Association between type 1 diabetes and Haemophilus influenzae type b vaccination: birth cohort study

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.

Childhood Vaccinations and Type 1 Diabetes

Type 1 diabetes (T1D) is the most common paediatric endocrine disease, and its frequency has been found to increase worldwide. Similar to all conditions associated with poorly regulated glucose metabolism, T1D carries an increased risk of infection. Consequently, careful compliance by T1D children with schedules officially approved for child immunization is strongly recommended. However, because patients with T1D show persistent and profound limitations in immune function, vaccines may evoke a less efficient immune response, with corresponding lower protection. Moreover, T1D is an autoimmune condition that develops in genetically susceptible individuals and some data regarding T1D triggering factors appear to indicate that infections, mainly those due to viruses, play a major role. Accordingly, the use of viral live attenuated vaccines is being debated. In this narrative review, we discussed the most effective and safe use of vaccines in patients at risk of or with overt T1D. Literature analysis showed that several problems related to the use of vaccines in children with T1D have not been completely resolved. There are few studies regarding the immunogenicity and efficacy of vaccines in T1D children, and the need for different immunization schedules has not been precisely established. Fortunately, the previous presumed relationship between vaccine administration and T1D appears to have been debunked, though some doubts regarding rotavirus vaccines remain. Further studies are needed to completely resolve the problems related to vaccine administration in T1D patients. In the meantime, the use of vaccines remains extensively recommended in children with this disease.

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.

Side Effects of Vaccination: A Consumer's Guide to Cause and Effect

Credit

This lesson is good for 0.2 CE units, with a passing grade of 70%.

Objectives

1. To describe historical examples of adverse events truly and spuriously associated with vaccination. 2. To describe a rational basis for deciding whether adverse events are causally or coincidentally linked to a medication. 3. To demonstrate how to apply this rational basis to a variety of exposure—outcome associations.

Side Effects of Vaccination: A Consumer's Guide to Cause and Effect

Credit

This lesson is good for 0.2 CE units, with a passing grade of 70%.

Objectives

1. To describe historical examples of adverse events truly and spuriously associated with vaccination. 2. To describe a rational basis for deciding whether adverse events are causally or coincidentally linked to a medication. 3. To demonstrate how to apply this rational basis to a variety of exposure—outcome associations.

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.

Vaccinations and childhood type 1 diabetes mellitus: a meta-analysis of observational studies

AIMS/HYPOTHESIS

The aim of this study was to investigate the association between routine vaccinations and the risk of childhood type 1 diabetes mellitus by systematically reviewing the published literature and performing meta-analyses where possible.

METHODS

A comprehensive literature search was performed of MEDLINE and EMBASE to identify all studies that compared vaccination rates in children who subsequently developed type 1 diabetes mellitus and in control children. ORs and 95% CIs were obtained from published reports or derived from individual patient data and then combined using a random effects meta-analysis.

RESULTS

In total, 23 studies investigating 16 vaccinations met the inclusion criteria. Eleven of these contributed to meta-analyses which included data from between 359 and 11,828 childhood diabetes cases. Overall, there was no evidence to suggest an association between any of the childhood vaccinations investigated and type 1 diabetes mellitus. The pooled ORs ranged from 0.58 (95% CI 0.24, 1.40) for the measles, mumps and rubella (MMR) vaccination in five studies up to 1.04 (95% CI 0.94, 1.14) for the haemophilus influenza B (HiB) vaccination in 11 studies. Significant heterogeneity was present in most of the pooled analyses, but was markedly reduced when analyses were restricted to study reports with high methodology quality scores. Neither this restriction by quality nor the original authors' adjustments for potential confounding made a substantial difference to the pooled ORs.

CONCLUSIONS/INTERPRETATION

This study provides no evidence of an association between routine vaccinations and childhood type 1 diabetes.

The role of Toll-like receptors and vitamin D in diabetes mellitus type 1--a review

It is widely accepted that type 1 diabetes mellitus (T1DM) is an autoimmune disease resulting from an interaction between immunologic, genetic and environmental factors. However, the exact mechanism leading to the development of T1DM remains incomplete. There is a large body of evidence pointing towards the important role of toll-like receptor (TLR) activation and vitamin D deficiency in T1DM pathogenesis. In this article, we review the available data on the influence of TLRs' level of activation and vitamin D status on the risk of the development of T1DM in humans and rodent models. We also summarize the current information regarding the interactions between TLRs' level of activation, vitamin D status and various environmental factors, such as enteroviral infections, the gut microbiota and breastfeeding substitution, among others. Our results stipulate that vitamin D seems to protect against T1DM by reducing the TLRs' level of activation.

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.

Neurological and autoimmune disorders after vaccination against pandemic influenza A (H1N1) with a monovalent adjuvanted vaccine: population based cohort study in Stockholm, Sweden

OBJECTIVE

To examine the risk of neurological and autoimmune disorders of special interest in people vaccinated against pandemic influenza A (H1N1) with Pandemrix (GlaxoSmithKline, Middlesex, UK) compared with unvaccinated people over 8-10 months.

