baseline (1), within 48 hours before any SARS-CoV-2 vaccination (2 and 3, if applicable), and 6 weeks after their last vaccination (4). Participants unwilling to get vaccinated completed the last questionnaire (4) 4 months after study baseline. We assessed recurrences of GBS, any worsening of CIDP or MMN-related symptoms, treatment alterations, and hospitalization.

RESULTS

Of 1,152 individuals to whom we sent the questionnaires, 674 (59%) signed informed consent. We excluded 153 individuals, most often because they had already received a SARS-CoV-2 vaccination or had had the infection (84%) before study baseline. Of 521 participants included in analyses, 403 (81%) completed the last questionnaire (time point 4). None of 162 participants with a history of GBS had a recurrence after vaccination. Of 188 participants with CIDP, 10 participants (5%) reported a worsening of symptoms within 6 weeks after vaccination. In 5 (3%) of these patients, maintenance treatment was modified. Two of 53 participants with MMN (4%) reported a worsening of symptoms, and treatment modification was reported by 1 participant.

DISCUSSION

We found no increased risk of GBS recurrence and a low to negligible risk of worsening of CIDP or MMN-related symptoms after SARS-CoV-2 vaccination. Based on our data, SARS-CoV-2 vaccination in patients with these immune-mediated neuropathies seems to be safe.

Thrombosis and thrombocytopenia after vaccination against and infection with SARS-CoV-2 in the United Kingdom

Population-based studies can provide important evidence on the safety of COVID-19 vaccines. Using data from the United Kingdom, here we compare observed rates of thrombosis and thrombocytopenia following vaccination against SARS-CoV-2 and infection with SARS-CoV-2 with background (expected) rates in the general population. First and second dose cohorts for ChAdOx1 or BNT162b2 between 8 December 2020 and 2 May 2021 in the United Kingdom were identified. A further cohort consisted of people with no prior COVID-19 vaccination who were infected with SARS-Cov-2 identified by a first positive PCR test between 1 September 2020 and 2 May 2021. The fourth general population cohort for background rates included those people in the database as of 1 January 2017. In total, we included 3,768,517 ChAdOx1 and 1,832,841 BNT162b2 vaccinees, 401,691 people infected with SARS-CoV-2, and 9,414,403 people from the general population. An increased risk of venous thromboembolism was seen after first dose of ChAdOx1 (standardized incidence ratio: 1.12 [95% CI: 1.05 to 1.20]), BNT162b2 (1.12 [1.03 to 1.21]), and positive PCR test (7.27 [6.86 to 7.72]). Rates of cerebral venous sinus thrombosis were higher than otherwise expected after first dose of ChAdOx1 (4.14 [2.54 to 6.76]) and a SARS-CoV-2 PCR positive test (3.74 [1.56 to 8.98]). Rates of arterial thromboembolism after vaccination were no higher than expected but were increased after a SARS-CoV-2 PCR positive test (1.39 [1.21 to 1.61]). Rates of venous thromboembolism with thrombocytopenia were higher than expected after a SARS-CoV-2 PCR positive test (5.76 [3.19 to 10.40]).

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.

An International Perspective on Preceding Infections in Guillain-Barré Syndrome: The IGOS-1000 Cohort

BACKGROUND AND OBJECTIVES

Infections play a key role in the development of Guillain-Barré syndrome (GBS) and have been associated with specific clinical features and disease severity. The clinical variation of GBS across geographical regions has been suggested to be related to differences in the distribution of preceding infections, but this has not been studied on a large scale.

METHODS

We analyzed the first 1,000 patients included in the International GBS Outcome Study with available biosamples (n = 768) for the presence of a recent infection with Campylobacter jejuni, hepatitis E virus, Mycoplasma pneumoniae, cytomegalovirus, and Epstein-Barr virus.

RESULTS

Serologic evidence of a recent infection with C. jejuni was found in 228 (30%), M. pneumoniae in 77 (10%), hepatitis E virus in 23 (3%), cytomegalovirus in 30 (4%), and Epstein-Barr virus in 7 (1%) patients. Evidence of more than 1 recent infection was found in 49 (6%) of these patients. Symptoms of antecedent infections were reported in 556 patients (72%), and this proportion did not significantly differ between those testing positive or negative for a recent infection. The proportions of infections were similar across continents. The sensorimotor variant and the demyelinating electrophysiologic subtype were most frequent across all infection groups, although proportions were significantly higher in patients with a cytomegalovirus and significantly lower in those with a C. jejuni infection. C. jejuni-positive patients were more severely affected, indicated by a lower Medical Research Council sum score at nadir (p = 0.004) and a longer time to regain the ability to walk independently (p = 0.005). The pure motor variant and axonal electrophysiologic subtype were more frequent in Asian compared with American or European C. jejuni-positive patients (p < 0.001, resp. p = 0.001). Time to nadir was longer in the cytomegalovirus-positive patients (p = 0.004).

DISCUSSION

Across geographical regions, the distribution of infections was similar, but the association between infection and clinical phenotype differed. A mismatch between symptom reporting and serologic results and the high frequency of coinfections demonstrate the importance of broad serologic testing in identifying the most likely infectious trigger. The association between infections and outcome indicates their value for future prognostic models.

Risk of Guillain-Barré Syndrome Among Older Adults Receiving Influenza Vaccine in Taiwan

IMPORTANCE

Although influenza vaccination has been associated with Guillain-Barré syndrome (GBS), the findings among studies of older adult populations are inconsistent.

OBJECTIVE

To determine the risk of GBS after influenza vaccination among older adults.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study incorporated a self-controlled case series design. Days 1 to 7, days 1 to 14, and days 1 to 42 after influenza vaccination were identified as risk intervals; days 8 to 180, days 15 to 180, and days 43 to 180 comprised the corresponding control interval. Population-based data were obtained from Taiwan's National Health Insurance research database between January 1, 2003, and December 31, 2017. Data were analyzed from November 1, 2021, through February 28, 2022. Adults 65 years or older who developed GBS within 180 days after influenza vaccination were enrolled.

EXPOSURE

Government-funded seasonal influenza vaccination.

MAIN OUTCOMES AND MEASURES

Onset of GBS during risk intervals after influenza vaccination compared with control intervals using Poisson regression to calculate incidence rate ratio (IRR).

RESULTS

Of 13 482 122 adults aged 65 years or older who received an influenza vaccination, 374 were hospitalized for GBS. The mean (SD) age of the study population was 75.0 (6.1) years; 215 (57.5%) were men and 159 (42.5%) were women. In terms of comorbidities, 33 adults (8.8%) had cancer and 4 (1.1%) had autoimmune diseases. The IRRs for GBS during days 1 to 7, days 1 to 14, and days 1 to 42 were 0.95 (95% CI, 0.55-1.61; P = .84), 0.87 (95% CI, 0.58-1.29; P = .48), and 0.92 (95% CI, 0.72-1.17; P = .49), respectively. No results showed statistical significance. Similarly, no significant differences in IRRs were noted for the overall risk interval (ie, days 1-42) in subgroup analyses pertaining to different age groups (65-74 years [0.93 (95% CI, 0.66-1.31)], 75-84 years [0.85 (95% CI, 0.58-1.26)], and ≥85 years [1.10 (95% CI, 0.57-2.11)]), sex (men, 0.97 [95% CI, 0.71-1.33; P = .87]; women, 0.85 [95% CI, 0.58-1.23; P = .39]), Charlson Comorbidity Index (1.03 [95% CI, 0.77-1.38; P = .84]), or comorbidities (cancer, 0.68 [95% CI, 0.28-1.64; P = .39]; autoimmune disease, 1.10 [95% CI, 0.11-10.53; P = .94]).

CONCLUSIONS AND RELEVANCE

These findings suggest that influenza vaccination did not increase the risk of GBS among adults aged 65 years or older in Taiwan regardless of postvaccination period or underlying characteristics.

Safety of COVID-19 vaccination and acute neurological events: A self-controlled case series in England using the OpenSAFELY platform

INTRODUCTION

We investigated the potential association of COVID-19 vaccination with three acute neurological events: Guillain-Barré syndrome (GBS), transverse myelitis and Bell's palsy.

