Encephalitis after hepatitis B vaccination: recurrent disseminated encephalitis or MS?

Vaccination frequency in people newly diagnosed with multiple sclerosis

BACKGROUND

Infections are discussed as risk factor for multiple sclerosis (MS) development and relapses. This may lead to decreased vaccination frequency in newly diagnosed patients.

OBJECTIVE

The aim of this study was to evaluate the relation of MS diagnosis to subsequent vaccination frequency.

METHODS

Based on German ambulatory claims data from 2005 to 2019, regression models were used to assess the relation of MS diagnosis (n = 12,270) to vaccination. A cohort of patients with MS was compared to control cohorts with Crohn's disease, psoriasis, and without these autoimmune diseases (total n = 198,126) in the 5 years after and before diagnosis.

RESULTS

Patients with MS were less likely to be vaccinated compared to persons without the autoimmune diseases 5 years after diagnosis (odds ratio = 0.91, p < 0.001). Exceptions were vaccinations against influenza (1.29, p < 0.001) and pneumococci (1.41, p < 0.001). Differences were strong but less pronounced after than before diagnosis (p < 0.001). The likelihood of vaccination was also lower compared to patients with Crohn's disease or psoriasis.

CONCLUSIONS

Patients with MS were not adequately vaccinated despite guideline recommendations. Increasing awareness about the importance of vaccination is warranted to reduce the risk of infection, in particular, in patients with MS receiving immunotherapies.

A review of the potential neurological adverse events of COVID-19 vaccines

Despite the advantages of getting access to the coronavirus disease 2019 (COVID-19) vaccines, their potential ability to induce severe adverse events (AEs) has been a significant concern. Neurological complications are significant among the various adverse events following immunization (AEFI) due to their likely durability and debilitating sequelae. Neurological AEs following COVID-19 vaccination can either exacerbate or induce new-onset neuro-immunologic diseases, such as myasthenia gravis (MG) and Guillain-Barre syndrome (GBS). The more severe spectrum of AEs post-COVID19 vaccines has included seizures, reactivation of the varicella-zoster virus, strokes, GBS, Bell's palsy, transverse myelitis (TM), and acute disseminated encephalomyelitis (ADEM). Here, we discuss each of these neurological adverse effects separately.

Vaccination of multiple sclerosis patients during the COVID-19 era: Novel insights into vaccine safety and immunogenicity

Multiple sclerosis (MS) is an incurable autoimmune disease known to cause widespread demyelinating lesions in the central nervous system (CNS) and a host of debilitating symptoms in patients. The development of MS is believed to be driven by the breakdown of the blood brain barrier, subsequent infiltration by CD4⁺ and CD8⁺ T cells, and widespread CNS inflammation and demyelination. Disease modifying therapies (DMTs) profoundly disrupt these processes and therefore compose an essential component of disease management. However, the effects of these therapeutic agents on vaccine safety and immunogenicity in individuals with MS are not yet fully understood. As such, the primary objective of this review article was to summarize the findings of recently conducted studies on vaccine safety and immunogenicity in MS patients treated with DMTs, particularly in the context of the ongoing coronavirus disease 2019 (COVID-19) pandemic. Discussed in this review are vaccinations against influenza, yellow fever, human papillomavirus, measles, mumps, rubella, Streptococcus pneumoniae, hepatitis B, and COVID-19. This article additionally reviews our current understanding of COVID-19 severity and incidence in this patient population, the risks and benefits of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and vaccination guidelines set forth by MS societies and organizations.

The effect of the BNT162b2 vaccine on antinuclear antibody and antiphospholipid antibody levels

The Food and Drug Administration (FDA) approved the first SARS-CoV-2 mRNA vaccine (Pfizer-BioNTech) in December 2020. New adverse events have emerged since these vaccines have reached market. Although no clear association between messenger ribonucleic acid (mRNA) vaccines and autoimmunity has emerged, the significance of such an association warrants further exploration. After obtaining consent, a standardized survey on baseline characteristics and other relevant variables was conducted on unvaccinated individuals who were scheduled for vaccination and had not previously contracted COVID-19. Blood samples were collected from participants prior to the first dose, prior to the second dose, and 1 month after the second dose. All collected samples were tested for antinuclear antibody (ANA) titers using indirect immunofluorescence microscopy kits, and antiphospholipid (APS) immunoglobulin M (IgM) and immunoglobulin G (IgG) levels using an enzyme-linked immunoassay (ELISA) technique. ANA titers were positive for 9 participants out of 101 (8.9%) in the first pre-vaccination draw. For the second draw, the number of participants testing positive for ANA decreased to 5 (5%). For the last draw, 6 (5.9%) participants tested positive for ANA titers. One participant tested positive for APS IgM at the first pre-vaccination draw, 2 tested positive at the second draw, and 2 at the third draw. As for APS IgG titers, all participants tested negative in the three draws. McNemar's test for two dependent categorical outcomes was conducted on all variables and did not show a statistical significance. The McNemar test of these two composite variables (i.e., ANA/APS, first draw vs. ANA/APS, second and third draws) did not show statistical significance. The 2-sided exact significance of the McNemar test was 1.0. The Friedman test also showed no significance (p = 0.459). No association was found between BNT162b2 vaccine administration and changes in APS and ANA titers. The benefits of the BNT162b2 vaccine significantly outweigh any possible risk of autoimmune dysregulation considering the current evidence.