DESIGN

Retrospective cohort study linking individualised data on pandemic vaccinations to an inpatient and specialist database on healthcare utilisation in Stockholm county for follow-up during and after the pandemic period.

SETTING

Stockholm county, Sweden. Population All people registered in Stockholm county on 1 October 2009 and who had lived in this region since 1 January 1998; 1,024,019 were vaccinated against H1N1 and 921,005 remained unvaccinated.

MAIN OUTCOME MEASURES

Neurological and autoimmune diagnoses according to the European Medicines Agency strategy for monitoring of adverse events of special interest defined using ICD-10 codes for Guillain-Barré syndrome, Bell's palsy, multiple sclerosis, polyneuropathy, anaesthesia or hypoaesthesia, paraesthesia, narcolepsy (added), and autoimmune conditions such as rheumatoid arthritis, inflammatory bowel disease, and type 1 diabetes; and short term mortality according to vaccination status.

RESULTS

Excess risks among vaccinated compared with unvaccinated people were of low magnitude for Bell's palsy (hazard ratio 1.25, 95% confidence interval 1.06 to 1.48) and paraesthesia (1.11, 1.00 to 1.23) after adjustment for age, sex, socioeconomic status, and healthcare utilisation. Risks for Guillain-Barré syndrome, multiple sclerosis, type 1 diabetes, and rheumatoid arthritis remained unchanged. The risks of paraesthesia and inflammatory bowel disease among those vaccinated in the early phase (within 45 days from 1 October 2009) of the vaccination campaign were significantly increased; the risk being increased within the first six weeks after vaccination. Those vaccinated in the early phase were at a slightly reduced risk of death than those who were unvaccinated (0.94, 0.91 to 0.98), whereas those vaccinated in the late phase had an overall reduced mortality (0.68, 0.64 to 0.71). These associations could be real or explained, partly or entirely, by residual confounding.

CONCLUSIONS

Results for the safety of Pandemrix over 8-10 months of follow-up were reassuring -notably, no change in the risk for Guillain-Barré syndrome, multiple sclerosis, type 1 diabetes, or rheumatoid arthritis. Relative risks were significantly increased for Bell's palsy, paraesthesia, and inflammatory bowel disease after vaccination, predominantly in the early phase of the vaccination campaign. Small numbers of children and adolescents with narcolepsy precluded any meaningful conclusions.

The multi-systemic nature of diabetes mellitus: Genotype or phenotype?

BACKGROUND

This article discusses factors which materially influence the diagnosis, prevention and treatment of diabetes mellitus but which may be overlooked by the prevailing biomedical paradigm. That cognition can be mathematically linked to the function of the autonomic nervous system and physiological systems casts new light upon the mechanisms responsible for homeostasis and origins of disease. In particular, it highlights the limitations of the reductionist biomedical approach which considers mainly the biochemistry of single pathologies rather than considering the neural mechanisms which regulate the function of physiological systems, and inherent visceral organs; and which are subsequently manifest as biochemistries of varying degrees of complexity and severity. As a consequence, histopathological tests are fraught with inherent limitations and many categories of drugs are significantly ineffective.

AIMS

Such limitations may be explained if disease (in particular diabetes mellitus) has multiple origins, is multi-systemic in nature and, depending upon the characteristics of each pathology, is influenced by genotype and/or phenotype.

RESULTS

This article highlights the influence of factors which are not yet considered re. the aetiology of diabetes mellitus e.g. the influence of light and sensory input upon the stability of the autonomic nervous system; the influence of raised plasma viscosity upon rates of reaction; the influence of viruses and/or of modified live viruses given in vaccinations; systemic instability, in particular the adverse influence of drinks and lack of exercise upon the body's prevailing pH and its subsequent influence upon levels of magnesium and other essential trace elements.

CONCLUSIONS

This application of the top-down systems biology approach may provide a plausible and inclusive explanation for the nature and occurrence of diabetes mellitus.

The rising incidence of type 1 diabetes mellitus and the role of environmental factors--three decade experience in a primary care health center in Saudi Arabia

BACKGROUND

The incidence of type 1 diabetes has been increasing all over the world including Saudi Arabia and environmental factors have been suggested to play an important role in its etiology.

OBJECTIVE

The aim of this study was to evaluate if there are any contributory roles of various environmental factors in the rising incidence of type 1 diabetes in children in the Eastern Province of Saudi Arabia.

METHODS

We conducted a retrospective study of Saudi Arab subjects (n = 119) diagnosed between 1980 and 2009 with type 1 diabetes and these subjects were classified to six groups on the basis of the onset of diabetes.