METHODS

With the approval of NHS England we analysed primary care data from >17 million patients in England linked to emergency care, hospital admission and mortality records in the OpenSAFELY platform. Separately for each vaccine brand, we used a self-controlled case series design to estimate the incidence rate ratio for each outcome in the period following vaccination (4-42 days for GBS, 4-28 days for transverse myelitis and Bell's palsy) compared to a within-person baseline, using conditional Poisson regression.

RESULTS

Among 7,783,441 ChAdOx1 vaccinees, there was an increased rate of GBS (N = 517; incidence rate ratio 2·85; 95% CI2·33-3·47) and Bell's palsy (N = 5,350; 1·39; 1·27-1·53) following a first dose of ChAdOx1 vaccine, corresponding to 11.0 additional cases of GBS and 17.9 cases of Bell's palsy per 1 million vaccinees if causal. For GBS this applied to the first, but not the second, dose. There was no clear evidence of an association of ChAdOx1 vaccination with transverse myelitis (N = 199; 1·51; 0·96-2·37). Among 5,729,152 BNT162b2 vaccinees, there was no evidence of any association with GBS (N = 283; 1·09; 0·75-1·57), transverse myelitis (N = 109; 1·62; 0·86-3·03) or Bell's palsy (N = 3,609; 0·89; 0·76-1·03). Among 255,446 mRNA-1273 vaccine recipients there was no evidence of an association with Bell's palsy (N = 78; 0·88, 0·32-2·42).

CONCLUSIONS

COVID-19 vaccines save lives, but it is important to understand rare adverse events. We observed a short-term increased rate of Guillain-Barré syndrome and Bell's palsy after first dose of ChAdOx1 vaccine. The absolute risk, assuming a causal effect attributable to vaccination, was low.

Association between covid-19 vaccination, SARS-CoV-2 infection, and risk of immune mediated neurological events: population based cohort and self-controlled case series analysis

OBJECTIVE

To study the association between covid-19 vaccines, SARS-CoV-2 infection, and risk of immune mediated neurological events.

DESIGN

Population based historical rate comparison study and self-controlled case series analysis.

SETTING

Primary care records from the United Kingdom, and primary care records from Spain linked to hospital data.

PARTICIPANTS

8 330 497 people who received at least one dose of covid-19 vaccines ChAdOx1 nCoV-19, BNT162b2, mRNA-1273, or Ad.26.COV2.S between the rollout of the vaccination campaigns and end of data availability (UK: 9 May 2021; Spain: 30 June 2021). The study sample also comprised a cohort of 735 870 unvaccinated individuals with a first positive reverse transcription polymerase chain reaction test result for SARS-CoV-2 from 1 September 2020, and 14 330 080 participants from the general population.

MAIN OUTCOME MEASURES

Outcomes were incidence of Bell's palsy, encephalomyelitis, Guillain-Barré syndrome, and transverse myelitis. Incidence rates were estimated in the 21 days after the first vaccine dose, 90 days after a positive test result for SARS-CoV-2, and between 2017 and 2019 for background rates in the general population cohort. Indirectly standardised incidence ratios were estimated. Adjusted incidence rate ratios were estimated from the self-controlled case series.

RESULTS

The study included 4 376 535 people who received ChAdOx1 nCoV-19, 3 588 318 who received BNT162b2, 244 913 who received mRNA-1273, and 120 731 who received Ad26.CoV.2; 735 870 people with SARS-CoV-2 infection; and 14 330 080 people from the general population. Overall, post-vaccine rates were consistent with expected (background) rates for Bell's palsy, encephalomyelitis, and Guillain-Barré syndrome. Self-controlled case series was conducted only for Bell's palsy, given limited statistical power, but with no safety signal seen for those vaccinated. Rates were, however, higher than expected after SARS-CoV-2 infection. For example, in the data from the UK, the standardised incidence ratio for Bell's palsy was 1.33 (1.02 to 1.74), for encephalomyelitis was 6.89 (3.82 to 12.44), and for Guillain-Barré syndrome was 3.53 (1.83 to 6.77). Transverse myelitis was rare (<5 events in all vaccinated cohorts) and could not be analysed.

CONCLUSIONS

No safety signal was observed between covid-19 vaccines and the immune mediated neurological events of Bell's palsy, encephalomyelitis, Guillain-Barré syndrome, and transverse myelitis. An increased risk of Bell's palsy, encephalomyelitis, and Guillain-Barré syndrome was, however, observed for people with SARS-CoV-2 infection.

Incidence, Disability, and Mortality in Patients With Guillain-Barré Syndrome in Korea: A Nationwide Population-Based Study

BACKGROUND AND PURPOSE

This study aimed to identify the epidemiological features of Guillain-Barré syndrome (GBS) in the Korean population.

METHODS

Patients with GBS were defined as those who were hospitalized with a primary diagnostic code of G61.0 on the Korean Classification of Disease in a department of neurology, rehabilitation medicine, or pediatrics. We evaluated the incidence and prevalence of GBS as well as physical disability, mortality, and cause of death in patients with GBS from 2002 to 2018 in the Korean population using the Korean National Health Insurance Service database.

RESULTS

We identified 11,146 patients with GBS. The ratio of males to females was 1.48. The age-adjusted incidence rate per 100,000 persons increased steadily from 0.84 in 2002 to 1.68 in 2018, as did the age-adjusted prevalence rate per 100,000 persons, from 0.77 to 15.62. The incidence and prevalence of GBS increased with age, peaking at 70-79 years. Among 10,114 patients without physical disability at the time of GBS being diagnosed, 502 (5.0%) patients had moderate disability and 526 (5.2%) had severe disability by the end of the study period. A total of 1,221 (11.0%) patients with GBS died during the mean follow-up period of 17 years (2002-2019). There were 144 (1.3%) in-hospital deaths.

CONCLUSIONS

This was the first nationwide epidemiological study of patients with GBS covering the entire population including patients of all ages in the Republic of Korea. We have revealed the seasonality of admissions, disability, and long-term mortality rates in patients with GBS.

COVID-19 and neurologic manifestations: a synthesis from the child neurologist's corner

BACKGROUND

Since December 2019, the SARS-CoV-2 virus has been a global health issue. The main clinical presentation of this virus is a flu-like disease; however, patients with diverse neurologic manifestations have also been reported. In this review, we attempt to summarize, discuss and update the knowledge of the neurologic manifestations in the pediatric population affected by SARS-CoV-2 infection and the pandemic's effects in children with neurologic diseases.

DATA SOURCES

This review analyzes studies found on the PubMed database using the following keywords: Neurologic manifestations COVID-19, Neurological COVID-19, coronavirus, SARS-CoV-2, pediatric COVID-19, COVID-19 in children, MIS-C, Pediatric Inflammatory Multisystem Syndrome, Guillain Barré Syndrome, Stroke, ADEM, and Anti-NMDA encephalitis. All studies cited were published between 2004 and 2022, and represent the most relevant articles in the field. The World Health Organization COVID-19 online dashboard was assessed to obtain updated epidemiological data.

RESULTS

The most common neurologic symptoms in the pediatric population are headache, seizures, encephalopathy, and muscle weakness. These can be present during COVID-19 or weeks after recovering from it. Children who presented with multi-system inflammatory syndrome had a higher incidence of neurologic manifestations, which conferred a greater risk of morbidity and mortality. Several neuro-pathophysiological mechanisms have been proposed, including direct virus invasion, hyper-inflammatory reactions, multi-systemic failure, prothrombotic states, and immune-mediated processes. On the other hand, the COVID-19 pandemic has affected patients with neurologic diseases, making it challenging to access controls, treatment, and therapies.

CONCLUSIONS

Various neurologic manifestations have been associated with children's SARS-CoV-2 infection. It is important to identify and give them proper and opportune treatment because they can be potentially grave and life-threatening; some can lead to long-lasting sequelae. Different neuro-pathophysiological mechanisms have been proposed, however, a causal relationship between SARS-CoV-2 infection and neurologic manifestations remains to be proven. Patients with neurologic diseases are especially affected by COVID-19, not only by the disease itself but also by its complications and pandemic management measures.