Safety of Multiple Vaccinations and Durability of Vaccine-Induced Antibodies in an Italian Military Cohort 5 Years after Immunization

We previously examined the safety and immunogenicity of multiple vaccines administered to a military cohort, divided into two groups, the first composed of students at military schools, thus operating inside the national borders for at least 3 years, and the other formed of soldiers periodically engaged in a 9-month-long mission abroad (Lebanon). In the current study, we analyzed 112 individuals of this cohort, 50 pertaining to the first group and 62 to the second group, in order to examine the possible late appearance of side effects and to calculate the half-life of the induced antibodies. Moreover, the possible involvement of B-cell polyclonal activation as a pathogenetic mechanism for long term antibody persistence has even been explored. No late side effects, as far as autoimmunity and/or lymphoproliferation appearance, have been noticed. The long duration of the vaccine induced anti-HAV antibodies has been confirmed, whereas the antibodies induced by tetravalent meningococcal polysaccharide vaccine have been found to persist above the threshold for putative protection for a longer time, and anti-tetanus, diphtheria, and polio 1 and 3 for a shorter time than previously estimated. No signs of polyclonal B-cell activation have been found, as a possible mechanism to understand the long antibody persistence.

Vaccinations and Autoimmune Diseases

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

HBV vaccine and risk of developing multiple sclerosis: a systematic review and meta-analysis

Hepatitis B virus (HBV) infection is one the most common in the world. Aim of this study is to perform a systematic review on the relationship between HBV vaccination and multiple sclerosis. Research was conducted on Pubmed, ISI Web of Science, and Scopus. Terms "hepatitis b vaccination" and "multiple sclerosis" were used. Meta-analysis and metaregression were performed. 414 papers were found. Seven articles were selected. For the reported crude risk estimates for MS no statistically significant association was observed with pooled OR 1,19 (95%CI: 0,96-1,49). For the adjusted ORs, the pooled odds ratio (OR) was 0, 965 (95%CI: 0,886- 1,051). Meta regression show that year of publication is negatively (β: -0,019; P < 0.001) and NOS score and publishing in Europe are positively associated with O.R. value. Funnel plot showed the presence of publication bias. Results showed that Hepatitis B vaccination is not associated with an increased risk of developing MS.

Causality assessment of adverse events following immunization: the problem of multifactorial pathology

The analysis of Adverse Events Following Immunization (AEFI) is important in a balanced epidemiological evaluation of vaccines and in the issues related to national vaccine injury compensation programs. If manufacturing defects or vaccine storage and delivering errors are excluded, the majority of adverse reactions to vaccines occur as excessive or biased inflammatory and immune responses. These unwanted phenomena, occasionally severe, are associated with many different endogenous and exogenous factors, which often interact in complex ways. The confirmation or denial of the causal link between an AEFI and vaccination is determined pursuant to WHO guidelines, which propose a four-step analysis and algorithmic diagramming. The evaluation process from the onset considers all possible "other causes" that can explain the AEFI and thus exclude the role of the vaccine. Subsequently, even if there was biological plausibility and temporal compatibility for a causal association between the vaccine and the AEFI, the guidelines ask to look for any possible evidence that the vaccine could not have caused that event. Such an algorithmic method presents some concerns that are discussed here, in the light of the multifactorial nature of the inflammatory and immune pathologies induced by vaccines, including emerging knowledge of genetic susceptibility to adverse effects. It is proposed that the causality assessment could exclude a consistent association of the adverse event with the vaccine only when the presumed "other cause" is independent of an interaction with the vaccine. Furthermore, the scientific literature should be viewed not as an exclusion criterion but as a comprehensive analysis of all the evidence for or against the role of the vaccine in causing an adverse reaction. These issues are discussed in relation to the laws that, in some countries, regulate the mandatory vaccinations and the compensation for those who have suffered serious adverse effects.

