The risk of vaccination--the importance of "negative" studies

Determinants of parents' reticence toward vaccination in urban areas in Benin (West Africa)

BACKGROUND

Despite the efforts of health authorities, vaccination coverage of targeted child populations is still poor in many regions. Parents' reticence has been identified as one cause of this situation. However, there is little data to explain the phenomenon that could support decision-making.

OBJECTIVE

The objective of the study was to uncover the determinants of this reticence toward vaccination among the religious population of the cities of Parakou and Cotonou in Benin.

METHODS

This was an exploratory study using a qualitative survey of 12 pastors and 30 faithful from churches that are vaccination-reticent and a control group of the same number of faithful belonging to other churches, all Christian. Individual and group interviews were carried out in the local language using a pre-established and pre-tested guide. The data collected underwent discourse content analysis focused on specific themes.

RESULTS

Analysis of the data reveals an erroneous perception of child vaccination. Those who are reticent say vaccination goes against the will of God, that it is a poison from the "white witch doctor", and that those who vaccinate their children are committing a sin. Members of the control group argued against this, but without conviction. They adhere to the principle of obedience to authority, a biblical precept invoked when the vaccinators oblige them to vaccinate their children. Other factors were identified that could explain the reticence, such as the tactlessness of the vaccinators, parents' previous experiences and false rumours about vaccination.

CONCLUSION

The reasons for reticence are mainly related to parents' beliefs in religious principles that are sometimes poorly understood. To limit the spread of this phenomenon, more detailed information and negotiation between the health authorities and the pastors of these churches are essential. ABSTRACT IN FRENCH: See the full article online for a translation of this abstract in French.

Lack of association of Kawasaki disease after immunization in a cohort of infants followed for multiple autoimmune diagnoses in a large, phase-4 observational database safety study of 7-valent pneumococcal conjugate vaccine: lack of association between Kawasaki disease and seven-valent pneumococcal conjugate vaccine

A large-scale, postmarketing observational database safety study was conducted following 7-valent pneumococcal conjugate vaccine (PCV7) licensure. A secondary outcome was the occurrence of predefined diagnoses among PCV7 vaccinees versus historic controls. Forty-two PCV7 recipients and 17 controls were hospitalized for Kawasaki disease (P = 0.012). After adjusting for potential confounding variables, this difference was not significant (P = 0.083). No association between Kawasaki disease and PCV7 was found.

Media coverage of the measles-mumps-rubella vaccine and autism controversy and its relationship to MMR immunization rates in the United States

OBJECTIVE

The purpose of this work was to assess the association between media coverage of the MMR-autism controversy and MMR immunization in the United States.

METHODS

The public-use files of the National Immunization Survey were used to estimate annual MMR coverage from 1995 to 2004. The primary outcome was selective measles-mumps-rubella nonreceipt, that is, those children who received all childhood immunizations except MMR. Media coverage was measured by using LexisNexis, a comprehensive database of national and local news media. Factors associated with MMR nonreceipt were identified by using a logistic regression model.

RESULTS

Selective MMR nonreceipt, occurring in as few as 0.77% of children in the 1995 cohort, rose to 2.1% in the 2000 National Immunization Survey. Children included in the 2000 National Immunization Survey were born when the putative link between MMR and autism surfaced in the medical literature but before any significant media attention occurred. Selective nonreceipt was more prevalent in private practices and unrelated to family characteristics. MMR nonreceipt returned to baseline before sustained media coverage of the MMR-autism story began.

CONCLUSIONS

There was a significant increase in selective MMR nonreceipt that was temporally associated with the publication of the original scientific literature, suggesting a link between MMR and autism, which preceded media coverage of the MMR-autism controversy. This finding suggests a limited influence of mainstream media on MMR immunization in the United States.

Safety and efficacy of meningococcal c vaccination in juvenile idiopathic arthritis

OBJECTIVE

To determine whether vaccinations aggravate the course of autoimmune diseases such as juvenile idiopathic arthritis (JIA) and whether the immune response to vaccinations may be hampered by immunosuppressive therapy for the underlying disease.

METHODS

In this multicenter cohort study, 234 patients with JIA (ages 1-19 years) were vaccinated with meningococcal serogroup C (MenC) conjugate to protect against serogroup C disease (caused by Neisseria meningitidis). Patients were followed up for disease activity for 1 year, from 6 months before until 6 months after vaccination. IgG antibody titers against MenC polysaccharide and the tetanus carrier protein were determined by enzyme-linked immunosorbent assay and toxin binding inhibition assay, respectively. A serum bactericidal assay was performed to determine the function of the anti-MenC antibodies.