RESULTS

119 subjects (61 boys and 58 girls) with confirmed diagnosis of type 1 diabetes met the study eligibility criteria. 89 children (74%) presented with ketoacidosis. The mean age of onset was 4 3/4 years for Group II and age of onset increased to above 8 years on subsequent years. Excessive weight gain was noted in all study groups. No etiological influences of maternal age at birth, birth order, birth weight, early introduction of cow's milk and cereals, infections and vaccines as well as nitrate levels in drinking water were noted in any of the groups. The predicted doubling of diabetes in young children below 5 years as in previous studies was not found in our study.

CONCLUSIONS

The rising incidence of type 1 diabetes over the last 30 years is not proved to have been influenced by various environmental factors.

Vaccination safety update

INTRODUCTION

In Germany, a large number of biased reports against vaccination have recently been published in all of the news media, and particularly on the internet. This paper discusses the safety profile of modern vaccines and their continuous surveillance and shows why the current criticism of vaccination on safety grounds is unjustified.

METHODS

The authors have performed a selective literature search to enable a proper distinction to be drawn between scientifically justified and unjustified reports on the potential adverse effects of vaccination.

RESULTS

At present, the safety of a new vaccine must be demonstrated in large-scale clinical trials before the product is licensed. After licensing, the safety of new vaccines is constantly monitored, and the results of monitoring are published.

DISCUSSION

An examination of these data reveals that the expressed doubts about the safety of vaccines are unjustified.

No association between routinely recorded infections in early life and subsequent risk of childhood-onset Type 1 diabetes: a matched case-control study using the UK General Practice Research Database

AIMS

To determine whether children with infections in early life (recorded routinely in general practice) have a reduced risk of Type 1 diabetes, as would be expected from the hygiene hypothesis.

METHODS

Children with Type 1 diabetes and up to 20 matched (on year of birth, sex and region) control subjects were selected from a cohort of children born in the UK at General Practice Research Database practices. For each child, the frequency of general practitioner consultations for infections and prescriptions for antibiotics in the first year of life were determined. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated using conditional logistic regression.

RESULTS

The main analysis included 367 case and 4579 matched control subjects. There was no evidence of any reduction in the subsequent risk of Type 1 diabetes in children with at least one infection in the first year of life (OR = 1.03, 95%CI 0.79, 1.34) or in children prescribed antibiotics in the first year of life (OR = 1.03, 95%CI 0.82, 1.29). Further analyses also revealed little evidence of a difference in subsequent risk of Type 1 diabetes after different types of infection in the first year of life (including gastrointestinal, conjunctivitis, otitis media and upper and lower respiratory tract). Analyses of infections in the first 2 years of life reached similar conclusions.

CONCLUSIONS

This study provides no evidence of an association between infections in early life and subsequent risk of childhood-onset Type 1 diabetes and therefore does not support the hygiene hypothesis.

Pharmacovigilance des vaccins

Safety of vaccines must be excellent to make vaccine's strategy acceptable, since it usually has a deferred individual benefit but immediate adverse drug reactions (ADRs). Pharmacovigilance of vaccines after their marketing is crucial because, prior to its availability on the market, the size of clinical trials is insufficient to identify rare or deferred adverse effects. The Pharmacovigilance is based on "spontaneous reporting" of ADRs to the Pharmacovigilance Regional Centre (PVRC) which establishes a relationship between each drug taken by the patient and the ADRs occurrence (imputability). This method is crucial to generate alerts, but under-estimates the real frequency of ADRs (1 to 10% of severe ADRs are reported). Thus pharmacoepidemiology studies are necessary to confirm the alerts identified by spontaneous reporting. ADRs can be specific, related to the antigen of an attenuated alive virus vaccine (lymphocyte meningitis after anti-mumps vaccine) or non-specific, related to a component different from the antigen (aluminium hydroxide involved in the "macrophagic myofasciitis", allergic reactions to neomycin, latex, egg or gelatine). Importance of Pharmacovigilance of vaccines is illustrated. Data, especially case-control studies, about the relationship between multiple sclerosis and hepatitis B vaccine are summarised. Data about the relationship between Crohn's disease or autism and MMR vaccine are analysed. As vaccines are used in healthy people, their safety must be excellent to be accepted. To monitor them after their marketing is the unique way to detect rare ADRs. This surveillance is made through reporting of ADRs to the PVRC. However, an active and intensive surveillance of ADRs as the one set up from the marketing of Prevenar should be systematic.

Evaluating the safety of new vaccines: summary of a workshop

Public concerns about the safety of vaccines arise on a regular basis. In November 2000, a workshop titled "Evaluation of New Vaccines: How Much Safety Data?" was convened by US Public Health Service agencies, including the Food and Drug Administration, the National Institutes of Health, the Centers for Disease Control and Prevention, and the Health Resources and Services Administration, to discuss appropriate methods for evaluating the safety of new vaccines. Workshop presentations addressed the current standards and approaches for new vaccine evaluation and postlicensure surveillance, as well as public views about vaccine safety and alternative approaches that could be considered. The advantages and disadvantages of conducting large controlled trials before licensure or widespread use of a new vaccine were discussed. We summarize these presentations and discussions.