Causality assessment of adverse events following immunization: the problem of multifactorial pathology

The analysis of Adverse Events Following Immunization (AEFI) is important in a balanced epidemiological evaluation of vaccines and in the issues related to vaccine injury compensation programs. The majority of adverse reactions to vaccines occur as excessive or biased inflammatory and immune responses. These unwanted phenomena, occasionally severe, are associated with many different endogenous and exogenous factors, which often interact in complex ways. The confirmation or denial of the causal link between an AEFI and vaccination is determined pursuant to WHO guidelines, which propose a four-step analysis and algorithmic diagramming. The evaluation process from the onset considers all possible "other causes" that might explain the AEFI and thus exclude the role of the vaccine. Subsequently, even if there was biological plausibility and temporal compatibility for a causal association between the vaccine and the AEFI, the guidelines ask to look for any possible evidence that the vaccine could not have caused that event. Such an algorithmic method presents several concerns that are discussed here, in the light of the multifactorial nature of the inflammatory and immune pathologies induced by vaccines, including emerging knowledge of genetic susceptibility to adverse effects. It is proposed that the causality assessment could exclude a consistent association of the adverse event with the vaccine only when the presumed "other cause" is independent of an interaction with the vaccine. Furthermore, the scientific literature should be viewed not as an exclusion criterion but as a comprehensive analysis of all the evidence for or against the role of the vaccine in causing an adverse reaction. Given these inadequacies in the evaluation of multifactorial diseases, the WHO guidelines need to be reevaluated and revised. These issues are discussed in relation to the laws that, in some countries, regulate the mandatory vaccinations and the compensation for those who have suffered serious adverse effects.

Vaccination in Multiple Sclerosis: Friend or Foe?

Multiple sclerosis (MS) is a debilitating disease of the central nervous systems (CNS). Disease-modifying treatments (including immunosuppressive treatments) have shown positive effects on the disease course, but are associated with systemic consequences on the immune system and may increase the risk of infections and alter vaccine efficiency. Therefore, vaccination of MS patients is of major interest. Over the last years, vaccine hesitancy has steadily grown especially in Western countries, partly due to fear of sequelae arising from vaccination, especially neurological disorders. The interaction of vaccination and MS has been discussed for decades. In this review, we highlight the immunology of vaccination, provide a review of literature and discuss the clinical consideration of MS, vaccination and immunosuppression. In conclusion, there is consensus that MS cannot be caused by vaccines, neither by inactivated nor by live vaccines. However, particular attention should be paid to two aspects: First, in immunocompromised patients, live vaccines may lead to a stronger immune reaction with signs of the disease against which the patients have been vaccinated, albeit in weakened form. Second, protection provided by vaccination should be controlled in patients who have been vaccinated while receiving immunomodulatory or immunosuppressive treatment. In conclusion, there is evidence that systemic infections can worsen MS, thus vaccination will lower the risk of relapses by reducing the risk of infections. Therefore, vaccination should be in general recommended to MS patients.

Central Demyelinating Diseases after Vaccination Against Hepatitis B Virus: A Disproportionality Analysis within the VAERS Database

INTRODUCTION

Hepatitis B (HB) vaccination programs were set up worldwide in the early 1990s. Despite their major focus on reducing the burden of HB infection, they have seldom achieved the targeted population coverage in most countries, including the USA, with around 24.5% of adults being vaccinated against HB. Among proposed reasons for this is the persisting doubt about a possible link between HB vaccination and the occurrence of cases of multiple sclerosis (MS).

OBJECTIVE

Our objective was to evaluate a potential safety signal between MS and HB vaccination. We conducted a disproportionality analysis (DPA) using the cases reported to the Vaccine Adverse Event Reporting System (VAERS).

METHODS

We calculated the proportional reporting rate (PRR) and reporting odds ratio (ROR) of MS having occurred within the 120 days following HB immunization in adults aged 19-49 years when compared with other vaccines using the reports recorded in the VAERS database. Both ratios were estimated globally and then according to the origin of reports (USA vs. non-USA). We then performed a sensitivity analysis using a broader category of demyelinating events.

FINDINGS

MS cases following HB vaccination were more likely to originate from outside the USA and to be reported before 2000 than those associated with other immunizations. All computed ratios were found to be statistically significant, with PRRs ranging from 3.48 to 5.56 and RORs ranging from 3.48 to 5.62. When considering the geographical origin, similar RORs were obtained for both US and non-US cases.

CONCLUSION

In VAERS, MS cases were up to five times more likely to be reported after an HB vaccination than after any other vaccination. Since DPA is mainly suited for hypothesis generation, further studies evaluating the nature of the link between MS and HB vaccination would be of considerable importance.

Vaccines and the risk of acute disseminated encephalomyelitis

BACKGROUND

It is important to examine the risk of Acute disseminated encephalomyelitis (ADEM) after vaccination.