Vaccination in pediatric acquired inflammatory immune-mediated neuromuscular disorders

AIM

To analyse literature data on vaccine related induction, worsening of the disease and disease reccurrences as well as vaccine safety and efficacy among pediatric patients with acquired inflammatory immune-mediated neuromuscular disorders (NMD).

METHODS

Medline, Pub Med and Scopus database search from 1975 to 2020 focused on pediatric age was conducted including peer reviews, meta analyses and epidemiological studies on vaccination and Guillain-Barré syndrome (GBS), Bell's palsy, optic neuritis (ON), myasthenia gravis (MG), chronic inflammatory demyelinating polyneuropathy (CIDP) and immune-mediated inflammatory myopathy (IM).

RESULTS AND CONCLUSION

s: There are no strong evidence supporting relationship between vaccination with different pediatric vaccines and development of first episodes or reccurrences of GBS, Bell's palsy, optic neuritis (ON), juvenile MG, CIDP, and IM. The vaccination and revaccination with inactivated vaccines is considered safe in children with medical history of GBS, Bell's palsy, ON, MG and IM. Caution when immunization against influenza, quadrivalent conjugated meningococcal vaccine (MCV4) and pneumococcal disease and avoiding tetanus toxoid immunization in CIDP patients is suggested. Patients with immune mediated acquired NMD should be vaccinated with live vaccines before the initiation of immunosupressive treatment. Immunosuppressed patients with low protective antibody titers should be considered for revaccination.

AstraZeneca COVID-19 vaccine and Guillain- Barré Syndrome in Tasmania: A causal link?

The emergence of the coronavirus 2019 (COVID-19) pandemic has presented an unprecedented global challenge. Vaccines against COVID have been developed to date. Covid-19 has been linked with the development of Guillain-Barre Syndrome (GBS), a rare immune-mediated demyelinating neuropathy. We report three cases of Guillain-Barre Syndrome and one case of Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), presenting to a Tasmanian hospital, and review 15 other reported cases and discuss likely immunopathology. Nearly all reported cases of post-COVID-19 vacciation inflammatory demyelinating polyneuropathy are linked to AstraZeneca vaccination and a variant with bifacial weakness is the most reported form of GBS globally.

Analysis of adverse events following immunization in Zhejiang, China, 2019: a retrospective cross-sectional study based on the passive surveillance system

Objectives: This study summarizes passive surveillance data for adverse events following immunization (AEFI) in Zhejiang province.Methods: The AEFI reports and number of doses on all vaccines used were extracted from the national AEFI surveillance system and the immunization information system of Zhejiang province (ZJIIS). Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, vaccine types, and reaction categories.Results: A total of 13,079 AEFI records were reported and 23,091,401 vaccine doses were administered, with a reporting rate of 56.64/100,000 doses for AEFI. The highest reporting rate of AEFI was observed among the infants <1 year of age (108.61/100,000 doses) and the lowest rate was observed among recipients aged ≥60 years. Most of the AEFI reports were vaccine product-related reactions (48.81/100,000 doses), and the lowest was vaccination errors (0.02/100,000 doses). The most frequently reported individual vaccine was DTP and Hib combined vaccine, with a reporting rate of 426.62/100,000 doses. The most frequently reported AEFI was fever/redness/induration (48.82/100,000 doses).Conclusion: Our findings illustrated the high level of vaccine safety since the majority of those reported were not serious, or coincidentally associated with vaccination. Furthermore, the national AEFI surveillance system should be continuously used as a surveillance tool for monitoring of AEFI.

Seasonality in the incidence of anti-GQ1b antibody syndrome-A territory-wide study

AIMS

To investigate any seasonality in the incidence of anti-GQ1b antibody syndrome (AGS).

METHODS

We conducted a retrospective observational study in all hospitalized patients in local public hospitals from January 2013 to December 2018. AGS was defined by hospitalized patients with positive serum anti-GQ1b IgG, presumably encompassing Miller-Fisher syndrome, Bickerstaff brainstem encephalitis and Guillain-Barré syndrome (GBS) variants. GBS cases were retrieved from the computerized database by diagnostic label. Campylobacter jejuni infection (CJI) injection was identified by positive stool culture. Monthly incidence rates of AGS, GBS and CJI were calculated. Poisson and negative binomial regression models with long-term time trend were fitted to characterize the seasonal pattern.

RESULTS

A total of 237, 572 and 2434 cases of AGS, GBS and CJI were identified, respectively, in a population of 7.3 million. The annual incidence rate of AGS was 0.54 per 100,000 person-years. AGS was demonstrated to have an annual peak in the spring season, from March to April, which was congruent with that of GBS and slightly lagged the annual peak of CJI from February to March (likelihood ratio tests all p < .001 for the seasonal terms).

CONCLUSION

The incidence of AGS peaks in springtime, which is congruent with that of GBS and lags around one month after that of CJI. We demonstrated that AGS has a clear seasonality in occurrence.

Analysis of the adverse events following immunization with inactivated quadrivalent influenza vaccine from 2018 to 2020 in Zhejiang province, with a comparison to trivalent influenza vaccine

OBJECTIVES

To summarize reports to the national adverse event following immunization surveillance system (NAEFISS) following inactivated quadrivalent influenza vaccine (QIV) in Zhejiang province from 2018 to 2020.

METHODS

We analyzed adverse events following immunization (AEFI) reports following QIV, with a comparison, with the AEFI reports following inactivated trivalent influenza vaccine (TIV). Reporting rates of AEFI were calculated by age, severity of AEFI, categories of AEFI, and reaction categories. The data mining algorithm used in this study was reporting odds ratio (ROR). A value of ROR‑1.96SE >1 (standard error [SE]) was considered as positive signal. These reporting rates between vaccine types were compared through chi-square tests.

RESULTS

NAEFISS received 514 AEFI reports following QIV and 536 reports following TIV, with a reporting rate of 13.66/100,000 100,000 doses/100,000 doses (χ² = 7.11, P> .05). Of the 514 reports following QIV, 410 were vaccine product-related reactions and 51 were severe AEFI. Fever/redness/induration was the most frequent clinical diagnosis of the QIV AEFI, with a reporting rate of 12.42/100,000 doses in the age group of 3-17 years, and 12.44/100,000 doses in the age group of ≥18 years. The positive signal of QIV AEFI was observed for the allergic rash and asthma/wheezing.

CONCLUSION

The present analysis did not identify any new/unexpected safety concerns. We suggested that NAEFISS continue to monitor the safety of QIV.

Acute and chronic inflammatory neuropathies and COVID-19 vaccines: Practical recommendations from the task force of the Italian Peripheral Nervous System Association (ASNP)

BACKGROUND AND AIMS

To develop recommendations for vaccination for coronavirus-19 (COVID-19) in patients with inflammatory neuropathies.

METHODS

Key questions were formulated in order to perform a literature review on the safety and efficacy of vaccines in patients with inflammatory neuropathies. Based on the best evidence and expert opinion, a list of recommendations was formulated to inform decision on vaccination for COVID-19 in patients with inflammatory neuropathies and increase adherence to vaccination programmes.

RESULTS

Recommendations addressing safety and efficacy of vaccination in patients with inflammatory neuropathies were formulated. No data are currently available on the safety and efficacy of COVID-19 vaccines in patients with inflammatory neuropathies or other immune-mediated conditions. There is only sparse data on the safety of previous available vaccines in patients with inflammatory neuropathies, but studies on other autoimmune disorders indicate that these are safe and mostly efficacious. Patients with inflammatory neuropathies might be at increased risk for severe illness from COVID-19.

INTERPRETATION

Patients with inflammatory neuropathies should be encouraged to adhere to the vaccination campaign for COVID-19. These recommendations provide guidance on the management of vaccinations for COVID-19 in patients with inflammatory neuropathies. More research is needed regarding the safety and efficacy of vaccination in patients with inflammatory neuropathies and other immune conditions.