Vaccines and immunotherapies for the prevention of infectious diseases having cutaneous manifestations

Although the development of antimicrobial drugs has advanced rapidly in the past several years, such agents act against only certain groups of microbes and are associated with increasing rates of resistance. These limitations of treatment force physicians to continue to rely on prevention, which is more effective and cost-effective than therapy. From the use of the smallpox vaccine by Jenner in the 1700s to the current concerns about biologic warfare, the technology for vaccine development has seen numerous advances. The currently available vaccines for viral illnesses include Dryvax for smallpox; the combination measles, mumps, and rubella vaccine; inactivated vaccine for hepatitis A; plasma-derived vaccine for hepatitis B; and the live attenuated Oka strain vaccine for varicella zoster. Vaccines available against bacterial illnesses include those for anthrax, Haemophilus influenzae, and Neisseria meningitidis. Currently in development for both prophylactic and therapeutic purposes are vaccines for HIV, herpes simplex virus, and human papillomavirus. Other vaccines being investigated for prevention are those for cytomegalovirus, respiratory syncytial virus, parainfluenza virus, hepatitis C, and dengue fever, among many others. Fungal and protozoan diseases are also subjects of vaccine research. Among immunoglobulins approved for prophylactic and therapeutic use are those against cytomegalovirus, hepatitis A and B, measles, rabies, and tetanus. With this progress, it is hoped that effective vaccines soon will be developed for many more infectious diseases with cutaneous manifestations.

Factors influencing the uptake of childhood immunisation in rural areas

BACKGROUND

Childhood vaccination has been vigorously debated in recent years. Professional and parental confidence in the measles, mumps and rubella (MMR) vaccine in particular has been shaken, as reflected by its decreased uptake.

AIM

To investigate the influence of practice type and the method of vaccination call/recall on childhood immunisation coverage.

DESIGN

Analysis of childhood immunisation uptake rates.

SETTING

General practices in the Highland NHS Health Board area in Scotland.

METHOD

Data on the immunisation uptake of individual practices in the region were obtained from the Information and Statistics Division of NHS Scotland.

RESULTS

Uptake of all vaccines in children reaching the age of 2 years was lower in practices using their own call/recall system than those engaged with the national system. Inducement practices achieved lower uptake than non-inducement practices for every immunisation studied, with the differences ranging from 4.7% to 7.8%. Compared with group practices, uptake of all vaccines was less for single-handed practices, with the differences ranging from 2.4% to 11.4%. A logistic regression analysis found that high uptake of the diphtheria and meningococcus group C vaccines by the age of 24 months was significantly associated with use of the national call/recall system. Only inducement practice status was significantly associated with reduced uptake in children aged 12 months.

CONCLUSIONS

Engagement with the national call/recall system was associated with higher immunisation coverage for children reaching the age of 2 years. Inducement status was associated with low uptake of vaccinations in children reaching the age of 1 year.

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.

Vaccinations May Induce Diabetes-Related Autoantibodies in One-Year-Old Children

Vaccinations have been discussed as one among many environmental candidates contributing to the immune process that later may lead to type 1 diabetes. ABIS (All Babies in Southeast Sweden) is a prospective cohort study following a nonselected birth cohort of general population. In a randomly selected sample collection from 4400 children, GADA and IA-2A have been determined at the age of 1 year. The information on vaccinations was collected from questionnaires answered by the parents and was related to beta cell autoantibodies. When studying the induction of autoantibodies using the autoantibody level of 90th percentile as cutoff level, hemophilus influenza B (HIB) vaccination appeared to be a risk factor for IA-2A [OR 5.9 (CI 1.4-24.4; p = 0.01)] and for GADA [OR 3.4 (CI 1.1-10.8; p = 0.04)] in logistic regression analyses. Furthermore, the titers of IA-2A were significantly higher (p < 0.01 in Mann-Whitney test) in those children who had got HIB vaccination. When 99th percentile was used as cutoff to identify the children at risk of type 1 diabetes, BCG vaccination was associated with increased prevalence of IA-2A (p < 0.01). We conclude that HIB vaccination may have an unspecific stimulatory polyclonal effect increasing the production of GADA and IA-2A. This might be of importance under circumstances when the beta cell-related immune response is activated by other mechanisms.

Immunizations, neonatal jaundice, and animal-induced injuries

This article reviews recent advances and recommendation changes in the areas of immunization, neonatal hyperbilirubinemia, and animal-induced injury. Physician education of families and care of patients in these three topic areas are important public health measures. First, pediatricians are always actively promoting public health through immunization, so the 2003 vaccination recommendations are critiqued along with perceived barriers to proper immunization. New information about smallpox vaccine is included in this year's review because of increased concerns about the use of smallpox as a weapon of bioterrorism since the world events in recent years. Next, the continued study of the management of hyperbilirubinemia in preventing kernicterus is examined. Finally, the management and prevention of animal-induced injuries is reviewed. In each of these areas, the pediatrician plays a prominent role in promoting the health and well being of children.