METHODS

We conducted a nested case-control study between January 2011 and December 2015. Four controls per case were matched for age, gender, address. An independent expert committee validated the diagnoses of cases and controls. Data on vaccinations were obtained from computerized vaccination records. The analyses were conducted with the use of conditional logistic regression.

RESULTS

The analyses include 272 cases of ADEM and 1096 controls. No increase in the risk of ADEM was observed for vaccination against hepatitis B, influenza, polio(live), diphtheria, pertuss(acellular), tetanusis, measles, mumps, rubella, Japanese Encephalitis, meningitis, hepatitis A, varicella and rabies vaccines. Vaccine was associated with a statistically significant increase in risk in the 31-60-day exposure interval (OR, 4.04 [95% CI, 1.07-12.69]), but not the 0-30 and 61-180-day interval. There was no association between vaccine received and the recurrence of ADEM.

CONCLUSIONS

Findings from the present study do not demonstrate an association of vaccines with an increased risk of ADEM and its recurrence among either paediatric (≤18 years) or adult (>18 years) individuals within the 180 days after vaccinations. The finding in children in the 31-60 day risk interval is likely coincidental and was not confirmed in separate self-control analyses.

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.

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.

Hepatitis B vaccination and associated oral manifestations: a non-systematic review of literature and case reports

Hepatitis B vaccine has been administered in children and adults routinely to reduce the incidence of the disease. Even though, hepatitis B vaccine is considered as highly safe, some adverse reactions have been reported. A literature search was carried out in PubMed, accessed via the National Library of Medicine PubMed interface, searching used the following keywords: Hepatitis B vaccine and complications from 1980 to 2014. A total of 1147 articles were obtained out of which articles, which discuss the complications occurring orally or occurring elsewhere in the body, which have the potential to manifest orally after hepatitis B vaccination were selected. A total of 82 articles were identified which included 58 case series or case reports, 15 review articles, 4 cross sectional studies, 3 prospective cohort studies, one retrospective cohort study and a case control study. After reviewing the literature, we observed that complications seen after Hepatitis B vaccination are sudden infant death syndrome, multiple sclerosis, chronic fatigue syndrome, idiopathic thrombocytopenic purpura, vasculititis optic neuritis, anaphylaxis, systemic lupus erytymatosus, lichen planus and neuro-muscular disorder. Of these complications, some are manifested orally or have the potential to manifest orally. Although, most of the complications are self-limiting, some are very serious conditions, which require hospitalization with immediate medical attention.

Safety of hepatitis B vaccines

Although concerns about vaccine safety have increased, true adverse reactions associated with hepatitis B vaccines are few, apart from minor symptoms at the site of injection and occasionally systemic reactions. There is no evidence of an association with hepatitis B vaccination and Sudden Infant Death Syndrome, Multiple Sclerosis and the Chronic Fatigue Syndrome. Hepatitis B vaccines are safe and essential for the prevention of this important and common infection.

Human papillomavirus vaccine safety in Australia: experience to date and issues for surveillance

Australia was one of the first countries to licence a quadrivalent human papillomavirus (HPV) vaccine, rapidly followed by a federally funded program of universal vaccination of a broad age group of females through schools (12 to 18 years) and primary care (19 to 26 years). As of August 2009, more than 5.8 million doses of Gardasil((R)) (quadrivalent; Merck, New Jersey, USA) have been distributed in Australia and a total of 1394 suspected adverse events following immunisation (AEFI) have been reported to the passive surveillance system. Most reports are of common and expected reactions. Case series of more uncommon and serious AEFI, both known to be potentially vaccine related (anaphylaxis, conversion disorders and lipoatrophy) and otherwise (multiple sclerosis and pancreatitis) have been published.

Disseminated encephalomyelitis in children

The advent of MRI has contributed to increase the interest and awareness in childhood white matter disorders. A major priority is to distinguish transient and self-limited demyelinating syndromes like disseminated encephalomyelitis (DEM), from life-long diseases like multiple sclerosis (MS). However, the term DEM has been inconsistently applied across studies due to the lack of clear clinical and neuroimaging diagnostic criteria. The present review summarizes the available literature on DEM in children, outlines the main clinical and neuroimaging features at presentation, pathogenesis and outcome, and its differentiation from other conditions with acute impact in the CNS. The recently proposed clinical definitions for monophasic disseminated encephalomyelitis and its relapsing variants are discussed, and controversies surrounding the diagnosis of MS in children are addressed.