Prediction of post-vaccination Guillain-Barré syndrome using data from a passive surveillance system

Purpose

Severe adverse events (AEs), such as Guillain‐Barré syndrome (GBS) occur rarely after influenza vaccination. We identify highly associated AEs with GBS and develop prediction models for GBS using the US Vaccine Adverse Event Reporting System (VAERS) reports following trivalent influenza vaccination (FLU3).

Methods

This study analyzed 80 059 reports from the US VAERS between 1990 and 2017. Several AEs were identified as highly associated with GBS and were used to develop the prediction model. Some common and mild AEs that were suspected to be underreported when GBS occurred simultaneously were removed from the final model. The analyses were validated using European influenza vaccine AEs data from EudraVigilance.

Results

Of the 80 059 reports, 1185 (1.5%) were annotated as GBS related. Twenty‐four AEs were identified as having strong association with GBS. The full prediction model, using age, sex, and all 24 AEs achieved an area under the receiver operating characteristic (ROC) curve (AUC) of 85.4% (90% CI: [83.8%, 86.9%]). After excluding the nine (e.g., pruritus, rash, injection site pain) likely underreported AEs, the final AUC became 77.5% (90% CI: [75.5%, 79.6%]). Two hundred and one (0.25%) reports were predicted as of high risk of GBS (predicted probability >25%) and 84 actually developed GBS.

Conclusion

The prediction performance demonstrated the potential of developing risk‐prediction models utilizing the VAERS cohort. Excluding the likely underreported AEs sacrificed some prediction power but made the model more interpretable and feasible. The high absolute risk of even a small number of AE combinations suggests the promise of GBS prediction within the VAERS dataset.

Incidence of Guillain-Barré Syndrome is not Associated with Influenza Vaccination in the Elderly

We aimed to analyze the incidence of Guillain-Barré syndrome (GBS) and its association with influenza vaccination (IV) in the elderly population. This study included 2470 patients hospitalized with GBS (G61.0) between 2014 and 2016 based on the Korean National Health Insurance Service (NHIS) claims data. We reviewed every medical claim in the 42 days preceding GBS diagnosis looking for precedent causes of GBS. To assess the relationship between IV and the development of GBS, data from the NHIS and the National Vaccination Registry were combined and analyzed. Using a self-controlled case series (SCCS) approach, we calculated the incidence rate ratio by setting the risk period as 42 days following vaccination. The annual background incidence of GBS was estimated at 4.15 per 100,000 persons. More than half of the patients with newly developed GBS had a previous infection or surgery. The incidence of GBS within 42 days of IV was estimated at 0.32 per 100,000 vaccinated persons. SCCS analysis showed that the risk of GBS was not significantly higher. While GBS can potentially develop from various infections, no association was found between GBS and IV. These results will contribute to developing an evidence-based vaccine policy that includes a clear causality assessment of adverse events.

Is an Increased Risk of Developing Guillain-Barré Syndrome Associated with Seasonal Influenza Vaccination? A Systematic Review and Meta-Analysis

While the weight of epidemiological evidence does not support a causal link with influenza vaccination evaluated over the last 30 years, Guillain–Barré syndrome (GBS) has been considered a vaccine-associated adverse event of interest since 1976. To investigate the existence of GBS risk after vaccination against seasonal influenza, a systematic review and meta-analysis have been conducted based on 22 eligible epidemiological studies from 1981 to 2019 reporting 26 effect sizes (ESs) in different influenza seasons. The primary result of our meta-analysis pointed to no risk of vaccine-associated GBS, as documented by a pooled ES of 1.15 (95% CI: 0.97–1.35). Conversely, an obvious high risk of GBS was observed in patients with previous influenza-like illness (ILI), as demonstrated by a pooled ES of 9.6 (95% CI: 4.0–23.0) resulting from a supplementary analysis. While the meta-analysis did not confirm the putative risk of vaccine-associated GBS suggested by many epidemiological studies, vaccination against seasonal influenza reduced the risk of developing ILI-associated GBS by about 88%. However, to obtain strong evidence, more epidemiological studies are warranted to establish a possible coincidence between vaccination and ILI prior to GBS onset.

Seasonal influenza vaccine and Guillain-Barré syndrome: A self-controlled case series study

OBJECTIVE

To evaluate the risk of Guillain-Barré syndrome (GBS) following seasonal influenza vaccination based on French nationwide data.

METHODS

All cases of GBS occurring in metropolitan France between September 1 and March 31 from 2010 to 2014 were identified from the French national health data system. Data were analyzed according to the self-controlled case series method. The risk period started 1 day after the patient received vaccine (D1) until 42 days after vaccination (D42). The incidence of GBS during this risk period was compared to that of the control period (D43-March 31). The incidence rate ratio (IRR) was estimated after adjusting for seasonality and presence or not of acute infections.

RESULTS

Between September and March, of the 2010/2011 to 2013/2014 influenza vaccination seasons, 3,523 cases of GBS occurred in metropolitan France and were included in the study. Among them, 15% (527 patients) had received influenza vaccination. A total of 140 patients developed GBS during the 42 days following influenza vaccination. The crude risk of developing GBS was not significantly increased during the 42 days following influenza vaccination (IRR, 1.02; 95% confidence interval [CI], 0.83-1.25; p = 0.85). This result remained nonsignificant after adjustment for calendar months and the incidence of acute gastrointestinal and respiratory tract infections (IRR, 1.10; 95% CI, 0.89-1.37; p = 0.38). In contrast, the risk of GBS was fourfold higher after acute respiratory tract infection (IRR, 3.89; 95% CI, 3.52-4.30; p < 0.0001) or gastrointestinal infection (IRR, 3.64; 95% CI, 3.01-4.40; p < 0.0001).

CONCLUSIONS

No association between seasonal influenza vaccination and GBS was shown during the 42 days following vaccination.

Do Vaccines Trigger Neurological Diseases? Epidemiological Evaluation of Vaccination and Neurological Diseases Using Examples of Multiple Sclerosis, Guillain-Barré Syndrome and Narcolepsy

This article evaluates the epidemiological evidence for a relationship between vaccination and neurological disease, specifically multiple sclerosis, Guillain-Barré syndrome and narcolepsy. The statistical methods used to test vaccine safety hypotheses are described and the merits of different study designs evaluated; these include the cohort, case-control, case-coverage and the self-controlled case-series methods. For multiple sclerosis, the evidence does not support the hypothesized relationship with hepatitis B vaccine. For Guillain-Barré syndrome, the evidence suggests a small elevated risk after influenza vaccines, though considerably lower than after natural influenza infection, with no elevated risk after human papilloma virus vaccine. For narcolepsy, there is strong evidence of a causal association with one adjuvanted vaccine used in the 2009/10 influenza pandemic. Rapid investigation of vaccine safety concerns, however biologically implausible, is essential to maintain public and professional confidence in vaccination programmes.

Vaccines and the risk of Guillain-Barré syndrome

The role of vaccination in the development of Guillain-Barré syndrome (GBS) is controversial, although cases of GBS have been reported following a wide range of vaccines. A nested case-control study was conducted between January 2011 and December 2015 in three Chinese cities. Four controls were matched to a case by gender, age, address and index date. An independent expert committee validated the diagnoses of cases and controls according to the Brighton Collaboration GBS case definition. Data on vaccinations were obtained from computerized vaccination records. Causal relations were assessed by conditional logistic regression. 1056 cases of GBS and 4312 controls were included in the analyses. Among paediatric and adult population, adjusted ORs for GBS occurrence within 180 days following vaccination were 0.94 (95% CI 0.54-1.62) and 1.09 (95% CI 0.88-1.32), respectively. No increased risk of GBS was detected for vaccination against hepatitis B, influenza, hepatitis A, varicella, rabies, polio(live), diphtheria, pertuss(acellular), tetanusis, measles, mumps, rubella, Japanese Encephalitis, and meningitis vaccines. Adjusted ORs for the recurrence of GBS after vaccination among paediatric and adult population were 0.85 (95% CI 0.07-9.50) and 1.18 (95% CI 0.49-2.65), respectively. In this large retrospective study, we did not find evidence of an increased risk of GBS and its recurrence among either paediatric (≤ 18 years) or adult (> 18 years) individuals within the 180 days following vaccinations of any kind, including influenza vaccination.