RESULTS

No change in values for any of the 6 components of the core set criteria for juvenile arthritis disease activity was seen after MenC vaccination. Moreover, no increase in the frequency of disease relapse was detected. Mean anti-MenC IgG concentrations in JIA patients rose significantly within 6-12 weeks after vaccination. Of 157 patients tested, 153 were able to mount anti-MenC IgG serum levels >2 micro g/ml, including patients receiving highly immunosuppressive medication. The 4 patients with a lower anti-MenC antibody response displayed sufficient bactericidal activity despite receiving highly immunosuppressive medication.

CONCLUSION

The MenC conjugate vaccine does not aggravate JIA disease activity or increase relapse frequency and results in adequate antibody levels, even in patients receiving highly immunosuppressive medication. Therefore, patients with JIA can be vaccinated safely and effectively with the MenC conjugate.

What maintains parental support for vaccination when challenged by anti-vaccination messages? A qualitative study

This study sought to explore how parents respond to competing media messages about vaccine safety. Six focus groups with mothers of infants were shown television vignettes of typical pro- and anti-vaccination claims. Thematic analysis of transcripts was undertaken. Mothers expressed surprise and concern about alleged vaccine risks but quickly reinstated their support for vaccination by deference to authority figures; type-casting immunisation opponents; and notions of anticipatory regret, good parenting and social responsibility. We conclude that personal experiences, value systems and level of trust in health professionals are fundamental to parental decision making about vaccination. Vaccination advocacy should increase the focus on matters of process such as maintaining trust and public confidence, particularly in health professionals. Stories about people affected by vaccine-preventable diseases need to re-enter the public discourse.

Vaccine risk/benefit communication: effect of an educational package for public health nurses

The purpose of this study was to determine whether an in-service for public health nurses (PHNs) and accompanying educational materials could improve vaccine risk/benefit communication. The content and timing of vaccine communication were recorded during 246 pre-and 217 postintervention visits in two public health immunization clinics. Pre-/postintervention comparisons showed PHN communication of severe side effects (13% vs. 44%, p < .0001) and their management (29% vs. 60%, p < .0001) increased. There was no significant change in discussion of vaccine benefits (48% vs. 51%) or common side effects (91% vs. 92%),screening for contraindications (71% vs. 77%), or distribution of written information (89% vs. 92%). More parents initiated vaccine questions postintervention (27% vs. 39%,p < .01) and were more satisfied with vaccine-risk communication (8.1 vs. 8.9 on a 10-point scale, p < .01). Average vaccine communication time increased from 16 to 22 seconds (p < .01).

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.

No epidemiological evidence for infant vaccinations to cause allergic disease

CONTEXT

The prevalence of allergic diseases has increased considerably over the last decades. The hygiene hypothesis has emerged, linking reduced microbial exposure and infections early in life with the development of allergic diseases. Especially some of currently available non-replicating infant vaccines are unlikely to mimic a natural infection-mediated immune response that protects against the development of allergic diseases. Moreover, several studies suggested infant vaccinations to increase the risk of allergic diseases.

OBJECTIVE

To determine whether infant vaccinations increase the risk of developing allergic disease.

DATA SOURCES

We searched MEDLINE from 1966 to March 2003 and bibliography lists from retrieved articles, and consulted experts in the field to identify all articles relating vaccination to allergy.

STUDY SELECTION AND DATA EXTRACTION

We selected epidemiological studies with original data on the correlation between vaccination with diphtheria, pertussis, tetanus (DPT), measles, mumps, rubella (MMR) and Bacillus Calmette-Guérin (BCG) vaccine in infancy and the development of allergic diseases, and assessed their quality and validity.

DATA SYNTHESIS

Methodological design and quality varied considerably between the studies we reviewed. Many studies did not address possible confounders, such as the presence of lifestyle factors, leaving them prone to bias. The studies that offer the stronger evidence, including the only randomized controlled trial at issue published to date, indicate that the infant vaccinations we investigated do not increase the risk of developing allergic disease. Furthermore, BCG does not seem to reduce the risk of allergies.

CONCLUSIONS

The reviewed epidemiological evidence indicates that, although possibly not contributing to optimal stimulation of the immune system in infancy, current infant vaccines do not cause allergic diseases.

Pertussis vaccination and the risk of respiratory syncytial virus-associated hospitalization

BACKGROUND

Animal data suggest an association between recent vaccination with a pertussis-containing vaccine and increased severity of respiratory syncytial virus (RSV) infection. We sought to determine whether such an association exists in humans by studying a population-based cohort of young children.