Post-vaccination encephalomyelitis: literature review and illustrative case

Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease of the central nervous system that is usually considered a monophasic disease. ADEM forms one of several categories of primary inflammatory demyelinating disorders of the central nervous system including multiple sclerosis, optic neuropathy, acute transverse myelitis, and neuromyelitis optica (Devic's disease). Post-infectious and post-immunisation encephalomyelitis make up about three-quarters of cases, where the timing of a febrile event is associated with the onset of neurological disease. Post-vaccination ADEM has been associated with several vaccines such as rabies, diphtheria-tetanus-polio, smallpox, measles, mumps, rubella, Japanese B encephalitis, pertussis, influenza, hepatitis B, and the Hog vaccine. We review ADEM with particular emphasis on vaccination as the precipitating factor. We performed a literature search using Medline (1976-2007) with search terms including "ADEM", "acute disseminated encephalomyelitis", "encephalomyelitis", "vaccination", and "immunisation". A patient presenting with bilateral optic neuropathies within 3 weeks of "inactivated" influenza vaccination followed by delayed onset of ADEM 3 months post-vaccination is described.

Acute disseminated encephalomyelitis: clinical and pathogenesis features

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated disorder of the central nervous system (CNS). Disease typically starts with an abrupt onset of neurologic symptoms and signs within days to weeks after a viral infection or immunization. Neuropathological examination of the CNS in ADEM reveals involvement of white matter, with infiltration of monocytoid cells and perivenous demyelination.

Improvement of advanced postvaccinal demyelinating encephalitis due to plasmapheresis

We report a case of acute demyelinating encephalitis that occurred after viral vaccination against hepatitis A-, hepatitis B-, and poliovirus and vaccination against bacterial toxins of diphtheria and tetanus. After different diagnosis had been excluded, we diagnosed postvaccinal demyelinating encephalitis and started treatment with high dose intravenous methylprednisolone, followed by peroral application in decreasing dosages for three weeks. A few days after the treatment with methylprednisolone had been finished, the patient's medical condition deteriorated again. Thus, we initiated plasma exchange at an advanced state of illness, which led to significant continuous improvement. The role of plasma exchange is discussed controversially, in particular the issue of timing. We report a case that shows improvement due to plasmapheresis several weeks after symptom onset.

Disseminated encephalomyelitis and multiple sclerosis: two different diseases - a critical review

The practice of initiating immunomodulatory treatment immediately after a clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS) emphasizes the need to distinguish between disseminated encephalomyelitis (DEM) and MS. Their clinical, genetic, imaging, and histopathological characteristics establish that they are distinct disease entities. Acute and recurrent DEM are more common in children, but also occur in adults. DEM is polysymptomatic and includes signs and symptoms rarely encountered in MS, such as fever, alterations of the state of consciousness, cognitive and aphasic symptoms, and meningism. Cerebrospinal oligoclonal bands are rare. Magnetic resonance imaging (MRI) is the best means of distinguishing between DEM and MS. In the former, the lesion load is heavy, thalamus or basal ganglia are often affected, and early in the disease most of the lesions are usually larger than those of MS and enhance with gadolinium. The MRI spinal cord lesions are longer than three vertebral segments, and define neuromyelitis optica (NMO). Antibodies against aquaporin-4 are present in some NMO, but are also found in cases of MS and DEM. Most NMO are forms of DEM, not MS, and are identical with the 'Oriental' or 'optico-spinal' form of MS.

Development of multiple sclerosis after vaccination against hepatitis B: a study based on human leucocyte antigen haplotypes

The aetiology of multiple sclerosis (MS) is still not fully understood. Infectious agents are believed to play a role in the development of this multifactorial disease. Cases in which this disease occurs after administration of both plasma-derived and recombinant hepatitis B vaccines have been reported. In this study, we compared a group of 11 MS patients who developed first clinical symptoms after hepatitis B vaccination (group I) with 71 MS patients who were never vaccinated against hepatitis B and were negative for hepatitis B serology (group II), and 20 healthy controls (group III). Mean age was 27.75 years (19-39) in group I, 30.16 years (18-50) in group II, and 34.4 years (18-50) in group III. Mean attack rate after 2 years was 1.5 in group I and 1.63 in group II. Mean Expanded Disability Status Scale score after 2 years was 1.31 in group I and 1.89 in group II. Human leucocyte antigen (HLA) typing and serology for hepatitis B surface antigen were performed in all groups. In groups I and II, HLA-DR2 was more frequent than in normal healthy subjects. This reflects the general role of HLA in the pathogenesis of MS but suggests that antigen presentation by different HLA is not involved in the development of MS after hepatitis B vaccination. Since there was no difference in the clinical features between vaccinated and nonvaccinated MS patients, this study supports recent reports that hepatitis B vaccination is safe in MS patients and that hepatitis B vaccination is not involved in the development of MS.