Safety of immunisation and adverse events following vaccination against hepatitis B

Hepatitis B vaccines (HBVs) are composed of highly purified preparations of hepatitis B virus surface antigen (HBsAg). An adjuvant, either aluminium phosphate or aluminium hydroxide, is added to the vaccines, which are sometimes preserved with thiomersal. In placebo-controlled studies, common side effects other than local reactions were reported no more frequently among vaccine recipients than among individuals receiving a placebo. A number of controversial adverse events have, however, been purported to be associated with HBVs, including rheumatoid arthritis (RA), diabetes, demyelinating diseases (e.g., multiple sclerosis [MS]), chronic fatigue syndrome, and more recently, lymphoblastic leukaemia. In addition, the safety of the thiomersal and aluminium contained in the vaccine has also been under close scrutiny. These issues have been reviewed by a number of country-specific or international independent review committees such as that of the US Institute of Medicine (IOM) and the World Health Organization's (WHO) Global Advisory Committee on Vaccine Safety (GACVS). Upon review of the scientific evidence, none of the serious allegations have so far been confirmed. On the contrary, scientific evidence has accumulated to disprove many of the allegations. In particular, the IOM committee has concluded that the evidence favoured rejection of a causal relationship between HBV administered to adults and incident MS or MS relapse. Whilst it is important to continue monitoring some of the safety issues, there is no evidence to suggest that the WHO should consider altering its recommendation that all countries should have universal infant and/or adolescent immunisation programmes. The risks of hepatitis B vaccination are only theoretical in comparison with clear benefits in terms of cirrhosis and cancer prevention, and the HBV remains one with an excellent safety profile.

The science of evaluation of adverse events associated with vaccination

All vaccines cause some adverse events; serious adverse events are rare. Causal associations between a vaccine and an adverse event rarely can be determined by specific tests such as identifying a vaccine agent in the affected tissue of patients. In the absence of such data, epidemiologic studies can be used to determine if the risk of the disorder is increased in vaccinated compared to unvaccinated individuals. Common mistakes include assuming a causal relationship based on a temporal association only or a series of affected patients. Careful studies have demonstrated that many hypothesized causal associations between vaccines and adverse events were not substantiated. False assumptions regarding causality are likely to occur for illnesses without a carefully defined etiology or pathogenesis.

Lack of association between receipt of conjugate haemophilus influenzae type B vaccine (HbOC) in infancy and risk of type 1 (juvenile onset) diabetes: long term follow-up of the HbOC efficacy trial cohort

We evaluated the effect of infant vaccination with HbOC Haemophilus influenzae type b (Hib) conjugate vaccine on the risk of onset of type 1 juvenile diabetes later in life by examining data from a large controlled prospective Phase III clinical efficacy trial conducted within Northern California Kaiser Permanente between 1988 and 1990. The overall study population included children who were offered the Hib conjugate vaccine (acceptors and refusers) as well as a cohort of children who were systemically excluded from the trial on the basis of their birth date. These children are now 10 to 12 years of age. We found no evidence that vaccination with Hib conjugate vaccine in infancy is associated with risk of diabetes later in life.

Challenges to vaccine safety

The end of the 20th century saw the realization of a goal that was previously only dreamed about: the near elimination of many deadly infectious diseases through universal vaccination. As one disease after another has been driven from memory, it is vaccination programs themselves that have come to occupy the public's mind. With increased scrutiny comes the promise that vaccines will become even safer, but there is also the threat that ill-founded concerns will result in reduced immunization rates, and diseases will resurge. This article reviews scientific data relating to current vaccine safety concerns.

Childhood vaccinations, vaccination timing, and risk of type 1 diabetes mellitus

OBJECTIVES

To evaluate suggested associations between childhood vaccinations, particularly against hepatitis B and Haemophilus influenzae type b, and risk of developing type 1 diabetes; and to determine whether timing of vaccination influences risk.

METHODS

We conducted a case-control study within 4 health maintenance organizations (HMOs) that participate in the Vaccine Safety Datalink project of the Centers for Disease Control and Prevention. Study eligibility was restricted to children who met the following criteria: 1) born during 1988 through 1997; 2) HMO member since birth; 3) continuously enrolled for first 6 months of life; and 4) at least 12 months of HMO membership before diabetes incidence date (or index date for controls) unless incidence date was before 12 months of age. All 4 HMOs maintain registries of their members who have diabetes, and we used the registries to identify potential cases of diabetes. We conducted chart reviews to verify that potential cases met the World Health Organization epidemiologic case definition for type 1 diabetes mellitus (ie, a physician's diagnosis of diabetes plus treatment with daily insulin injections). We defined the incidence date of diabetes as the first date that the child received a diagnosis of diabetes. We attempted to match 3 controls to each case. Controls had the same eligibility criteria as cases and were matched to individual cases on HMO, sex, date of birth (within 7 days), and length of health plan enrollment (up to the incidence or index date). The index date for controls was defined as the incidence date of the case to which the control was matched. Chart abstraction was performed by trained chart abstractors using standardized forms. In addition to complete vaccination histories, the chart abstraction forms for both cases and controls included information on sociodemographic characteristics, selected medical conditions, history of breastfeeding, and family medical history. We used conditional logistic regression to estimate the odds ratio (OR) of diabetes associated with vaccination, with vaccine exposure defined as before the diabetes incidence date (or index date for controls).

