Epidemiology of autoimmune reactions induced by vaccination

Human prophylactic vaccine adjuvants and their determinant role in new vaccine formulations

Adjuvants have been considered for a long time to be an accessory and empirical component of vaccine formulations. However, accumulating evidence of their crucial role in initiating and directing the immune response has increased our awareness of the importance of adjuvant research in the past decade. Nevertheless, the importance of adjuvants still is not fully realized by many researchers working in the vaccine field, who are involved mostly in the search for better target antigens. The choice of a proper adjuvant can be determinant for obtaining the best results for a given vaccine candidate, but it is restricted due to intellectual property and know-how issues. Consequently, in most cases the selected adjuvant continues to be the aluminum salt, which has a record of safety, but predominantly constitutes a delivery system (DS). Ideally, new strategies should combine immune potentiators (IP) and DS by mixing both compounds or by obtaining structures that contain both IP and DS. In addition, the term immune polarizer has been introduced as an essential concept in the vaccine design strategies. Here, we review the theme, with emphasis on the discussion of the few licensed new adjuvants, the need for safe mucosal adjuvants and the adjuvant/immunopotentiating activity of conjugation. A summary of toxicology and regulatory issues will also be discussed, and the Finlay Adjuvant Platform is briefly summarized.

Assessing the safety of adjuvanted vaccines

Despite the very low risk-to-benefit ratio of vaccines, fear of negative side effects has discouraged many people from getting vaccinated, resulting in reemergence of previously controlled diseases such as measles, pertussis, and diphtheria. Part of this fear stems from the lack of public awareness of the many preclinical and clinical safety evaluations that vaccines must undergo before they are available to the general public, as well as from misperceptions of what adjuvants are or why they are used in vaccines. The resultant "black box" leads to a preoccupation with rare side effects (such as autoimmune diseases) that are speculated, but not proven, to be linked to some vaccinations. The focus of this review article is to open this black box and provide a conceptual framework for how vaccine safety is traditionally assessed. We discuss the strengths and shortcomings of tools that can be and are used preclinically (in animal studies), translationally (in biomarker studies with human sera or cells), statistically (for disease epidemiology), and clinically (in the design of human trials) to help ascertain the risk of the infrequent and delayed adverse events that arise in relation to adjuvanted vaccine administration.

Surveillance of autoimmune conditions following routine use of quadrivalent human papillomavirus vaccine

OBJECTIVE

An observational safety study of the quadrivalent human papillomavirus vaccine (HPV4) in women was conducted. This report presents findings from autoimmune surveillance. Design.  Subjects were followed for 180days after each HPV4 dose for new diagnoses of 16 prespecified autoimmune conditions.

SETTING

Two managed care organizations in California. Subjects.  Number of 189,629 women who received ≥1 dose of HPV4 between 08/2006 and 03/2008.

OUTCOME

Potential new-onset autoimmune condition cases amongst HPV4 recipients were identified by electronic medical records. Medical records of those with ≥12-month health plan membership prior to vaccination were reviewed by clinicians to confirm the diagnosis and determine the date of disease onset. The incidence of each autoimmune condition was estimated for unvaccinated women at one study site using multiple imputations and compared with that observed in vaccinated women. Incidence rate ratios (IRR) were calculated. Findings were reviewed by an independent Safety Review Committee (SRC).

RESULTS

Overall, 1014 potential new-onset cases were electronically identified; 719 were eligible for case review; 31-40% were confirmed as new onset. Of these, no cluster of disease onset in relation to vaccination timing, dose sequence or age was found for any autoimmune condition. None of the estimated IRR was significantly elevated except Hashimoto's disease [IRR=1.29, 95% confidence interval: 1.08-1.56]. Further investigation of temporal relationship and biological plausibility revealed no consistent evidence for a safety signal for autoimmune thyroid conditions. The SRC and the investigators identified no autoimmune safety concerns in this study.

CONCLUSIONS

No autoimmune safety signal was found in women vaccinated with HPV4.