PATIENTS AND METHODS

We performed a nested case-control study of 280 children younger than 24 months of age hospitalized with RSV infection in Olmsted County, MN from January 1990 to December 1999. Controls (2 per case) consisted of nonhospitalized residents of Olmsted County matched to cases by date of birth and sex. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for the odds of hospitalization for RSV infection among subjects with a recent pertussis-containing vaccination in proximity to the cases' date of hospitalization relative to the odds among subjects with no vaccination.

RESULTS

The OR for receipt of a pertussis-containing vaccine within 0 to 6 days of a case's hospitalization for RSV disease was 0.8 (95% CI 0.4-1.8). For the time intervals 7-13, 14-20 and > or =21 days, the OR were 1.3 (95% CI 0.5-3.0), 1.3 (95% CI 0.5-3.2) and 0.7 (95% CI 0.3-1.5), respectively. Adjusting for vaccine delay and for risk status did not alter the findings. The median interval between the most recent pertussis-containing vaccine and the case's date of hospitalization was 40 days for cases and 42.5 days for controls (P = 0.69). Among the RSV cases, pertussis vaccination in the month preceding hospitalization was not a risk factor for oxygen requirement (P = 0.82), intensive care unit admission (P = 0.46) or need for mechanical ventilation (P = 0.28).

CONCLUSION

In our study, recent immunization with a pertussis-containing vaccine was not a risk factor for hospitalization for RSV infection. In addition, among children hospitalized with RSV infection, recent pertussis immunization was not associated with a more severe clinical course.

Ethics and vaccination

BACKGROUND

Immunization programmes are ethically defensible and society has a significant role to play in providing vaccination against measles and safeguarding herd immunity to optimize its individuals' capabilities. Since preventive actions interfere with individuals who consider themselves as healthy, public health strategies - as distinct from advice in a clinical consultation - require something approaching certainty as to benefits and possible side effects of an intervention. The principle of individual autonomy, a fundamental value in bioethics, often makes discussions covering ethical issues in public health interventions difficult and non-productive as to practical solutions. In encounters intended to provide information on vaccination, discussions regarding risks tend to simplify the issue into an individual one: either the child gets measles or not, or is affected by side effects or not.

METHOD AND CONCLUSIONS

A model is suggested for identification and analysis of the ethical conflicts in measles vaccination programmes, which contains two different dimensions: the affected persons and the relevant ethical principles. Justice as solidarity, not utility, should be paired with autonomy in ethical deliberations on preventive health interventions such as a vaccination programme for measles. If the goal is solidarity rather than conformity, the parents must be free to decide what they think is right, because that is what moral responsibility is all about. Solidarity, however, could never be accepted as an argument without parents trusting the messages from the health institutions and availability of reasonable societal support for those who claim an association between vaccinations and possible side effects.

The effects of occupational exposure to chlorpyrifos on the neurologic examination of central nervous system function: a prospective cohort study

Questions persist about adverse effects such as impaired cognition and attention, incoordination, spasticity, or parkinsonism from chronic, low-level exposures to organophosphate (OP) compounds. In a prospective cohort study, we evaluated chlorpyrifos-manufacturing workers and a referent group on 2 occasions, 1 year apart, to determine whether occupational exposure to chlorpyrifos produced clinically evident central nervous system (CNS) dysfunction. Chlorpyrifos subjects had significantly higher TCP excretion and lower average BuChE activity than referents in a range in which physiological effects on B-esterases exist. Few subjects had neurologic symptoms or signs, and there were no significant group differences in terms of signs at baseline or second examinations. Chronic chlorpyrifos exposure produced no clinical evidence of cortical, pyramidal tract, extrapyramidal, or other CNS dysfunction among chlorpyrifos subjects compared with referents, either at baseline or after 1 year of additional chlorpyrifos exposure.

Childhood Vaccine Risk/Benefit Communication Among Public Health Clinics: A Time-Motion Study

United States law requires that immunization providers use Centers for Disease Control Vaccine Information Statements (VISs) and inform parents about vaccine risks and benefits prior to every childhood immunization. A recent national survey found that public health clinics (PHCs) reported high compliance with this law. To further investigate these findings, we conducted an immunization time-motion study in two PHCs in Kansas and Louisiana. Research assistants observed a convenience sample of 246 child immunization visits to record distribution of the VISs and content and time of vaccine communication. Thirty percent of parents read below a ninth grade level, 53% had Medicaid insurance, and 56% were Black. VISs were given with every dose of vaccine administered in 89% of visits. Public health nurses (PHNs) frequently discussed potential vaccine side effects (91%), treatment of side effects (91%), and the vaccine schedule (93%). Contraindications were screened in 71% of visits. Benefits were discussed in 48% of visits and severe risks in 29%. The national Vaccine Injury Compensation Program (VICP) was never discussed. The immunization visits lasted for a mean of 20 min. Vaccine communication of side effects, risks, benefits, screening for contraindications, and the next visit lasted for an average of 16 s for all vaccines. PHC compliance with mandated VIS distribution and practical vaccine communication was high. Room for improvement exists in discussion of benefits, serious risks, and the VICP.