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.

Protective efficacy, immunotherapeutic potential, and safety of hepatitis B vaccines

Hepatitis B vaccines are highly effective and safe and have been incorporated into national immunization programs in over 150 countries. The major humoral immune response is to the common a determinant of the surface antigen protein of the virus. Approximately 5-10% of healthy immunocompetent subjects do not mount an antibody response (anti-HBs). Non-response is associated with different HLA-DR alleles and impaired Th cell response, among other factors such as route of injection, age, gender, body mass, and other factors. Important hepatitis B surface antigen variants have also been identified, which may have a potential impact on immunization and routine screening of blood, blood products and tissues, and organs for transplantation. Strategies for hepatitis B immunization are reviewed. Over 1,000 million doses of hepatitis B vaccine have been used with an outstanding record of safety. There is no evidence of an association between hepatitis B vaccines and the sudden infant death syndrome, chronic fatigue syndrome, and multiple sclerosis (MS). Several studies are in progress on treatment of chronic hepatitis B infection by immunization with multiple antigenic components, combination of vaccine with antiviral drugs and cytokines, T cell vaccines, DNA vaccines alone or with DNA encoded immunomodulatory cytokines, and direct genetic manipulation of antigen presenting cells.

[Acute disseminated encephalomyelitis. Pathogenesis, diagnosis, treatment, and prognosis]

Acute disseminated encephalomyelitis (ADEM) is typically a monophasic, demyelinating disease of the CNS that predominantly affects children. Typically, its clinical symptoms follow an infection or vaccination. In this regard, numerous viral and bacterial pathogens as well as several vaccinations have been associated with ADEM. Studies from animal models suggest that primary and secondary autoimmune responses may contribute to CNS inflammation and demyelination in ADEM. The diagnosis of ADEM is strongly suggested by a close temporal relationship between a viral infection or immunization and the onset of neurologic symptoms, and it is supported by extensive, multifocal, subcortical white-matter disease on brain magnetic resonance imaging. While mild lymphocytic pleocytosis and elevated proteins are detectable in the CSF in ADEM, oligoclonal bands are not always present. Treatment of this disorder consists of anti-inflammatory and immunosuppressive therapies, and the prognosis is generally considered favorable.

Consequence or coincidence? The occurrence, pathogenesis and significance of autoimmune manifestations after viral vaccines

BACKGROUND

Viruses and virus-induced lymphokines may have an important role in the pathogenesis of autoimmunity (Schattner A. Clin Immunol Immunopathol; 1994). The occurrence and significance of autoimmune manifestations after the administration of viral vaccines remain controversial.

METHODS

Medline search of all relevant publications from 1966 through June 2004 with special emphasis on search of each individual autoimmune manifestation and vaccination, as well as specifically searching each viral vaccine for all potential autoimmune syndromes reported. All relevant publications were retrieved and critically analyzed.

RESULTS

The most frequently reported autoimmune manifestations for the various vaccinations, were: hepatitis A virus (HAV)--none; hepatitis B virus (HBV)--rheumatoid arthritis, reactive arthritis, vasculitis, encephalitis, neuropathy, thrombocytopenia; measles, mumps and rubella vaccine (MMR)--acute arthritis or arthralgia, chronic arthritis, thrombocytopenia; influenza--Guillain-Barre syndrome (GBS), vasculitis; polio--GBS; varicella--mainly neurological syndromes. Even these 'frequent' associations relate to a relatively small number of patients. Whenever controlled studies of autoimmunity following viral vaccines were undertaken, no evidence of an association was found.

CONCLUSIONS

Very few patients may develop some autoimmune diseases following viral vaccination (in particular - arthropathy, vasculitis, neurological dysfunction and thrombocytopenia). For the overwhelming majority of people, vaccines are safe and no evidence linking viral vaccines with type 1 diabetes, multiple sclerosis (MS) or inflammatory bowel disease can be found.

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

Demyelination events or multiple sclerosis following hepatitis B virus (HBV) vaccination have been reported. We therefore compared the T-cell response to HBsAg in patients with CNS demyelination following HBV vaccination and in HBV-vaccinated healthy individuals. Our data showed no differences in terms of T-cell proliferation or cytokine production between these groups and may help to allay concerns that HBV vaccination might trigger a deleterious immune response.

Multiple sclerosis and hepatitis B vaccination: Could minute contamination of the vaccine by partial Hepatitis B virus polymerase play a role through molecular mimicry?