Influenza Infections and Emergent Viral Infections in Intensive Care Unit

Critically ill patients are admitted to an intensive care unit (ICU) for multiple reasons. In this study, we aim to analyze the current evidence and findings associated with influenza and other emergent viral infections, namely, herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV), and cytomegalovirus (CMV).

Among medical conditions, community-acquired respiratory infections are the most frequent reason for ventilatory support in ICUs. Community-acquired pneumonia in a severe form including the need of invasive mechanical ventilation and/or vasopressors is associated with high mortality rates. However, after the pandemic that occurred in 2009 by H1N1 influenza, the number of cases being admitted to ICUs with viral infections is on the rise. Patients in whom an etiology would not have been identified in the past are currently being tested with more sensitive viral molecular diagnostic tools, and patients being admitted to ICUs have more preexisting medical conditions that can predispose to viral infections. Viral infections can trigger the dysregulation of the immune system by inducing a massive cytokine response. This cytokine storm can cause endothelial damage and dysfunction, deregulation of coagulation, and, consequently, alteration of microvascular permeability, tissue edema, and shock. In severe influenza, this vascular hyperpermeability can lead to acute lung injury, multiorgan failure, and encephalopathy. In immunocompetent patients, the most common viral infections are respiratory, and influenza should be considered in patients with severe respiratory failure being admitted to ICU. Seasonality and coinfection are two important features when considering influenza as a pathogen in critically ill patients.

Herpesviridae (HSV, CMV, and EBV) may reactivate in ICU patients, and their reactivation is associated with morbidity/mortality. However, whether a specific treatment may impact on outcome remains to be determined.

Guillain-Barré syndrome and influenza vaccines: current evidence

OBJECTIVE

Guillain-Barré Syndrome (GBS) as a consequence of influenza vaccination is a relevant topic, yet to be clarified, which raises concern both amongst health care personnel and the general population. Every study and pharmacovigilance system point to need of further research and the importance of continuous monitoring of safety regarding influenza vaccines. The aim of the present study is to investigate the publication of new data since the realisation of our meta-analysis of GBS and influenza vaccines (published in 2015).

METHODS

A systematic revision of PubMed, Embase, and Web of Knowledge (WOS) databases has been carried out. These report observational studies assessing GBS risk after the administration of influenza vaccines from May 2014 up to July 20th, 2017.

RESULTS

The research yielded 107 articles. Only three studies met established inclusion criteria and referred to an estimation GBS risk after some influenza vaccine. Two studies investigated GBS risk by the pandemic A/H1N1 vaccine, while only one looked into season vaccines.

CONCLUSIONS

The present systematic review, conducted after the publication of our previous meta-analysis, seems to confirm its previous results. Therefore, GBS should be considered an infrequent adverse effect of influenza vaccination, which should not negatively influence its acceptance. Unfortunately, very few of the systematically surveyed studies meeting inclusion criteria. This fact sharply contrasts with the current consensus as to the need of continuously monitoring the safety of influenza vaccines.

Guillain-Barré syndrome and related diseases after influenza virus infection

Objective

We examined the clinical and serologic features of Guillain-Barré syndrome (GBS)-related diseases (GBSRDs), including GBS, Fisher syndrome (FS), and Bickerstaff brainstem encephalitis (BBE), after influenza virus infection (GBSRD-I) to reveal potential underlying autoimmune mechanisms.

Methods

We retrospectively investigated the presence of antiglycolipid antibodies against 11 glycolipids and the clinical features of 63 patients with GBSRD-I. Autoantibody profiles and clinical features were compared with those of 82 patients with GBSRDs after Campylobacter jejuni infection (GBSRD-C).

Results

The anti-GQ1b seropositivity rate was significantly higher, whereas the GM1 and GD1a seropositivity rates were significantly lower in GBSRD-I compared with GBSRD-C. Anti-GQ1b and anti-GT1a were the most frequently detected antiglycolipid antibodies in GBSRD-I (both 15/63, 24%). Consequently, FS was more frequent in GBSRD-I than GBSRD-C (22% vs 9%, p < 0.05). In addition, as for GBS, cranial nerve deficits, sensory disturbances, and ataxia were more frequent in the cases after influenza infection (GBS-I) than in those after C. jejuni infection (GBS-C) (46% vs 15%, 75% vs 46%, and 29% vs 4%, respectively; all p < 0.01). Nerve conduction studies revealed acute inflammatory demyelinating polyneuropathy (AIDP) in 60% of patients with GBS-I but only 25% of patients with GBS-C (p < 0.01).

Conclusions

Anti-GQ1b antibodies are the most frequently detected antibodies in GBSRD-I. Compared with GBS-C, GBS-I is characterized by AIDP predominance and frequent presence of cranial nerve involvement and ataxia.

Surveillance for Guillain-Barré syndrome after influenza vaccination among U.S. Medicare beneficiaries during the 2017-2018 season

BACKGROUND

The U.S. Food and Drug Administration and the Centers for Medicare & Medicaid Services have been actively monitoring the risk of Guillain-Barré syndrome (GBS) following influenza vaccination among Fee-for-Service (FFS) Medicare beneficiaries every season since 2008. We present our evaluation of the GBS risk following influenza vaccinations during the 2017-2018 season.

METHODS

We implemented a multilayered approach to active safety surveillance that included near real-time surveillance early in the season, comparing GBS rates post-vaccination during the 2017-2018 season with rates from five prior seasons using the Updating Sequential Probability Ratio Test (USPRT), and end-of-season self-controlled risk interval (SCRI) analyses.

RESULTS

We identified approximately 16 million influenza vaccinations. The near real-time surveillance did not signal for a potential 2.5-fold increased GBS risk either in days 8-21 or 1-42 post-influenza vaccination. In the SCRI analyses, we did not detect statistically significant increased GBS risks among influenza-vaccinated Medicare beneficiaries ≥65 years for either the 8-21 or 1-42-day risk windows for all seasonal vaccines combined, high-dose vaccine, or standard-dose vaccines; we did detect an increased GBS risk in days 8-21 post-vaccination for individuals vaccinated with the adjuvanted vaccine (OR: 3.75; 95% CI: 1.01, 13.96), although this finding was not statistically significant after multiplicity adjustment (p = 0.146).

CONCLUSIONS

Our multilayered surveillance approach-which allows for early detection of elevated GBS risk and provides reliable end-of-season SCRI estimates of effect size-did not identify an increased GBS risk following 2017-2018 influenza vaccinations. The slightly increased GBS risk with the adjuvanted vaccine, which was not statistically significant following multiplicity adjustment, is consistent with the package inserts of all U.S.-licensed influenza vaccines, which warn of a potential low increased GBS risk. The benefits of influenza vaccines in preventing morbidity and mortality heavily outweigh this potential risk.

Pulmonary complications of influenza infection: a targeted narrative review

Severe influenza infection represents a leading cause of global morbidity and mortality. Several clinical syndromes that involve a number of organs may be associated with Influenza infection. However, lower respiratory complications remain the most common and serious sequel of influenza infection. These include influenza pneumonia, superinfection with bacteria and fungi, exacerbation of underlying lung disease and ARDS. This review analyzes the available literature on the epidemiology and clinical considerations of these conditions. It also provides an overview of the effects of type of influenza, antiviral therapy, vaccination and other therapies on the outcome of these complications.

Systematic review of factors associated with the development of Guillain-Barré syndrome 2007-2017: what has changed?

OBJECTIVE

The objective of this study was to describe the factors associated with the development of Guillain-Barré syndrome, both infectious and non-infectious, during and after the A(H1N1) influenza pandemic in 2009 and the recent Zika virus epidemic in the Americas.