Vaccination and risk of type 1 diabetes mellitus in active component U.S. Military, 2002-2008

AIMS/HYPOTHESIS

To evaluate whether vaccination increases the risk of type 1 diabetes mellitus in active component U.S. military personnel.

METHODS

We conducted a retrospective cohort study among active component U.S. military personnel age 17-35 years. Individuals with first time diagnoses of type 1 diabetes between January 1, 2002 and December 31, 2008 were identified using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. We used Poisson regression to estimate risk ratios between individual vaccine exposures and type 1 diabetes. Secondary analyses were performed controlling for receipt of multiple vaccines and available demographic variables.

RESULTS

Our study population consisted of 2,385,102 individuals followed for approximately 7,644,098 person-years of service. This included 1074 incident type 1 diabetes cases. We observed no significant increased risk of type 1 diabetes after vaccination with anthrax vaccine adsorbed (AVA) [RR=1.00; 95% CI (0.85, 1.17)], smallpox vaccine [RR=0.84; 95% (CI 0.70, 1.01)], typhoid vaccine [RR=1.03; 95% CI (0.87, 1.22)], hepatitis B vaccine [RR=0.83; 95% CI (0.72, 0.95)], measles mumps rubella vaccine (MMR) [RR=0.71, 95% CI (0.61, 0.83)], or yellow fever vaccine [RR=0.70; 95% CI (0.59, 0.82)].

CONCLUSIONS

We did not find an increased risk of diagnosed type 1 diabetes and any of the study vaccines. We recommend that follow-up studies using medical record review to confirm case status should be considered to corroborate these findings.

EULAR recommendations for vaccination in paediatric patients with rheumatic diseases

Evidence-based recommendations for vaccination of paediatric patients with rheumatic diseases (PaedRD) were developed by following the EULAR standardised procedures for guideline development. The EULAR task force consisted of (paediatric) rheumatologists/immunologists, one expert in vaccine evaluation, one expert in public health and infectious disease control, and one epidemiologist. A systematic literature review was conducted in MEDLINE, EMBASE, and abstracts of the EULAR and American College of Rheumatology meetings of 2008/9. The level of evidence and strength of recommendation were based on customary scoring systems. Delphi voting was applied to assess the level of agreement between task force members. 107 papers and eight abstracts were used. The majority of papers considered seasonal influenza (41) or pneumococcal (23) vaccination. 26 studies were performed specifically in paediatric patients, and the majority in adult rheumatoid arthritis and systemic lupus erythematosus patients. Fifteen recommendations were developed with an overall agreement of 91.7%. More research is needed on the safety and immunogenicity of (live-attenuated) vaccination in PaedRD, particularly in those using biologicals, and the effect of vaccination on prevention of infections.

Autoimmune hepatitis type 2 following anti-papillomavirus vaccination in a 11-year-old girl

In the last years numerous reports describing a possible association between administration of vaccines and development of autoimmune phenomena and overt autoimmune disease were published. Possible mechanisms of induction of autoimmune phenomena by vaccines and their excipients are probably similar to those implicated in induction by infectious agents. Here we report the case of an 11-year-old girl who developed autoimmune hepatitis type II after four weeks from vaccination against human papillomavirus. The possible relationships between the use of adjuvated vaccine against papillomavirus and autoimmune hepatitis are discussed. Although we do not provide evidence for a causal link, we suggest that the occurrence of the autoimmune hepatitis may be related to the stimulation of immune system by adjuvated-vaccine, that could have triggered the disease in a genetically predisposed individual. Therefore a monitoring of liver function test following administration of vaccine against papillomavirus may be useful in adolescent girl with signs of hepatopathy, as jaundice, dark urine or hepatomegaly, to early identify and to promptly treat autoimmune liver disorders.