RESULTS

Two hundred fifty-two confirmed cases of diabetes and 768 matched controls met the study eligibility criteria. The OR (95% confidence interval) for the association with type 1 diabetes was 0.28 (0.07-1.06) for whole cell pertussis vaccine (predominantly in combination as diphtheria, tetanus toxoids and pertussis vaccine), 1.36 (0.70-2.63) for measles-mumps-rubella, 1.14 (0.51-2.57) for Haemophilus influenzae type b, 0.81 (0.52-1.27) for hepatitis B vaccine, 1.16 (0.72-1.89) for varicella vaccine, and 0.92 (0.53-1.57) for acellular pertussis-containing vaccines. Compared with children who had not received hepatitis B vaccine, the OR of diabetes was 0.51 (0.23-1.15) for children vaccinated at birth and 0.86 (0.54-1.35) for those first vaccinated against hepatitis B at 2 months of age or later. Race and ethnicity and family history of diabetes were independently associated with risk of type 1 diabetes, but adjustment for these factors did not materially alter the ORs for any of the vaccines.

CONCLUSIONS

In this large, population-based, case-control study, we did not find an increased risk of type 1 diabetes associated with any of the routinely recommended childhood vaccines. Our study adds to previous research by providing data on newer vaccines, including hepatitis B, acellular pertussis, and varicella vaccines. For the older vaccines, our results are generally in agreement with previous studies in not finding any increased risks. Ours is the first epidemiologic study to evaluate the possibility that timing of vaccination is related to risk of clinical diabetes in children. Our results on hepatitis B vaccine do not support the hypothesis; risk of type 1 diabetes was not different between infants vaccinated at birth and those who received their first vaccination later in life. The results of our study and the preponderance of epidemiologic evidence do not support an association between any of the recommended childhood vaccines and an increased risk of type 1 diabetes. Suggestions that diabetes risk in humans may be altered by changes in the timing of vaccinations also are unfounded.

A combination vaccine confers full protection against co-infections with influenza, herpes simplex and respiratory syncytial viruses

Combined/composite vaccines should be useful in reducing the number of vaccinations and provide more flexibility in confronting biological warfare scenarios. We tested the effectiveness of a composite genetic vaccine designed from previously known protective antigens directed against influenza A virus (INF-A), herpes simplex virus type-1 (HSV-1) and respiratory syncytial virus (RSV) in a mouse-based challenge. Immunizing mice with a pool of four plasmids; INF-A haemagglutinin (HA), INF-A nucleoprotein (NP), HSV-1 glycoprotein D (gD) and RSV glycoprotein F, against the three pathogens provided full protection when mice were challenged with each pathogen. Remarkably, mice challenged with all three pathogens at once were also fully protected, even when a bacterial pathogen, Mycoplasma pulmonis, was included in the challenge. If these results are extendable to other combinations of vaccines in other hosts, it would support the development of gene vaccines as multi-component, combination vaccines.

Lessons learned concerning vaccine safety

The safety of vaccines is an issue that has been with us ever since Jenner, and it will not go away. The author argues that despite what may seem a waste of energy, most proposed relationships between vaccines and reactions must be thoroughly investigated, as some have been proved correct. Investigations that show the putative relationship to be incorrect serve as examples of scientific rigor, which are valuable for the public. The author draws eight lessons for the future from our recent experiences.

Active immunization in the United States: developments over the past decade

The Centers for Disease Control and Prevention has identified immunization as the most important public health advance of the 20th century. The purpose of this article is to review the changes that have taken place in active immunization in the United States over the past decade. Since 1990, new vaccines have become available to prevent five infectious diseases: varicella, rotavirus, hepatitis A, Lyme disease, and Japanese encephalitis virus infection. Improved vaccines have been developed to prevent Haemophilus influenzae type b, pneumococcus, pertussis, rabies, and typhoid infections. Immunization strategies for the prevention of hepatitis B, measles, meningococcal infections, and poliomyelitis have changed as a result of the changing epidemiology of these diseases. Combination vaccines are being developed to facilitate the delivery of multiple antigens, and improved vaccines are under development for cholera, influenza, and meningococcal disease. Major advances in molecular biology have enabled scientists to devise new approaches to the development of vaccines against diseases ranging from respiratory viral to enteric bacterial infections that continue to plague the world's population.