METHOD

Systematic review of literature on factors associated with the development of the Guillain-Barré syndrome published between 2007 and 2017 listed in EBSCO, MEDLINE and LILACS databases. The quality of the studies was evaluated using the Newcastle Ottawa Scale.

RESULTS

Thirty-four articles met inclusion criteria and were selected for analysis. Their quality was considered good in relation to most of the items evaluated. Many aetiological agents had the results of association with Guillain-Barré syndrome, among them Campylobacter jejuni, influenza vaccine - both pandemic and seasonal vaccines, respiratory infection, gastrointestinal infection among others. The aetiological agents found are, in most part, the same reported prior to the study period. The association with surgeries, chikungunya virus (CHIKV), Zika virus and quadrivalent human papillomavirus vaccine stand out as new aetiological agents in the list of the various possible agents that trigger Guillain-Barré syndrome reported in the study period. There were no Brazilian studies identified during this period.

CONCLUSIONS

The results of the review reaffirmed C. jejuni as the major trigger of GBS, whereas the association of influenza vaccines and GBS is less clear; Zika virus infection in association with GBS was found in only one study.

HPV vaccine and autoimmune diseases: systematic review and meta-analysis of the literature

BACKGROUND

In the literature conflicting opinions are detectable on the onset of adverse events as autoimmune disease post HPV vaccine and often case reports describes the onset of one of these events, but don't emerge a clear relationship and we don't have data to support it.

METHODS

We carried out a systematic review to identify all scientific publications dealing with the correlation between vaccine anti-papillomavirus and new onset of autoimmune diseases. We searched the main scientific databases (PubMed, Sciverse Scopus, Web of knowledge and Cochrane Central Register of Controlled Clinical Trials) for the following search terms: "vaccine"; "anti-papillomavirus"; "autoimmune"; "disease"; "disorder". To evaluate the safety of HPV vaccines, the dichotomous data on the number of subjects experiencing an autoimmune disorder in the study vaccine group and the placebo group were extracted from each study with subsequent determination of the risk ratios and their 95% confidence intervals. We combined data statistically using a random effects model.

RESULTS

We conduct a meta-analysis on six studies on bivalent and quadrivalent HPV vaccine. The total number of subjects included in the meta-analysis comprised 243,289 in the vaccine group and 248,820 in control groups. Four of the six trials had a Jadad score of 3 or 4 indicating an adequate trial quality. The most frequent autoimmune disease observed across the six studies were musculoskeletal,CNS conditions and endocrinological conditions . The results of the meta-analysis demonstrated no correlation between autoimmune disorders and HPV vaccines (pooled OR 1.038, 95% CI 0.689-1.562).

CONCLUSIONS

No correlation was identified for bivalent and quadrivalent HPV vaccines. It's therefore essential to correctly inform the general population in order to try to increase both Italian and international vaccination coverage.

Vaccine-preventable diseases, vaccines and Guillain-Barre' syndrome

Guillain-Barré syndrome (GBS) is an acute, immune-mediated polyradiculoneuropathy. Infections and vaccines have been hypothesized to play a role in triggering GBS development. These beliefs can play a role in reducing vaccination coverage. In this report, data concerning this hypothesis are discussed. It is shown that an association between vaccine administration and GBS has never been proven for most of debated vaccines, although it cannot be definitively excluded. The only exception is the influenza vaccine, at least for the preparation used in 1976. For some vaccines, such as measles/mumps/rubella, human papillomavirus, tetravalent conjugated meningococcal vaccine, and influenza, the debate between supporters and opponents of vaccination remains robust and perception of vaccines' low safety remains a barrier to achieving adequate vaccination coverage. Less than 1 case of GBS per million immunized persons might occur for these vaccines. However, in some casesimmunization actually reduces the risk of GBS development. In addition, the benefits of vaccination are clearly demonstrated by the eradication or enormous decline in the incidence of many vaccine-preventable diseases. These data highlight that the hypothesized risks of adverse events, such as GBS, cannot be considered a valid reason to avoid the administration of currently recommended vaccines.

The hidden burden of influenza: A review of the extra-pulmonary complications of influenza infection

Severe influenza infection represents a leading cause of global morbidity and mortality. Although influenza is primarily considered a viral infection that results in pathology limited to the respiratory system, clinical reports suggest that influenza infection is frequently associated with a number of clinical syndromes that involve organ systems outside the respiratory tract. A comprehensive MEDLINE literature review of articles pertaining to extra‐pulmonary complications of influenza infection, using organ‐specific search terms, yielded 218 articles including case reports, epidemiologic investigations, and autopsy studies that were reviewed to determine the clinical involvement of other organs. The most frequently described clinical entities were viral myocarditis and viral encephalitis. Recognition of these extra‐pulmonary complications is critical to determining the true burden of influenza infection and initiating organ‐specific supportive care.

Absence of association between Guillain-Barré syndrome hospitalizations and HPV-vaccine

BACKGROUND

In 2008, a school-based human papilloma virus (HPV) vaccination program was implemented in the province of Québec. Grade 4 girls (9-10 years old) are routinely vaccinated and grade 9 to 12 girls (14-17 years old) were eligible for the catch-up vaccination. Vaccine coverage of the targeted cohorts was estimated at 76-81%. To assess if HPV vaccination is associated with an increase in GBS hospitalisation, we compared the hospitalization rates of GBS in HPV vaccination targeted and non-targeted groups.

METHODS

Hospital discharge records with a GBS code as the main diagnosis during the 1999-2014 period were retrieved. Incidence rates according to program eligibility were computed and adjusted relative risk in the targeted groups was estimated by Poisson regression.

RESULTS

The overall incidence rate in the 7 to 17 year-olds was 0.73/100,000 p-y. There was no increase in GBS incidence in HPV vaccination targeted groups (adjusted IRR = 0.81, 95%CI: 0.29-2.26).

CONCLUSION

No signal of increase GBS hospitalisation incidence in the HPV-vaccine targeted group was detected in the hospitalisation database.

Human papillomavirus vaccination and risk of autoimmune diseases: A large cohort study of over 2million young girls in France

BACKGROUND

Whether human papillomavirus (HPV) vaccination could induce or trigger autoimmune diseases (AID) has been questioned, and potentially contributes to low immunization coverage in France. This study evaluated the association between HPV vaccination and the risk of AID using routinely collected data sources.

METHODS

All girls aged 13-16years between 2008 and 2012, covered by the general health insurance scheme and without history of HPV vaccination or AID, were included and followed using French nationwide databases. Fourteen neurological, rheumatological, haematological, gastrointestinal or endocrine AID, were identified from ICD-10 codes allocated to hospital stays and long-term illnesses or by marker drugs. Their incidence was compared between girls exposed and non-exposed to HPV vaccination, using a Cox model adjusted for inclusion year, geographic area, socio-economic indicators, healthcare use level and other immunizations.

RESULTS

Among 2,252,716 girls, 37% received HPV vaccine and 4,096 AID occurred during a mean follow-up time of 33months. The incidence of AID was not increased after exposure to HPV vaccination, except for Guillain-Barré syndrome (GBS) (incidence rate of 1.4 among exposed [20 cases] versus 0.4 per 100,000 PY among unexposed [23 cases]; adjusted HR: 3.78 [1.79-7.98]). This association persisted across numerous sensitivity analyses and was particularly marked in the first months following vaccination. Under the hypothesis of a causal relationship, this would result in 1-2 GBS cases attributable to HPV vaccine per 100,000 girls vaccinated.

CONCLUSIONS

Our study provides reassuring results regarding the risk of AID after HPV vaccination, but an apparently increased risk of GBS was detected. Further studies are warranted to confirm this finding.

Vaccination and autoimmune diseases: is prevention of adverse health effects on the horizon?