Immunizations and risk of multiple sclerosis: systematic review and meta-analysis

The role of vaccinations in risk of developing multiple sclerosis (MS) or in risk of relapse has not been well established. The aim of this study was to estimate the effect of immunizations on risk of developing MS in adults as well as in subsequent risk of relapse. Systematic search for publications in MEDLINE (1966-January 2011), EMBASE (1977-January 2011) and the Cochrane Central Register of Controlled Trials (CENTRAL) (1961-January 2011). Both randomized clinical trials and non-randomized studies addressing the effect of any Center for Diseases Control (CDC) recommended vaccine for children, adults or travelers and BCG on risk of MS or disease relapse were included. Two reviewers independently extracted information from articles selected using a predefined datasheet. No significant change in the risk of developing MS after vaccination was found for BCG (OR 0.96, 95% CI 0.69-1.34), Hepatitis B (OR 1.00, 95% CI 0.74-1.37), Influenza (OR 0.97, 95% CI 0.77-1.23), Measles-Mumps-Rubella (MMR) (OR 1.02, 95% CI 0.64-1.61), Polio (OR 0.87, 95% CI 0.61-1.25) and Typhoid fever (OR 1.05, 95% CI 0.72-1.53). We found decreased risk of developing MS for Diphtheria (OR 0.60, 95% CI 0.40-0.90) and Tetanus (OR 0.68, 95% CI 0.54-0.84). Influenza immunization was also associated with no change in risk of MS relapse (RR 1.24, 95% CI 0.89-1.72). Risk of developing multiple sclerosis remained unchanged after BCG, Hepatitis B, Influenza, MMR, Polio and Typhoid fever immunization, whereas diphtheria and tetanus vaccination may be associated with a decreased risk of MS. Further research is needed for the remaining vaccines.

[Infectious complications of biologic therapy in patients with rheumatoid arthritis]

The introduction of biological disease-modifying drugs (DMARDs) has substantially improved the treatment options for patients with rheumatoid arthritis. However, infectious complications represent the most common side effects of these drugs, including severe infections as well as rare opportunistic infections. Treating patients on biological DMARDs is therefore one of the biggest challenges in rheumatology care. The present review describes the current state of knowledge regarding frequency and type of infectious complications associated with biological DMARDs. The article focuses mainly on risk management, in particular on diagnosis and recurrence prevention of tuberculosis and reactivation of hepatitis B virus infection. Furthermore, we discuss the importance of vaccinations in primary disease prevention in patients with rheumatoid arthritis.

Vaccinations in patients with immune-mediated inflammatory diseases

Patients with immune-mediated inflammatory diseases (IMID) such as RA, IBD or psoriasis, are at increased risk of infection, partially because of the disease itself, but mostly because of treatment with immunomodulatory or immunosuppressive drugs. In spite of their elevated risk for vaccine-preventable disease, vaccination coverage in IMID patients is surprisingly low. This review summarizes current literature data on vaccine safety and efficacy in IMID patients treated with immunosuppressive or immunomodulatory drugs and formulates best-practice recommendations on vaccination in this population. Especially in the current era of biological therapies, including TNF-blocking agents, special consideration should be given to vaccination strategies in IMID patients. Clinical evidence indicates that immunization of IMID patients does not increase clinical or laboratory parameters of disease activity. Live vaccines are contraindicated in immunocompromized individuals, but non-live vaccines can safely be given. Although the reduced quality of the immune response in patients under immunotherapy may have a negative impact on vaccination efficacy in this population, adequate humoral response to vaccination in IMID patients has been demonstrated for hepatitis B, influenza and pneumococcal vaccination. Vaccination status is best checked and updated before the start of immunomodulatory therapy: live vaccines are not contraindicated at that time and inactivated vaccines elicit an optimal immune response in immunocompetent individuals.

Common vaccinations among adults do not increase the risk of developing rheumatoid arthritis: results from the Swedish EIRA study

OBJECTIVE

To investigate the association between vaccinations in adults and the risk of developing rheumatoid arthritis (RA).

METHODS

Data from the Swedish population-based Epidemiological Investigation of RA case-control study encompassing 1998 incident cases of RA aged 18-70 years and 2252 randomly selected controls matched for age, sex and residency were analysed. Those vaccinated within 5 years before disease onset were compared with those not vaccinated by calculating OR with 95% CI.

