Hepatitis B vaccination and central nervous system demyelination: an immunological approach

Association between vaccination and the risk of central demyelination: results from a case-referent study

BACKGROUND

Few studies documented the potential association between vaccination and the risk of central demyelination (CD). Specifically, anti-hepatitis B and anti-human papillomavirus (HPV) vaccines have been the subject of distrust with regard to their implication to trigger CD.

METHODS

From a systematic national registry, patients with first signs of CD (cases) were identified and documented for their exposure to vaccination up to 24 months before the first signs occurred. This exposure was compared to that of a representative sample of general practice patients without a history of CD, randomly selected from a national registry (referents). CD cases were 2:1 matched on age, sex, index date (ID), and region of residence. Vaccines against influenza, HPV, hepatitis B and diphtheria-tetanus-pertussis-poliomyelitis-haemophilus (DTPPHae) were considered. Associations between vaccination and CD were assessed using multivariate conditional logistic regressions, controlled for confounding factors.

FINDINGS

564 CD cases were matched to 1,128 randomly selected referents (age range: 2-79 years old). Overall, 123 (22%) CD cases and 320 (28%) referents had received at least one vaccine within 24 months before ID. Adjusted odds ratios (ORs) for any vaccination were 0.69, 95% confidence interval (CI) [0.54-0.88] with respect to any CD first signs, 0.68 [0.51-0.90] for myelitis and 0.70 [0.42-1.17] for optic neuritis. Adjusted ORs for any CD first signs were 1.02 [0.71-1.47] for influenza vaccine (administered in 9.6% of cases and 10.4% of referents) and 0.72 [0.53-0.99] for DTPPHae vaccine (administered in 10.8% of cases and 14.5% of referents). Vaccines against hepatitis B and HPV were only administered in 1.1% and 1.2% of cases and in 2.9% and 3.2% of referents respectively, which statistically explained the point estimates < 1 (ORs of 0.39 [0.16-0.94] and of 0.32 [0.13-0.80]).

INTERPRETATION

No increased risk of CD incidence was observed amongst vaccinated patients. Lower rates of vaccination against hepatitis B and HPV observed in patients with CD compared to referents may be due to the reluctance of physicians to vaccinate patients considered at risk of CD.

Comprehensive analysis of patients with neuromyelitis optica spectrum disorder (NMOSD) combined with chronic hepatitis B (CHB) infection and seropositive for anti-aquaporin-4 antibody

Previous research indicated the association between hepatitis B virus (HBV) infection/vaccination and the onset of demyelinating diseases. However, most of these studies were single case reports, and comprehensive data are still scarce. Here we present a comprehensive analysis of 10 patients with neuromyelitis optica spectrum disorder (NMOSD) combined with chronic hepatitis B (CHB) infection and seropositive for anti-aquaporin-4 antibody (AQP4-Ab). Demographic, clinical, laboratory, neuroimaging, outcome, and follow-up data of the 10 patients were retrospectively analyzed. The median age at the onset of NMOSD was 35 years (range 25-43). Nine patients were female (90%). All patients were positive for HBsAg and had been diagnosed with CHB earlier than with NMOSD. One patient had an autoimmune disease. All patients had normal thyroid function. Paresthesia and visual impairment were the most common clinical symptoms. The cerebrospinal fluid (CSF) parameters (protein and glucose) were normal in 10 cases, whereas slightly higher CSF white blood cell count was detected in 3 patients. The brain and spinal cord magnetic resonance imaging findings were abnormal in 8 patients. All patients were treated with hormone and immunosuppressive therapy, and anti-HBV agents. Patients with detectable serum HBV DNA were more prone to liver damage after receiving high doses of corticosteroids. In 8 patients, the symptoms improved before they were discharged. Two patients with optic neuritis (ON) maintained the symptoms. A month later, 1/8 patient had recurrence of symptoms, and one ON patient progressed to NMO. Overall, the characteristics of NMOSD patients with CHB and seropositive for AQP4-Ab are usually nonspecific. Abnormal liver function test results in NMOSD patients should be a warning of possible CHB infection, and the treatment should be modified accordingly.

Vaccine-associated inflammatory diseases of the central nervous system: from signals to causation

PURPOSE OF REVIEW

As the most cost-effective intervention in preventive medicine and as a crucial element of any public health program, vaccination is used extensively with over 90% coverage in many countries. As approximately 5-8% of the population in developed countries suffer from an autoimmune disorder, people with an autoimmune disease are most likely to be exposed to some vaccines before or after the disease onset. In fact, a number of inflammatory disorders of the central nervous system have been associated with the administration of various vaccines. These adverse events, be they spurious associations or genuine reactions to the vaccine, may lead to difficulties in obtaining public trust in mass vaccination programs. There is, thus, an urgent need to understand whether vaccination triggers or enhances autoimmune responses.

RECENT FINDINGS

By reviewing vaccine-associated inflammatory diseases of the central nervous system, this study describes the current knowledge on whether the safety signal was coincidental, as in the case of multiple sclerosis with several vaccines, or truly reflected a causal link, as in narcolepsy with cataplexy following pandemic H1N1 influenza virus vaccination.

SUMMARY

The lessons learnt emphasize a central role of thorough, ideally prospective, epidemiological studies followed, if the signal is deemed plausible or real, by immunological investigations.