Autoimmune diseases, including multiple sclerosis and type 1 diabetes mellitus, affect about 5% of the worldwide population. In the last decade, reports have accumulated on various autoimmune disorders, such as idiopathic thrombocytopenia purpura, myopericarditis, primary ovarian failure, and systemic lupus erythematosus (SLE), following vaccination. In this review, we discuss the possible underlying mechanisms of autoimmune reactions following vaccinations and review cases of autoimmune diseases that have been correlated with vaccination. Molecular mimicry and bystander activation are reported as possible mechanisms by which vaccines can cause autoimmune reactions. The individuals who might be susceptible to develop these reactions could be especially not only those with previous post-vaccination phenomena and those with allergies but also in individuals who are prone to develop autoimmune diseases, such as those with a family history of autoimmunity or with known autoantibodies, and the genetic predisposed individuals. Further research is encouraged into the direct associations between vaccines and autoimmune conditions, and the biological mechanisms behind them.

No increased risk of Guillain-Barré syndrome after human papilloma virus vaccine: A self-controlled case-series study in England

OBJECTIVE

To investigate the risk of Guillain-Barré syndrome (GBS) after human papilloma virus (HPV) vaccine given to 12-18year old girls in England.

METHODS

Hospital Episode Statistics (HES) were searched using data to March 2016 to identify incident cases of GBS in female patients aged from 11 to 20years eligible to have received the HPV vaccine since its introduction as a 3 dose schedule in September 2008. Diagnosis was confirmed by the case's general practitioner (GP) who also provided HPV vaccination dates. The risk of admission within 3months (primary risk window) 6 and 12months of any dose was assessed using the self-controlled case-series (SCCS) method in vaccinated girls with age, season and time-period adjustment. The risk before and after the change in 2012 from bivalent vaccine to quadrivalent vaccine was also assessed.

RESULTS

A total 244 episodes were initially identified which reduced to 101 episodes in 100 girls when just including cases where the GP could be contacted, at least one vaccine dose was given, and GBS was confirmed or classed as probable. Nine, 14 and 24GBS admissions occurred within 3, 6, 12months of a dose respectively. The relative incidence (RI) for the 3month risk period was 1.04 (95% confidence interval 0.47-2.28), for the 6month period 0.83 (0.41-1.69) and for the 12month period 1.10 (0.57-2.14). When restricting to 79 confirmed cases the RI in the 3month risk period was 1.26 (0.55-2.92) and the RI 1.61 (0.39-6.54) for quadrivalent vaccine compared to 0.84 (0.30-2.34) for bivalent.

CONCLUSION

We found no evidence of an increased risk of GBS following HPV vaccination in England and, based on the upper end of the 95% CI for the RI and the number of HPV vaccine doses given in England, can exclude a risk of about 1 per million doses.

Influenza

Influenza is one of the commonest infections in human populations, and causing substantial morbidity and mortality globally. The influenza virus is divided into different types and subtypes, three of which are currently circulating widely in humans: influenza A(H3N2) and influenza B. The virus undergoes constant evolution, leading to annual seasonal winter epidemics in temperate countries and necessitating annual updates to the vaccine. Rarely, completely new influenza viruses can emerge in human populations, giving rise to influenza pandemics. Children aged <5 years (especially those <2 years) and those with underlying illness such as cardiac, respiratory and severe neurologic disease have an increased risk of severe outcomes associated with influenza. Pregnant women have an increased risk of severe influenza. Complications may involve the respiratory tract (e.g. otitis media or pneumonia) or, less commonly, other organ systems (e.g. encephalitis or myocarditis). Specific antiviral treatment should be offered as soon as possible for hospitalized children with presumed or confirmed influenza and for influenza of any severity for children at high risk of severe complications of influenza without waiting for laboratory confirmation. Antiviral treatment is usually not warranted for uncomplicated influenza as this is usually self-limiting. Annual influenza vaccination should be offered to all individuals at increased risk for complications of influenza. Vaccine cannot be given to children aged <6 months but maternal influenza immunization during pregnancy is recommended and can confer protection to the young infant.

The safety of influenza vaccines in children: An Institute for Vaccine Safety white paper

Most influenza vaccines are generally safe, but influenza vaccines can cause rare serious adverse events. Some adverse events, such as fever and febrile seizures, are more common in children than adults. There can be differences in the safety of vaccines in different populations due to underlying differences in genetic predisposition to the adverse event. Live attenuated vaccines have not been studied adequately in children under 2 years of age to determine the risks of adverse events; more studies are needed to address this and several other priority safety issues with all influenza vaccines in children. All vaccines intended for use in children require safety testing in the target age group, especially in young children. Safety of one influenza vaccine in children should not be extrapolated to assumed safety of all influenza vaccines in children. The low rates of adverse events from influenza vaccines should not be a deterrent to the use of influenza vaccines because of the overwhelming evidence of the burden of disease due to influenza in children.

Prevention and Control of Seasonal Influenza with Vaccines

This report updates the 2015-16 recommendations of the Advisory Committee on Immunization Practices (ACIP) regarding the use of seasonal influenza vaccines (Grohskopf LA, Sokolow LZ, Olsen SJ, Bresee JS, Broder KR, Karron RA. Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices, United States, 2015-16 influenza season. MMWR Morb Mortal Wkly Rep 2015;64:818-25). Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. For the 2016-17 influenza season, inactivated influenza vaccines (IIVs) will be available in both trivalent (IIV3) and quadrivalent (IIV4) formulations. Recombinant influenza vaccine (RIV) will be available in a trivalent formulation (RIV3). In light of concerns regarding low effectiveness against influenza A(H1N1)pdm09 in the United States during the 2013-14 and 2015-16 seasons, for the 2016-17 season, ACIP makes the interim recommendation that live attenuated influenza vaccine (LAIV4) should not be used. Vaccine virus strains included in the 2016-17 U.S. trivalent influenza vaccines will be an A/California/7/2009 (H1N1)-like virus, an A/Hong Kong/4801/2014 (H3N2)-like virus, and a B/Brisbane/60/2008-like virus (Victoria lineage). Quadrivalent vaccines will include an additional influenza B virus strain, a B/Phuket/3073/2013-like virus (Yamagata lineage).Recommendations for use of different vaccine types and specific populations are discussed. A licensed, age-appropriate vaccine should be used. No preferential recommendation is made for one influenza vaccine product over another for persons for whom more than one licensed, recommended product is otherwise appropriate. This information is intended for vaccination providers, immunization program personnel, and public health personnel. Information in this report reflects discussions during public meetings of ACIP held on October 21, 2015; February 24, 2016; and June 22, 2016. These recommendations apply to all licensed influenza vaccines used within Food and Drug Administration-licensed indications, including those licensed after the publication date of this report. Updates and other information are available at CDC's influenza website (http://www.cdc.gov/flu). Vaccination and health care providers should check CDC's influenza website periodically for additional information.

Is real world evidence influencing practice? A systematic review of CPRD research in NICE guidances

BACKGROUND

There is currently limited evidence regarding the extent Real World Evidence (RWE) has directly impacted the health and social care systems. The aim of this review is to identify national guidelines or guidances published in England from 2000 onwards which have referenced studies using the governmental primary care data provider the Clinical Practice Research Datalink (CPRD).

METHODS

The methodology recommended by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was followed. Four databases were searched and documents of interest were identified through a search algorithm containing keywords relevant to CPRD. A search diary was maintained with the inclusion/exclusion decisions which were performed by two independent reviewers.

RESULTS

Twenty-five guidance documents were included in the final review (following screening and assessment for eligibility), referencing 43 different CPRD/GPRD studies, all published since 2007. The documents covered 12 disease areas, with the majority (N =7) relevant to diseases of the Central Nervous system (CNS). The 43 studies provided evidence of disease epidemiology, incidence/prevalence, pharmacoepidemiology, pharmacovigilance and health utilisation.

CONCLUSIONS

A slow uptake of RWE in clinical and therapeutic guidelines (as provided by UK governmental structures) was noticed. However, there seems to be an increasing trend in the use of healthcare system data to inform clinical practice, especially as the real world validity of clinical trials is being questioned. In order to accommodate this increasing demand and meet the paradigm shift expected, organisations need to work together to enable or improve data access, undertake translational and relevant research and establish sources of reliable evidence.