RESULTS

Vaccinations neither increased the risk of RA overall (OR 1.0, 95% CI 0.9 to 1.1) nor the risk of two major subgroups of RA (antibodies to citrullinated peptide-positive (ACPA-positive) and ACPA-negative disease). Furthermore, vaccinations did not increase the risk of RA in smokers or carriers of HLA-DRB1 shared epitope alleles, two groups with established risk factors for RA.

CONCLUSIONS

In this case-control study of incident cases of newly diagnosed RA, no increased risk of RA following immunisation was observed for vaccinations overall or for any specific vaccination. This indicates that immunological provocation of adults with commonly used vaccines in their present form carries no risk of RA. These findings should be implemented among public healthcare providers in order to encourage vaccinations according to recommended national vaccination schedules.

Autoimmune response following annual influenza vaccination in 92 apparently healthy adults

OBJECTIVE

To evaluate the possibility of autoimmune responses following annual influenza vaccination in a large cohort of apparently healthy adults.

METHODS

Autoantibodies including antinuclear antibodies (ANA), anticardiolipin antibodies (aCL), anti-beta(2)-glycoprotein I antibodies (anti-beta(2)-GPI), lupus anticoagulant (LA) and anti-extractable nuclear antigen antibodies (anti-ENA) were determined in 92 healthy adult subjects, staff at the University Children's Hospital Ljubljana. Blood samples were taken from each participant before the vaccination, 1 month and 6 months after the annual influenza vaccination.

RESULTS

Before the influenza vaccination, 26% of participants were positive for ANA, 16% for aCL, 7% for anti-beta(2)-GPI, 2% for LA and 1% for anti-ENA. There were no statistically significant differences in the percentage of positive ANA, aCL, anti-beta(2)-GPI, LA and anti-ENA before, 1 month and 6 months after the vaccination. One month after the vaccination 24% of participants demonstrated changes in the levels of autoantibodies including 15% of participants with increased level of autoantibodies or appearance of new autoantibodies. Six months after the vaccination 26% of participants demonstrated changes in the levels of autoantibodies including 13% of participants with increased level of autoantibodies or appearance of new autoantibodies. Persistently elevated levels of autoantibodies were observed in 7 (8%) participants and 2 showed progressively increased levels of IgM aCL or IgA anti-beta(2)-GPI, respectively. Eleven participants had a transient increase in autoantibodies.

DISCUSSION

Influenza vaccination in general did not alter the percentage of healthy adults with positive autoantibodies. Transiently or persistently increased levels of autoantibodies or appearance of new autoantibodies was demonstrated in up to 15% of apparently healthy adults after the influenza vaccination.

Vaccination and autoimmune rheumatic diseases

Patients with autoimmune rheumatic diseases are at increased risk of developing infections. However, concerns about the safety and the immunogenicity of vaccines in these patients limited their use. Most of the data against the use of vaccines come from the reported cases of previously healthy individuals who presented the onset of rheumatic diseases after immunization, nevertheless a causal relationship has not been established. During the past few decades influenza and pneumococcal vaccines, administered to patients with systemic lupus erythematosus, were found to be safe and, generally, serologically effective, even though there is the possibility of inadequate response, especially in patients receiving immunosuppressive agents. In patients with rheumatoid arthritis influenza and pneumococcal vaccines can be considered safe and immunogenic in most cases. Treatment with TNFalpha blocking agents did not appear to impair the immune response.

Systemic polyarteritis nodosa following hepatitis B vaccination

The authors report a patient who developed systemic polyarteritis nodosa two months after hepatitis B vaccination and review the literature concerning this vaccination and the development of autoimmune conditions, mainly vasculitis. A 14-year-old boy who had no relevant previous history and who was not taking any drugs presented with a livedo reticularis, fever, loss of weight, testicular pain, and paresthesias two months after receiving the third dose of a hepatitis B vaccination. Inflammatory parameters (ESR and CRP) were high. The patient met the ACR diagnostic criteria for polyarteritis nodosa. He received corticosteroids and immunosuppressants and showed improvement. After reviewing the 27 cases of vasculitis after hepatitis B vaccination reported in the current literature, the authors suggest that, in some cases, vaccination may be the triggering factor for vasculitis in individuals with a genetic predisposition. Physicians should be aware of this possible association.