Central nervous system demyelinating diseases and recombinant hepatitis B vaccination: a critical systematic review of scientific production

The etiology of multiple sclerosis has not yet been fully described. A potential link between the recombinant hepatitis B vaccine and an increased risk of onset or exacerbation of multiple sclerosis emerged in the mid-1990s, leading to several spontaneous reports and studies investigating this association. We conducted a critical systematic review aimed at assessing whether hepatitis B vaccination increases the risk of onset or relapse of multiple sclerosis and other central nervous system demyelinating diseases. MEDLINE and EMBASE were used as data sources, and the search covered the period between 1981 and 2011. Twelve references met the inclusion criteria. No significant increased risk of onset or relapse of the diseases considered was associated with hepatitis B vaccination, except in one study. Most studies included in this review displayed methodological limitations and heterogeneity among them, which rendered it impossible to draw robust conclusions about the safety of hepatitis B vaccination in healthy subjects and patients with multiple sclerosis. Therefore, on the basis of current data there is no need to modify the vaccination recommendations; however, there is a need to improve the quality of observational studies with emphasis on certain considerations that are discussed in this review.

Autoimmunity following hepatitis B vaccine as part of the spectrum of 'Autoimmune (Auto-inflammatory) Syndrome induced by Adjuvants' (ASIA): analysis of 93 cases

OBJECTIVES

In this study we analyzed the clinical and demographic manifestations among patients diagnosed with immune/autoimmune-mediated diseases post-hepatitis B vaccination. We aimed to find common denominators for all patients, regardless of different diagnosed diseases, as well as the correlation to the criteria of Autoimmune (Auto-inflammatory) Syndrome induced by Adjuvants (ASIA).

PATIENTS AND METHODS

We have retrospectively analyzed the medical records of 114 patients, from different centers in the USA, diagnosed with immune-mediated diseases following immunization with hepatitis-B vaccine (HBVv). All patients in this cohort sought legal consultation. Of these, 93/114 patients diagnosed with disease before applying for legal consultation were included in the study. All medical records were evaluated for demographics, medical history, number of vaccine doses, peri-immunization adverse events and clinical manifestations of diseases. In addition, available blood tests, imaging results, treatments and outcomes were recorded. Signs and symptoms of the different immune-mediated diseases were grouped according to the organ or system involved. ASIA criteria were applied to all patients.

RESULTS

The mean age of 93 patients was 26.5 ± 15 years; 69.2% were female and 21% were considered autoimmune susceptible. The mean latency period from the last dose of HBVv and onset of symptoms was 43.2 days. Of note, 47% of patients continued with the immunization program despite experiencing adverse events. Manifestations that were commonly reported included neuro-psychiatric (70%), fatigue (42%) mucocutaneous (30%), musculoskeletal (59%) and gastrointestinal (50%) complaints. Elevated titers of autoantibodies were documented in 80% of sera tested. In this cohort 80/93 patients (86%), comprising 57/59 (96%) adults and 23/34 (68%) children, fulfilled the required criteria for ASIA.

CONCLUSIONS

Common clinical characteristics were observed among 93 patients diagnosed with immune-mediated conditions post-HBVv, suggesting a common denominator in these diseases. In addition, risk factors such as history of autoimmune diseases and the appearance of adverse event(s) during immunization may serve to predict the risk of post-immunization diseases. The ASIA criteria were found to be very useful among adults with post-vaccination events. The application of the ASIA criteria to pediatric populations requires further study.

Hepatitis B virus (HBV) and autoimmune disease

The etiology and pathogenesis of autoimmune diseases have long been an enigmatic subject that have involved genetic and environmental factors. Recent intriguing data has contributed to the mechanisms involved, including the relationship of infectious agents and loss of tolerance. This loss of tolerance is illustrated by the data on the immune response to Hepatitis B virus such as the molecular mimicry between HBV antigens and self proteins, the generation of immune complexes between HBV antigens and antibodies, and apoptosis/tissue damage resulting in the exposure of intracellular antigens to the immune system. In this paper, we review the current database related to HBV infection and a variety of autoimmune conditions, including autoimmune hepatitis, systemic lupus erythematosus, aplastic anemia, antiphospholipid syndrome, polyarteritis nodosa, rheumatoid arthritis, type 1 diabetes, multiple sclerosis, thyroid disease and uveitis.

Adverse events following immunization: perception and evidence

PURPOSE OF REVIEW

The aim of this article is to highlight the evidence on new and ongoing vaccine safety concerns in the light of several vaccines recently licensed and others made available and recommended more widely.

RECENT FINDINGS

There is increasingly convincing epidemiologic and laboratory evidence against a causal relation of several alleged adverse events following immunization. The scientific framework to detect and investigate adverse events following immunization is increasingly robust.

SUMMARY

Currently available vaccines are safe in immunocompetent individuals and there is no evidence to deviate from current immunization schedules.

Travel medicine interventions and neurological disease

As a consequence of increased mobility worldwide, persons with underlying medical conditions set out on a journey more often than in the past. Among pre-existing medical conditions, some neurological diseases, including multiple sclerosis and other demyelinating diseases, Guillain-Barré syndrome and myasthenia gravis often create management problems to travel medicine practitioners. There is some concern that these conditions could be worsened either by naturally acquired infections or by some travel medicine interventions. The aim of this review is to suggest a practical approach to each of these conditions and to examine the feasibility and the impact of travel medicine interventions on the underlying disease.