Guillain-Barré syndrome: causes, immunopathogenic mechanisms and treatment

INTRODUCTION

Guillain-Barré syndrome is a rare disease representing the most frequent cause of acute flaccid symmetrical weakness of the limbs and areflexia usually reaching its peak within a month. The etiology and pathogenesis remain largely enigmatic and the syndrome results in death or severe disability in 9-17% of cases despite immunotherapy. Areas covered: In terms of etiology, Guillain-Barré syndrome is linked to Campylobacter infection but less than 0.1% of infections result in the syndrome. In terms of pathogenesis, activated macrophages and T cells and serum antibodies against gangliosides are observed but their significance is unclear. Expert commentary: Guillain-Barré syndrome is a heterogeneous condition with numerous subtypes and recent data point towards the role of ganglioside epitopes by immunohistochemical methods. Ultimately, the syndrome results from a permissive genetic background on which environmental factors, including infections, vaccination and the influence of aging, lead to disease.

Guillain-Barré syndrome following the 2009 pandemic monovalent and seasonal trivalent influenza vaccination campaigns in Spain from 2009 to 2011: outcomes from active surveillance by a neurologist network, and records from a country-wide hospital discharge database

Background

Studies have shown a slight excess risk in Guillain-Barré syndrome (GBS) incidence associated with A(H1N1)pdm09 vaccination campaign and seasonal trivalent influenza vaccine immunisations in 2009–2010. We aimed to assess the incidence of GBS as a potential adverse effect of A(H1N1)pdm09 vaccination.

Methods

A neurologist-led network, active at the neurology departments of ten general hospitals serving an adult population of 4.68 million, conducted GBS surveillance in Spain in 2009–2011. The network, established in 1996, carried out a retrospective and a prospective study to estimate monthly alarm thresholds in GBS incidence and tested them in 1998–1999 in a pilot study. Such incidence thresholds additionally to observation of GBS cases with immunisation antecedent in the 42 days prior to clinical onset were taken as alarm signals for 2009–2011, since November 2009 onwards. For purpose of surveillance, in 2009 we updated both the available centres and the populations served by the network. We also did a retrospective countrywide review of hospital-discharged patients having ICD-9-CM code 357.0 (acute infective polyneuritis) as their principal diagnosis from January 2009 to December 2011.

Results

Among 141 confirmed of 148 notified cases of GBS or Miller-Fisher syndrome, Brighton 1–2 criteria in 96 %, not a single patient was identified with clinical onset during the 42-day time interval following A(H1N1)pdm09 vaccination. In contrast, seven cases were seen during a similar period after seasonal campaigns. Monthly incidence figures did not, however, exceed the upper 95 % CI limit of expected incidence. A retrospective countrywide review of the registry of hospital-discharged patients having ICD-9-CM code 357.0 (acute infective polyneuritis) as their principal diagnosis did not suggest higher admission rates in critical months across the period December 2009-February 2010.

Conclusions

Despite limited power and underlying reporting bias in 2010–2011, an increase in GBS incidence over background GBS, associated with A(H1N1)pdm09 monovalent or trivalent influenza immunisations, appears unlikely.

Adverse events following immunization: real causality and myths

INTRODUCTION

To assure the highest safety of immunization programs, detect adverse events following immunization (AEFIs), eliminate concerns, and reduce the risk of low vaccination coverage, authorities in industrialized countries have collected years of reports of suspected AEFIs and have systematically assessed their clinical importance.

AREAS COVERED

In this paper, the methods used to assess vaccine safety and the results obtained by the analysis of reports, studies, and meta-analyses are discussed.

EXPERT OPINION

Severe AEFIs are rare, and all evaluations of safety of vaccines recommended for both children and adults have demonstrated that the advantages of vaccines are always significantly higher than the problems that they cause, and there is no need to modify recommendations. However, the definition of AEFI is dependent on the vaccines themselves, complicating the definition of an AEFI and explaining why doubts and concerns have been raised. Presently, disease epidemiology data collected in healthy people and in subjects with underlying disease, general vaccine coverage, and the vaccination status of subjects with AEFIs are managed by many independent institutions. Only strict co-operation between these institutions will lead to the successful identification of AEFIs and to a reduction of the weight of anti-vaccine arguments.

T cell epitope redundancy: cross-conservation of the TCR face between pathogens and self and its implications for vaccines and autoimmunity

T cells are extensively trained on 'self' in the thymus and then move to the periphery, where they seek out and destroy infections and regulate immune response to self-antigens. T cell receptors (TCRs) on T cells' surface recognize T cell epitopes, short linear strings of amino acids presented by antigen-presenting cells. Some of these epitopes activate T effectors, while others activate regulatory T cells. It was recently discovered that T cell epitopes that are highly conserved on their TCR face with human genome sequences are often associated with T cells that regulate immune response. These TCR-cross-conserved or 'redundant epitopes' are more common in proteins found in pathogens that have co-evolved with humans than in other non-commensal pathogens. Epitope redundancy might be the link between pathogens and autoimmune disease. This article reviews recently published data and addresses epitope redundancy, the "elephant in the room" for vaccine developers and T cell immunologists.

Seasonal variation in Guillain-Barré syndrome: a systematic review, meta-analysis and Oxfordshire cohort study

INTRODUCTION

Evidence for seasonal variation in incidence and subtype of Guillain-Barré syndrome (GBS) is contradictory, but has implications for provision of neurological services and understanding pathogenesis.

METHODS

We searched PubMed and EMBASE between inception and January 2014, including all studies reporting seasonal incidence of GBS. We included a retrospective cohort study of patients with GBS at the John Radcliffe Hospital, Oxford 2001-2012 and determined the seasonal variation in GBS incidence and length of stay. The incidence rate ratio (IRR) for winter versus summer was pooled across studies by fixed and random effects meta-analysis weighted by inverse variance, stratified by geographical region, infectious prodrome and GBS subtype.

RESULTS

Across 9836 patients from 42 studies there was a 14% increased risk of GBS in winter versus summer (IRR=1.14, 1.02-1.27, p=0.020), with significant heterogeneity between studies (I(2)=77%, p<0.0001), including significant seasonal variation in Oxford (n=140; p=0.037) for winter versus summer (IRR=1.92, 1.18-3.11, p=0.004) but a non-significantly reduced length of stay for winter versus other seasons (15 vs 21 days, p=0.08). Across all studies, there was greater seasonal variation with respiratory prodrome (IRR=3.06, 1.84-5.11, p<0.0001) than diarrhoeal prodrome (IRR=1.10, 0.60-2.00, p=0.76) and a greater incidence in winter in Western countries (IRR=1.28), the Far East (IRR=1.20) and Middle East (IRR=1.12), with a lower incidence in the Indian subcontinent (IRR=0.86) and Latin America (IRR=0.75).

DISCUSSION

Incidence of GBS was greater in winter than summer, but this was not evident in all geographical regions. This is likely to be related to regional variation in prodromal illnesses.

Simulation study of the effect of influenza and influenza vaccination on risk of acquiring Guillain-Barré syndrome

Under typical conditions, such as influenza incidence rates of >5% and vaccine effectiveness >60%, vaccination reduced risk.

It is unclear whether seasonal influenza vaccination results in a net increase or decrease in the risk for Guillain-Barré syndrome (GBS). To assess the effect of seasonal influenza vaccination on the absolute risk of acquiring GBS, we used simulation models and published estimates of age- and sex-specific risks for GBS, influenza incidence, and vaccine effectiveness. For a hypothetical 45-year-old woman and 75-year-old man, excess GBS risk for influenza vaccination versus no vaccination was −0.36/1 million vaccinations (95% credible interval −1.22 to 0.28) and −0.42/1 million vaccinations (95% credible interval, –3.68 to 2.44), respectively. These numbers represent a small absolute reduction in GBS risk with vaccination. Under typical conditions (e.g. influenza incidence rates >5% and vaccine effectiveness >60%), vaccination reduced GBS risk. These findings should strengthen confidence in the safety of influenza vaccine and allow health professionals to better put GBS risk in context when discussing influenza vaccination with patients.