Hepatitis B vaccine and risk of autoimmune thyroid disease: a Vaccine Safety Datalink study

PURPOSE

Hepatitis B vaccine has been postulated as a possible cause of autoimmune disorders, including autoimmune thyroid diseases (ATD). Cases of Graves' disease and Hashimoto's thyroiditis, following hepatitis B vaccine have been reported to the Vaccine Adverse Events Reporting System (VAERS). To test the hypothesis that hepatitis B vaccine increases the risk of ATD, we conducted a case-control study, within the Vaccine Safety Datalink project.

METHODS

We identified potential cases of Graves' disease and Hashimoto's thyroiditis, among persons aged 18-69 years from administrative data recorded by three health maintenance organizations (HMOs) and verified cases by medical record review. Controls were frequency-matched to cases by birth year, sex, and study site. Vaccine information was collected from administrative records, chart review, and telephone interviews with study subjects. We enrolled 355 Graves' disease cases, 418 Hashimoto's thyroiditis cases, and 1102 controls. We assessed the association between ever-receipt of hepatitis B vaccine, as well as receipt of hepatitis B vaccine less than 1 year, 1-5 years and at least 5 years prior to the index date, and the risk of ATD.

RESULTS

Ever-receipt of hepatitis B vaccine was not associated with risk of Graves' disease (odds ratio (OR), 0.90; 95% confidence interval (CI), 0.62-1.32) or Hashimoto's thyroiditis (OR, 1.23; 95%CI, 0.87-1.73). There was also no association between the time interval since receipt of hepatitis B vaccination and either outcome.

CONCLUSIONS

We did not observe an increased risk of Graves' disease or Hashimoto's thyroiditis, following receipt of hepatitis B vaccine.

Exacerbation of Lupus Panniculitis following Anti-Hepatitis-B Vaccination

Even though benefits of vaccination policies have been widely demonstrated, vaccine injections might be associated with rare side effects. In this setting, the potential role of vaccines, mostly against hepatitis B virus, in the induction of autoimmunity has been a matter of controversy. We report the case of a woman followed for a lupus panniculitis which had been in remission for 3 years, who developed a lupus flare following an anti-hepatitis-B vaccine injection. The topography of recurring lupus lesions, the chronology of the flare and the increase in the antinuclear autoantibody serum level all supported a causal role for vaccination in the relapse of the lupus lesions. We believe that the present case might provide a first observation of lupus panniculitis possibly induced by hepatitis B vaccination, and this should be added to the range of dysimmune manifestations caused by vaccinations.

Acute metabolic crisis induced by vaccination in seven Chinese patients

Seven Chinese patients (5 males and 2 females) with vaccination-induced acute metabolic crisis were reported. Only one male with 21-hydroxylase deficiency had been diagnosed before vaccination. In the remaining six patients, the preexisting diagnoses were not confirmed before the vaccination. Acute metabolic crisis occurred in seven patients between 3 and 12 hours after the administration of Japanese encephalitis, diphtheria, and tetanus toxoids and acellular pertussis, hepatitis B, or measles vaccines. Patients 1 and 2 displayed acute adrenal insufficiencies at the ages of 5 years and 3 months, respectively. Patient 3 had presented with mild motor retardation previously. Patients 4 to 7 were previously healthy, but suffered from fever, seizures, coma, acidosis, and hypoglycemia after being vaccinated. Glutaric aciduria type 1 was evident in case 4. Leigh syndromes were present in Patients 5, 6, and 7. They all died from respiratory failure before 2 years of age. Symmetric foci, cystic cavitations with neuronal loss, and vascular proliferation were observed by postmortem examination. Among the seven patients, although the vaccines were not the primary cause of the acute metabolic crisis, the severe acute episodes occurred coincidentally.