Reports of multiple sclerosis developing after hepatitis B vaccination have led to the concern that this vaccine might be a cause of multiple sclerosis in previously healthy subjects. Some articles evidenced that minor Hepatitis B virus (HBV) polymerase proteins could be produced by alternative transcriptional or translational strategies. Their detection is very difficult because they are in minute concentration and probably enzymatically inactive, however, it was shown that they could be exposed on the outside of the virus particles and also be immunogenic. In addition, HBV polymerase shares significant amino acid similarities with the human myelin basic protein. We hypothesise that some of the apparent adverse reactions to the vaccine could be due to a process called of molecular mimicry, the HBV polymerase, which could be a contaminant in the recombinant or plasma-derived vaccines, could act as autoantigens and induce autoimmune demyelinating diseases such as multiple sclerosis.

Childhood Infections as Risk Factors for Multiple Sclerosis: Belgrade Case-Control Study

The aim of this case-control study was to analyze the role of childhood infections and vaccinations in patients with MS in the Belgrade population. The study group comprised 110 cases with definite MS according to Poser's criteria, in whom onset symptoms occurred up to 2 years prior to the interview. An equal number of controls, individually matched by sex, age and area of residence, was recruited from patients with various nonautoimmune neurological disorders. Measles (OR = 2.6, 95%CI 1.4-5.0), chickenpox (OR = 3.0, 95%CI 1.5-6.0), rubella (OR = 2.4, 95%CI 1.2-4.7), whooping cough (OR = 1.9, 95%CI 0.8-4.4), and mumps (OR = 1.8, 95%CI 0.8-4.5), at age < or = 7 years, were more frequently reported by MS cases. The total number of childhood viral infections (including measles, rubella, chickenpox, and mumps) at age < or = 7 years was significantly higher in MS cases than in controls (OR = 1.8, 95%CI 1.4-2.5). Concerning vaccinations, no statistically significant differences were found between groups. According to multivariate analysis, rubella (OR = 2.5, 95%CI 1.4-4.4, p = 0.001) and measles (OR = 2.4, 95%CI 1.3-4.3, p = 0.003) at age < or = 7 years were significantly related to MS.

Non-MS recurrent demyelinating diseases

The introduction of MRI has shown that the acute, recurrent (R), and multiphasic (M) forms of disseminated encephalomyelitis (DEM) are more common than suspected in adults, and that their MR images are sufficiently characteristic in most instances to make differentiation from multiple sclerosis (MS) possible. In addition, a number of clinical features of DEM are rarely seen in MS: fever, malaise, nausea, vomiting, positional vertigo, convulsions, aphasia, meningism, bilateral optic neuritis, and CSF leukocytosis and elevated protein. CSF oligoclonal bands are usually absent. It is remarkable that confusion between R- and MDEM and MS persists despite the numerous published reports on recurrent DEM dating back 70 years, many illustrating the characteristic MRIs. There are many case reports of DEM erroneously diagnosed as MS, Schilder's, Marburg's, Devic's, and Baló's disease, and, in particular brain tumors. It is probable that acute DEM is occasionally mistaken for a clinically isolated symptom of MS. Possible mechanisms for recurrence include localization at the site of a previous injury to the nervous system, or by the phenomenon of molecular mimicry. The importance of differentiating R- and MDEM from MS is greater today due to the recommendation that immunodulatory treatment be initiated in patients with a clinically isolated syndrome, or when the occurrence of a second clinical episode establishes the diagnosis of MS.

Acute disseminated encephalomyelitis in childhood: epidemiologic, clinical and laboratory features

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is a central nervous system demyelinating disease that usually follows an apparently benign infection in otherwise healthy young persons. The epidemiology, infectious antecedents and pathogenesis of ADEM are poorly characterized, and some ADEM patients are subsequently diagnosed with multiple sclerosis (MS).

METHODS

We retrospectively (1991-1998) and prospectively (1998-2000) studied all persons aged < 20 years diagnosed with ADEM from the 3 principal pediatric hospitals in San Diego County, CA, during 1991-2000. Acute neurologic abnormalities and imaging evidence of demyelination were required for study inclusion. Epidemiologic variables, risk factors, clinical course, laboratory and radiographic findings, neuropathology and treatment data were analyzed. Interleukin (IL)-12, interferon-gamma (IFN-gamma) and IL-10 were assayed in blinded manner on cerebrospinal fluid (CSF) obtained prospectively from a subset of ADEM cases and compared with CSF from patients with enteroviral (EV) meningoencephalitis confirmed by polymerase chain reaction (PCR) and controls without pleocytosis.