Effect of infant immunisation with meningococcus serogroup C-CRM(197) conjugate vaccine on diphtheria immunity and reactogenicity in pre-school aged children

The majority of Men C conjugate vaccines given in the UK use CRM(197), a mutant diphtheria toxoid, as their protein carrier. We studied the effects of prior immunisation with Men C-CRM(197) conjugate vaccine on immunity to diphtheria in 193 children before and after a booster dose of Men C at 4 years. Baseline diphtheria antibodies were higher in children given four previous doses of Men C (P<0.0001) and tended to be higher following boosting in those who had received three or four doses. This enhanced immunity was not associated with increased reactogenicity.

Adverse reactions to vaccines

(The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.) Immunization healthcare is becoming increasingly complex as the number and types of vaccines have continued to expand. Like all prescription drugs, vaccines may be associated with adverse events. The majority of these reactions are self-limited and not associated with prolonged disability. The media, Internet and public advocacy groups have focused on potentially serious vaccine-associated adverse events with questions raised about causal linkages to increasing frequencies of diseases such as autism and asthma. Despite a lack of evidence of a causal relationship to a variety of vaccine safety concerns, including extensive reviews by the Institute of Medicine, questions regarding vaccine safety continue to threaten the success of immunization programs. Risk communication arid individual risk assessment is further challenged by the public health success of vaccine programs creating the perception that certain vaccines are no longer necessary or justified because of the rare reaction risk. There is a need for improved understanding of true vaccine contraindications and precautions as well as host factors and disease threat in order to develop a patient specific balanced risk communication intervention. When they occur, vaccine related adverse events must be treated, documented and reported through the VAERS system. The increasing complexity of vaccination health care has led the Center of Disease Control and Prevention (CDC) to identify Vaccine Safety Assessment and Evaluation as a potential new specialty.

The overall safety profile of currently available vaccines directed against infectious diseases

The vaccines currently used worldwide for the prevention of infectious diseases are quite safe in comparison to most pharmaceutical and biological agents. Vaccine components may contribute to inflammatory, allergic or anaphylactic reactions. Most adverse events are transient and well-tolerated. Transient severe adverse reactions occur at rates of one in one thousand vaccinations; permanent severe adverse reactions occur on the order of one in one million. The most common of the severe adverse reactions are syncope and allergic reactions. Providers can take steps to prevent or ameliorate these reactions by pursuing both prelicensure testing (albeit limited) and postlicensure testing and monitoring. Systems that enhance the detection of safety concerns include national passive and active surveillance as well as regional vaccine registries and provider-based patient education. Since vaccines are used in universal programmes, their safety is paramount to their continued acceptance. Healthcare managers, including administrators of hospitals, clinics, practice groups, health maintenance organisations (HMOs) and managed care plans, can and should support providers in minimising adverse events associated with vaccines by supporting postvaccination observation policies, postlicensure testing and surveillance, vaccine registries and patient education systems.

Cost-effectiveness of hepatitis A vaccination in children, adolescents, and adults

Hepatitis A is a major public health problem in the United States and other developed countries, largely because decreased natural immunity allows for increased susceptibility. To evaluate the cost-effectiveness of routine vaccination of children, adolescents, and certain high-risk adults against hepatitis A, economic analyses of hepatitis A vaccination were identified through searches of MEDLINE, EMBASE, and BIOSIS (February, 1992, to December, 2001) for studies, reviews, editorials, and letters from peer-reviewed journals published in English, French, German, Italian, or Spanish. Experts were also contacted. Articles conforming to accepted standards of quality for health-economic studies were used to compile data on vaccination of children, and results were synthesized in a narrative review. This review of economic analyses of vaccine use in several developed countries shows cost-effectiveness comparable with that of other vaccines in children and within accepted boundaries for adolescents and high-risk adults.

No short-term immunological effects of Pneumococcus vaccination in patients with systemic lupus erythematosus

OBJECTIVE

to investigate the early immunological effects of Pneumococcus vaccination in SLE patients and healthy controls.