Vaccine side effects: fact and fiction

The debate over adverse reactions associated with companion animal vaccination has considerably exercised the veterinary profession internationally over the past decade. A range of suspected adverse reactions to vaccines is reported including the onset of inflammatory, allergic, autoimmune or neoplastic diseases. Lack of efficacy, interference with diagnostic testing and other occasional suspected product-related issues are also reported. Available data suggest that the overall prevalence of true adverse reactions is exceedingly low and that vaccination does not significantly contribute to ill-health in companion animals. There is increasing public interest in vaccination issues with transfer of focus from publicity over human vaccine side effects to those perceived to occur in animals. We must not lose sight of the fact that vaccination is a safe procedure that has impacted significantly on infectious disease control. Reduced population uptake of vaccination leads to re-emergence of disease in both humans and animals. Nevertheless, there have recently been a series of practical recommendations produced to ensure reduced 'vaccine load' on our companion animals and vaccine manufacturers are moving towards developing non-adjuvanted products with an extended duration of immunity. These measures will further reduce the very small current risk of any adverse consequences to vaccination in our pet population.

Bystander Immune Cytolysis

In addition to alloimmune and autoimmune cell lysis, a third category of immune destruction of blood cells should be recognized. This additional immunologic response occurs when cells or tissues are injured by immunologic reactions in which the cells act as "innocent bystanders." One mechanism by which an immune response to an exogenous antigen leads to the destruction of autologous blood cells is the temporary development of autoantibodies. This is actually an alloimmune reaction which results in a temporary state of "pseudo"-autoimmunity. Although originally described as a type of hemolysis of autologous cells, the concept of bystander immune cytolysis has been extended to include other instances in which immune destruction of cells is caused by antibody that is not developed in response to intrinsic antigens on the cell being lysed. In recent years, compelling data have been presented documenting bystander immune cytolysis in a number of different clinical settings, and efforts have been made to define the mechanisms by which this occurs. Physicians must be aware that some examples of immune lysis of autologous cells are, in reality, examples of temporary bystander immune cytolysis rather than true autoimmune disease. Furthermore, some alloimmune hemolytic reactions can result in lysis of bystander cells.

Management of Evans syndrome

Evans syndrome is an uncommon condition defined by the combination (either simultaneously or sequentially) of immune thrombocytopenia (ITP) and autoimmune haemolytic anaemia (AIHA) with a positive direct antiglobulin test (DAT) in the absence of known underlying aetiology. This condition generally runs a chronic course and is characterised by frequent exacerbations and remissions. First-line therapy is usually corticosteroids and/or intravenous immunoglobulin, to which most patients respond; however, relapse is frequent. Options for second-line therapy include immunosuppressive drugs, especially ciclosporin or mycophenolate mofetil; vincristine; danazol or a combination of these agents. More recently a small number of patients have been treated with rituximab, which induces remission in the majority although such responses are often sustained for <12 months and the long-term effects in children are unclear. Splenectomy may also be considered although long-term remissions are less frequent than in uncomplicated ITP. For very severe and refractory cases stem cell transplantation (SCT) offers the only chance of long-term cure. The limited data available suggest that allogeneic SCT may be superior to autologous SCT but both carry risks of severe morbidity and of transplant-related mortality. Cure following reduced-intensity conditioning has now been reported and should be considered for younger patients in the context of controlled clinical trials.

Évaluer le rapport bénéfices/risques de la vaccination contre l'hépatite B en France en 2006

PURPOSE

Rare and unexpected adverse events following hepatitis B immunization have been reported. This article aims to illustrate the risk-benefit assessment of hepatitis B immunization strategies, using the available evidence in medical literature.