Epidemiology of autoimmune reactions induced by vaccination

In order for vaccinations to 'work', the immune system must be stimulated. The concern that immunizations may lead to the development of autoimmune disease (AID) has been questioned. Since AID occur in the absence of immunizations, it is unlikely that immunizations are a major cause of AID. Epidemiological studies are needed, however, to assess whether immunizations may increase the risk in some susceptible individuals. This paper discusses the evidence for and against vaccination as a risk factor for AID. Evidence for immunizations leading to AID come from several sources including animal studies, single and multiple case reports, and ecologic association. However more rigorous investigation has failed to confirm most of the allegations. Unfortunately the question remains difficult to address because for most AIDs, there is limited knowledge of the etiology, background incidence and other risk factors for their development. This information is necessary, in the absence of experimental evidence derived from controlled studies, for any sort of adequate causality assessment using the limited data that are available. Several illustrative examples are discussed to highlight what is known and what remains to be explored, and the type of epidemiological evidence that would be required to better address the issues. Examples include the possible association of immunization and multiple sclerosis (and other demyelinating diseases), type 1 diabetes mellitus, Guillain-Barre Syndrome, idiopathic thrombocytopenic purpura, and rheumatoid arthritis.

Type 1A diabetes induced by infection and immunization

Type 1A diabetes is an immune mediated disorder that results from progressive destruction of the islet beta-cells in the setting of genetic susceptibility. Both MHC and non-MHC genes contribute to disease with class II HLA molecules major determinants of susceptibility or protection. The presence of multiple anti-islet autoantibodies is associated with a high risk of disease progression, and the first anti-islet autoantibodies may appear as early as the first year of life. Congenital rubella is the only infection clearly associated with the development of type 1A diabetes. With the ability to detect children in the first year of life activating autoimmunity, prospective studies may in the future document additional environmental factors either increasing or decreasing diabetes risk.

Adverse events and vaccination-the lack of power and predictability of infrequent events in pre-licensure study

The recent setback in the development of a safe and effective rotavirus vaccine illustrates an important problem regarding prelicensure testing and its ability to identify rare vaccine-related adverse effects. It is our contention that the possibility of a rare but serious vaccine adverse effect is difficult to detect in prelicensure testing. In this paper, we review the history regarding the testing and eventual studies that led to the permanent withdrawal of that vaccine. The post-licensure discovery of a serious adverse event associated with the rotavirus vaccine is not unique among vaccines, but represents a recurrent phenomenon that in fact is mathematically predictable. Prelicensure studies examine thousands of subjects and not hundreds of thousands. A sample size of 10,000 subjects may provide excellent estimates of efficacy, but cannot provide an adequate denominator to rule out rare adverse events. It lacks the power. Just as with the rotavirus vaccine, only after hundreds of thousands of doses of vaccines are distributed, will such rare events appear often enough to permit detection. For that reason, we must depend upon the modern post-licensure surveillance programs that we already have in place.

Vaccine safety: risk communication--a global perspective

The complexity of risks connected with both vaccine-preventable diseases as well as with immunization will be discussed and used as the basis for conclusions: -what should be done to avoid damage to current and future immunization programs and -how to improve risk communication. The need for more complete data on true, perceived and unknown immunization risks necessitates strengthening our research capabilities as well as surveillance and vaccine safety programs, and to critically examine the factors influencing public sentiments, taking into account that public perceptions of risk vary depending on the characteristics of risk. A concerted effort is needed to improve benefit and risk communication at all levels. The medical community should play a key role for improved communication.

Challenges and controversies in immunization safety

No vaccine is perfectly safe or effective. As diseases such as diphtheria and polio fade, vaccine safety concerns, especially alleged links between vaccinations and several chronic illnesses, have become increasingly prominent in the media and to the public. This article reviews the current scientific evidence on several recent vaccine safety controversies. It also provides information on how various safety research is conducted, some of the concurrent challenges, and finally, some guidance on communicating with patients on vaccine risks.

Recurrent skin peeling following Kawasaki disease

Long term follow up of 259 cases of Kawasaki disease led to the observation that 11% of children have episodes of recurrent peeling of the skin for several years after their recovery. These events were usually associated with an upper respiratory tract infection and were distinct from a recurrence of Kawasaki disease. Repeeling was significantly less frequent in children who had suffered coronary artery dilatation and was more frequently seen in those with nasal staphylococcal colonisation. The mechanism for this phenomenon is unclear, but it has been observed in a number of other conditions caused by infectious agents and their toxins. Paediatricians need to be aware of this phenomenon which is distinct from recurrence of Kawasaki disease.