RESULTS

Data were analyzed on 42 children and adolescents diagnosed with ADEM during 1991-2000, and CSF IL-12, IFN-gamma and IL-10 levels were compared among ADEM (n = 14), EV meningoencephalitis (n = 14) and controls without pleocytosis (n = 28). Overall incidence of ADEM was 0.4/100,000/year; incidence quadrupled during 1998-2000 compared with earlier years. No gender, age stratum, ethnic group or geographic area was disproportionately affected. A total of 4 (9.5%) patients initially diagnosed with ADEM were subsequently diagnosed with MS after multiple episodes of demyelination. Although most children eventually recovered, 2 died, including 1 of the 3 ultimately diagnosed with MS. Magnetic resonance imaging was required for diagnosis among 74% of patients; computerized tomography findings were usually normal. Patients with EV had significantly higher mean CSF IFN-gamma (P = 0.005) and IL-10 (P = 0.05) than patients with ADEM and controls without CSF pleocytosis. CSF from ADEM patients had CSF cytokine values statistically similar to those of 3 patients subsequently diagnosed with MS.

CONCLUSIONS

ADEM is a potentially severe demyelinating disorder likely to be increasingly diagnosed as more magnetic resonance imaging studies are performed on patients with acute encephalopathy. Further characterization of the central nervous system inflammatory response will be needed to understand ADEM pathogenesis, to improve diagnostic and treatment strategies and to distinguish ADEM from MS.

Neurologic complications of immunization

In the United States and many other developed countries, active immunization of children has virtually eliminated poliomyelitis, measles, rubella, tetanus, and other diseases, such as disease due to Haemophilus influenzae type b. Individual vaccines can produce systemic or neurologic reactions ranging from minor events, such as pain and erythema at the injection site, to major complications, such as seizures, shock, encephalopathy, or death. Immunization programs have also generated considerable controversy, as witnessed by recent concerns regarding the relationship between vaccines or their constituents and autism or multiple sclerosis. This review summarizes current information regarding vaccines, the diseases that they prevent, and the potential relationships between vaccines and neurologic disease.

Aluminum inclusion macrophagic myofasciitis: a recently identified condition

The authors conclude that the persistence of aluminum hydroxide at the site of intramuscular injection is a novel finding which has an exact significance that remains to be established fully. It seems mandatory to evaluate possible long-term adverse effects induced by this compound, because this issue has not been addressed (in the past, aluminum hydroxide was believed to be cleared quickly from the body). If safety concerns about the long-term effects of aluminum hydroxide are confirmed, novel and alternative vaccine adjuvants to rescue vaccine-based strategies should be proposed to ensure the enormous benefit for public health that these vaccines provide worldwide.

Vaccination and autoimmune disease: what is the evidence?

As many as one in 20 people in Europe and North America have some form of autoimmune disease. These diseases arise in genetically predisposed individuals but require an environmental trigger. Of the many potential environmental factors, infections are the most likely cause. Microbial antigens can induce cross-reactive immune responses against self-antigens, whereas infections can non-specifically enhance their presentation to the immune system. The immune system uses fail-safe mechanisms to suppress infection-associated tissue damage and thus limits autoimmune responses. The association between infection and autoimmune disease has, however, stimulated a debate as to whether such diseases might also be triggered by vaccines. Indeed there are numerous claims and counter claims relating to such a risk. Here we review the mechanisms involved in the induction of autoimmunity and assess the implications for vaccination in human beings.

Parental perceptions surrounding risks and benefits of immunization

In recent years, parental concerns about vaccine safety have increased as the threat of disease has decreased. A national survey showed that, in general, parents agree that vaccines benefit their children and that their children may be at risk for contracting a disease if unvaccinated. When asked about understanding the benefits and risks of vaccines, most parents (57%) found numbers and statistics most helpful. A substantial minority (17%) of parents were somewhat or not confident in vaccine safety. Parents less confident in vaccine safety agreed less with the statement that they usually followed the advice of their child's doctor. Incomes and education levels affected responses. This positive relationship between confidence in vaccine safety and reliance on doctors for advice may indicate the need for healthcare providers to identify opportunities to (1) solicit questions about vaccine safety, (2) address vaccine safety-related questions in a way meaningful to parents, and (3) strengthen doctor-patient relationships. A parent communication tool is proposed.

Early-onset acute transverse myelitis following hepatitis B vaccination and respiratory infection: case report

Acute transverse myelitis is an acute inflammatory process of the spinal cord and it is a rare clinical syndrome in childhood. In this paper, we report a case of 3 years-old boy who developed acute onset tetraparesia following a viral respiratory infecction and hepatitis B vaccination. Magnetic resonance imaging of the spinal cord disclosed signal-intensity abnormalities from C4 to C3. A diagnosis of acute transverse myelitis was made and the patient was treated with IV methylprednisolone and IV immunoglobulin. The child had a fair outcome despite of the very acute course of the disease and the presence of a cervical sensory level which usually harbor a poor prognosis.