CURRENT EVENTS

i) Hepatitis B vaccination efficacy is high in infants, children and adolescents. It may be lower in adults and at risk populations; ii) Hepatitis B descriptive epidemiological data in France are scarce, fragmental, unprecise and changing according to the studied population strata. The incidence of symptomatic cases in the general population is below 5 per 100,000 since the year 2000. In France, it is estimated that about 300,000 adults are carriers of HBs antigen, and thus able to transmit the disease; iii) The actual French pharmacovigilance signal and the epidemiological studies may suggest the hypothesis of an association between the occurrence of central nervous system demyelinating diseases and hepatitis B vaccination. If this association exists, the relative risk is probably of less than 3.

PERSPECTIVES

The lack of accuracy of risks estimates complicates the risk-benefit assessment of hepatitis B vaccination. Its perception is then influenced and distorted by subjective factors, underlying the need for research in communication about benefits and risks of immunizations. Although still debated, the hypothesis of a putative role of hepatitis B vaccine in the pathophysiology of demyelinating diseases should prompt to pursue experimental and epidemiological research to better understand the links between infectious environment and inflammatory chronic diseases.

Vaccine safety controversies and the future of vaccination programs

In the years following the hepatitis B vaccination/multiple sclerosis controversy, a number of new issues regarding vaccine safety have been raised, in some cases leading to more debate and confusion. Against this background, an international group of experts was convened to review the current points of view concerning the use of thimerosal as a preservative and its potential risks; the suggested link between thimerosal-containing vaccines and acute lymphoblastic leukemia; the alleged association between aluminum-containing vaccines/macrophagic myofasciitis and general systemic complaints; a possible link between vaccination and autoimmune pathology; and a hypothetical link between measles-mumps-rubella vaccination and autism. At present, there are no data to conclude that childhood vaccines, and in particular hepatitis B vaccine, pose a serious health risk or justify a change in current immunization practice. However, vaccine "scares" continue to have an international impact on immunization coverage. Creating a positive environment for immunization can be achieved by repositioning the value of vaccines and vaccination, supported by evidence-based information. The role of international organizations, the media, and the industry in the implementation of communication strategies was discussed and the impact of litigation issues on vaccination was evaluated. The Viral Hepatitis Prevention Board confirms its commitment to current recommendations for universal and risk group hepatitis B vaccination and further encourages the conduct of vaccine safety studies and the dissemination of their results.

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.

Autoimmunity, environmental exposure and vaccination: is there a link?

Although the wide clinical experience shows that vaccines are generally safe, concern has been expressed for a causal link between vaccines and autoimmune diseases. Even though the mechanisms of autoimmunity are ill-elucidated, the role of pre-existing risk factors including genetic predisposition and environmental factors is largely accepted. The present study was undertaken to test the hypothesis that vaccines can promote autoimmunity in genetically-prone individuals when simultaneously exposed to a chemical known to induce autoimmune reactions. Female lupus-prone (NZB x NZW) F(1) mice were given 1 microg or 10 microg of a hepatitis B vaccine at 2-week intervals in conjunction with 40 microg of mercuric chloride three times per week for 6 weeks. A marked increase in serum IgG levels and a slight increase in anti-nuclear autoantibody (ANA) levels were seen in the mice given 10 microg of the vaccine plus mercuric chloride. No straightforward conclusion can be drawn from these results because of the extreme experimental conditions of this study. Nevertheless, the results tend to support the hypothesis that vaccination could enhance the risk of autoimmunity in genetically susceptible individuals when exposed to certain environmental chemicals.

Comparative proteomics of the Mycobacterium leprae binding protein myelin P0: its implication in leprosy and other neurodegenerative diseases