[Pathology of Haemophilus infections: current situation in pediatrics]

Haemophilus influenzae is the main pathogen in community-acquired infections in children. Prior to the introduction of H. influenzae type b immunization (Hib), capsular type b H. influenzae was the most invasive type of H. influenzae, and was the major cause of meningitis in children in France and many developing countries. The introduction of a Hib vaccine program results in rapid and dramatic decline in the incidence of Hib infections in children. The resistance rate to beta-lactam antibiotics is slowly increasing with beta-lactamase production. Third generation cephalosporins are used for the treatment of invasive infection (meningitis etc.). The empiric treatment of otitis and respiratory tract infections in children is the combination of clavulanic acid and amoxicillin or third generation cephalosporins.

Immunologic hazards associated with vaccination of humans

Universal vaccination remains the most effective measure for preventing the spread of many infectious diseases. Since vaccination is one of the few medical interventions applied to healthy individuals, its safety must be as absolute as human efforts can make it. Questions have been raised recently about the possibility that particular vaccines can trigger or promote autoimmune disease, although controlled, population-based studies have not supported this notion. In collaboration with the World Health Organization, we investigated a subunit vaccine of human chorionic gonadotropin, and found evidence of benign, but not pathologic, autoimmunity. We propose an algorithm for systematic study of possible immunologic hazards of vaccines in animals and human subjects.

Stimulation of the developing immune system can prevent autoimmunity

Both genetic and environmental factors contribute to the development of autoimmunity. Animals and humans exposed to natural infections have a reduced rate of autoimmune diseases. There is increasing evidence that immune stimulation prevents autoimmune diseases. Our hypothesis is that the process of the development of pathogenic cells involved in autoimmunity can be modulated by early stimulation of the immune system in autoimmunity prone individuals This allows for the upregulation of cytokines and growth factors that influence the generation of regulatory cells involved in autoimmunity. As we live in a 'cleaner environment' the decreasing chances of natural infection in the general population may contribute to the induction of autoimmunity because the developing immune system is not exposed to stimulation that may be necessary to generate regulatory cells involved in the modulation and prevention of autoimmunity. Immunization with certain vaccines may provide an alternative approach to stimulate the immune system to modulate or prevent the generation of pathogenic cells involved in autoimmunity by induction of regulatory cells.

Vaccination and autoimmunity-'vaccinosis': a dangerous liaison?

The question of a connection between vaccination and autoimmune illness (or phenomena) is surrounded by controversy. A heated debate is going on regarding the causality between vaccines, such as measles and anti-hepatitis B virus (HBV), and multiple sclerosis (MS). Brain antibodies as well as clinical symptoms have been found in patients vaccinated against those diseases. Other autoimmune illnesses have been associated with vaccinations. Tetanus toxoid, influenza vaccines, polio vaccine, and others, have been related to phenomena ranging from autoantibodies production to full-blown illness (such as rheumatoid arthritis (RA)). Conflicting data exists regarding also the connection between autism and vaccination with measles vaccine. So far only one controlled study of an experimental animal model has been published, in which the possible causal relation between vaccines and autoimmune findings has been examined: in healthy puppies immunized with a variety of commonly given vaccines, a variety of autoantibodies have been documented but no frank autoimmune illness was recorded. The findings could also represent a polyclonal activation (adjuvant reaction). The mechanism (or mechanisms) of autoimmune reactions following immunization has not yet been elucidated. One of the possibilities is molecular mimicry; when a structural similarity exists between some viral antigen (or other component of the vaccine) and a self-antigen. This similarity may be the trigger to the autoimmune reaction. Other possible mechanisms are discussed. Even though the data regarding the relation between vaccination and autoimmune disease is conflicting, it seems that some autoimmune phenomena are clearly related to immunization (e.g. Guillain-Barre syndrome). The issue of the risk of vaccination remains a philosophical one, since to date the advantages of this policy have not been refuted, while the risk for autoimmune disease has not been irrevocably proved. We discuss the pros and cons of this issue (although the temporal relationship (i.e. always 2-3 months following immunization) is impressive).

Immunisation of patients with systemic lupus erythematosus: the current state of play

Concerns regarding the safety and efficacy of immunisation in patients with SLE have persisted for over 50 y and indeed infection remains a leading cause of morbidity and mortality in these patients. There have been many anecdotal reports in the literature linking vaccination with either induction or exacerbation of SLE disease. However prospective studies have shown that immunisation with inactivated/killed vaccines is probably safe in patients with SLE. Individuals on immunosuppressive agents and/or high dose steroid (more than 20 mg/d) should not receive live vaccines, as stated in guidelines proposed by the British Society of Rheumatology. The safety of hepatitis B vaccination in patients with SLE is as yet undetermined and a prospective study is required. However until such evidence becomes available the advice of the BSR should be followed and patients with SLE who are at risk of exposure should be vaccinated. It remains uncertain whether the immune response to immunisation is significantly impaired by active disease and/or immunosuppressive treatment and to what extent. Most patients do however seem to mount a satisfactory immune response though this may not be quantitatively and qualitatively the same as healthy controls.