METHODS

First-four-week follow-up of 18 patients and 9 healthy controls by repeated measurements of anti-nuclear antibodies, anti-dsDNA, C-reactive protein, complement factor 3 (C3) and 4 (C4), total IgG, IgA and IgM. Specific antibody response, percentage of blood lymphocyte populations and whole blood chemiluminescence measurements were carried out in six patients and six controls.

RESULTS

No disease flare was detected in the vaccinated patients. all side effects were mild. The concentrations of serum IgG, IgA, C3 and C4 decreased significantly, but still remained within the normal range. The other changes were statistically non-significant. The specific antibody responses to 6B and 23F Pneumococcus serotypes showed striking individual differences.

CONCLUSION

There was no short-term immunological effect of Pneumococcus vaccination in the patients with SLE. The non-responders. without any sign of disease activation should possibly be given more immunogenic, new vaccines to avoid life-threatening Pneumococcus infections.

The challenge of vaccine safety

Vaccines always will involve some risk, and risk always involves some public concern. Although the benefits of routine vaccination greatly outweigh any adverse effects, our consumer society seeks to eliminate all risk. The balance of risk and benefit appears to falter by the very success of preventing disease: in the immediate absence of the disease, the resolve to vaccinate waivers. We cannot expect the public to think in terms of the decision analyst and carefully weigh probability, risk, and benefit in a numerical fashion. In fact, the public's approach toward vaccination is varied and unscientific. Recognizing these challenges, we propose a program of continued vigilance by increasing our scientific base and methodology, improving vaccine safety communication through research and resources, maintaining a tolerance of conscientious objection as a safety valve for mandated routine vaccination in civilians, and calling for more research funding for the development of new vaccines.

Measles vaccination and inflammatory bowel disease: controversy laid to rest?

The increasing incidence of Crohn's disease has lead to speculation about changes in exposures to environmental or infectious agents. Considerable attention has focused on the role of measles infection and/or vaccination in the pathogenesis of Crohn's disease and ulcerative colitis. Current evidence regarding the association between measles vaccination and inflammatory bowel disease (IBD) comprises analytic epidemiological studies, a case-series report and ecological studies. The first of these, a 1995 cohort study, found an association between measles vaccination and Crohn's disease and ulcerative colitis, but was widely questioned on methodological grounds. This was followed by a 1997 case-control study showing no association between measles vaccination and IBD. In 1998, public concern was rekindled by a report of 12 children with nonspecific colitis, ileal-lymphoid-nodular hyperplasia, and developmental disorders largely attributed to measles-mumps-rubella vaccine, but the nature of the report limited its scientific conclusions. Two additional studies, one case-control and one cohort, then followed and neither found an association with measles vaccination. Of the several ecological studies of measles vaccine coverage or measles schedule changes, none found an association with rates of IBD. The role of measles infection in IBD has been examined more extensively with studies of in utero measles exposure, measles infection early in life, and laboratory based investigations. An initial report of high rates of Crohn's disease among pregnancies affected by measles infection was followed by negative studies. Numerous case-control and ecological studies of children with measles infections early in life have also had discordant findings. Of three recent cohort studies, two showed no relationship between infection with early measles exposure and risk for IBD, while one found an approximate 3-fold elevation in risk. Laboratory investigations into persistent measles infection and IBD have been contentious. While some investigators have claimed to find persistent measles infection among patients with IBD, others, using highly sensitive polymerase chain reaction techniques, have not been able to replicate the findings. Recent controversy has centred on whether there is any evidence for molecular mimicry in the pathogenesis of IBD. In summary, available evidence does not support an association between measles-containing vaccines and risk of IBD, nor between measles infection and IBD. While further research is necessary into the causal factors underlying Crohn's disease and ulcerative colitis, continued public education efforts are needed to reassure the public about vaccine safety and to prevent declines in vaccine coverage.

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.

Drug-induced vasculitis

DIV is a relatively common cause of inflammatory vasculitis. Drugs from almost every pharmacologic class have been implicated in causing vasculitis in sporadic cases. The level of certainty and quality of evidence for these associations between specific agents and vasculitis vary greatly. The clinical manifestations of DIV range from single organ involvement (most commonly, skin) to life-threatening multiorgan disease. The recently described subset of cases of DIV associated with positive tests for ANCA are an interesting subset of DIV. The diagnosis of DIV is usually one of exclusion. The treatment of DIV is dependent on the severity of disease activity but should always include withdrawal of the suspected drug. If no agent can be implicated, as many drugs as feasible should be discontinued. The necessity of prescribing glucocorticoids or immunosuppressive agents depends on the disease severity and other case-specific information. Increasing understanding of the pathophysiologic characteristics of all inflammatory vasculitides should lead to better diagnostic and therapeutic approaches to DIV.