Mycobacterium leprae, the causative agent of leprosy invades Schwann cells of the peripheral nerves leading to nerve damage and disfigurement, which is the hallmark of the disease. Wet experiments have shown that M. leprae binds to a major peripheral nerve protein, the myelin P zero (P0). This protein is specific to peripheral nerve and may be important in the initial step of M. leprae binding and invasion of Schwann cells which is the feature of leprosy. Though the receptors on Schawann cells, cytokines, chemokines and antibodies to M. leprae have been identified the molecular mechanism of nerve damage and neurodegeneration is not clearly defined. Recently pathogen and host protein/nucleotide sequence similarities (molecular mimicry) have been implicated in neurodegenerative diseases. The approach of the present study is to utilise bioinformatic tools to understand leprosy nerve damage by carrying out sequence and structural similarity searches of myelin P0 with leproma and other genomic database. Since myelin P0 is unique to peripheral nerve, its sequence and structural similarities in other neuropathogens have also been noted. Comparison of myelin P0 with the M. leprae proteins revealed two characterised proteins, Ferrodoxin NADP reductase and a conserved membrane protein, which showed similarity to the query sequence. Comparison with the entire genomic database (www.ncbi.nlm.nih.gov) by basic local alignment search tool for proteins (BLASTP) and fold classification of structure-structure alignment of proteins (FSSP) searches revealed that myelin P0 had sequence/structural similarities to the poliovirus receptor, coxsackie-adenovirus receptor, anthrax protective antigen, diphtheria toxin, herpes simplex virus, HIV gag-1 peptide, and gp120 among others. These proteins are known to be associated directly or indirectly with neruodegeneration. Sequence and structural similarities to the immunoglobin regions of myelin P0 could have implications in host-pathogen interactions, as it has homophilic adhesive properties. Although these observed similarities are not highly significant in their percentage identity, they could be functionally important in molecular mimicry, receptor binding and cell signaling events involved in neurodegeneration.

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.

Effects of various adjuvants and a viral infection on the antibody specificity toward native or cryptic epitopes of a protein antigen

An immunization protocol that induces antibodies (Abs) directed to cryptic epitopes of a protein antigen (Ag) reduces the efficacy of vaccines that ideally should induce Abs against native epitopes. We have shown earlier that viral infections concomitant with immunization against a protein tend to shift the Ab specificity toward cryptic epitopes and tend to induce the production of autoantibodies (autoAbs). Here, we show the effects of three adjuvants on the Ab specificity in the absence or presence of a viral infection (lactate dehydrogenase-elevating virus or LDV), with human growth hormone (hGH) being, as before, the protein Ag. Pathogen-free CBA/Ht and BALB/c mice were immunized with hGH in the presence of complete Freund's adjuvant (CFA), monophosphoryl lipid A (MPL) or alum, with the animals being either infected with LDV or not infected with LDV. Conventional and competition enzyme-linked immunosorbent assays (ELISAs) indicated that in noninfected mice, CFA induced higher titres of anti-hGH Ab than did MPL or alum, with the Ab being almost totally directed to cryptic hGH epitopes. Strikingly, CFA plus LDV infection in CBA/Ht mice shifted the specificity of the anti-hGH Ab toward native epitopes, whereas the virus decreased the Ab titre when MPL or alum was used. Our Western blot results showed that 70% of mice immunized with hGH in the presence of any adjuvant produced autoAbs against a variety of tissue Ags. The amount of autoAb and the concentration of Ab to hGH cryptic epitopes did correlate, suggesting a relationship between both kinds of Ab. Significant differences were observed in the various effects of adjuvants and the viral infection between the two mouse strains used in this work.

Antivaccination activists on the world wide web

AIMS

To determine the likelihood of finding an antivaccination site on the world wide web and to characterise their explicit claims and rhetorical appeals.

METHODS

Using "vaccination" and "immunisation", examining the first 10 sites displayed on seven leading search engines. Detailed examination of content of 100 antivaccination sites found on Google.

RESULTS

43% of websites were antivaccination (all of the first 10 on Google). Main rhetorical appeals involve themes of the scientific veracity of antivaccination argument; rapport with parents seeking to protect their children from harm; and alleged collusion between doctors, the pharmaceutical industry, and government to deny vaccine harm.

CONCLUSIONS

There is a high probability that parents will encounter elaborate antivaccination material on the world wide web. Factual refutational strategies alone are unlikely to counter the highly rhetorical appeals that shape these sites.