No epidemiological evidence for infant vaccinations to cause allergic disease

Modulation of Skin Inflammatory Responses by Aluminum Adjuvant

Aluminum salt (AS), one of the most commonly used vaccine adjuvants, has immuno-modulatory activity, but how the administration of AS alone may impact the activation of the skin immune system under inflammatory conditions has not been investigated. Here, we studied the therapeutic effect of AS injection on two distinct skin inflammatory mouse models: an imiquimod (IMQ)-induced psoriasis-like model and an MC903 (calcipotriol)-induced atopic dermatitis-like model. We found that injection of a high dose of AS not only suppressed the IMQ-mediated development of T-helper 1 (Th1) and T-helper 17 (Th17) immune responses but also inhibited the IMQ-mediated recruitment and/or activation of neutrophils and macrophages. In contrast, AS injection enhanced MC903-mediated development of the T-helper 2 (Th2) immune response and neutrophil recruitment. Using an in vitro approach, we found that AS treatment inhibited Th1 but promoted Th2 polarization of primary lymphocytes, and inhibited activation of peritoneal macrophages but not bone marrow derived neutrophils. Together, our results suggest that the injection of a high dose of AS may inhibit Th1 and Th17 immune response-driven skin inflammation but promote type 2 immune response-driven skin inflammation. These results may provide a better understanding of how vaccination with an aluminum adjuvant alters the skin immune response to external insults.

A multidisciplinary effort to increase COVID-19 vaccination among the older adults

Background

COVID-19 vaccination significantly reduces the risk of infection and its associated morbidity and mortality. However, poor uptake of the COVID-19 vaccination was reported among the high-risk group of older people amidst emerging variants of concern. This community case study reports an outreach program in Singapore, COVE (COVID-19 Vaccination for the Elderly) initiated by healthcare workers in a cluster of primary care clinics. They assessed the vaccine hesitancy among these older persons, addressed their concerns and facilitated their vaccination appointment during a brief phone conversation.

Method

Twenty one thousand six hundred and sixty three unvaccinated adults aged ≥60 years were contacted by healthcare worker volunteers over two phases from June to October 2021. In phase I, they contacted adults aged above 70 years over 2 weeks. Adults who were uncontactable in phase I and those aged 60–69 years were sent SMS in phase II. Data were analyzed via descriptive data analysis.

Results

After phase 1, 65.5% (n = 5,646/8,617) of older adults had received at least one dose of the COVID-19 vaccine. The respondents expressed intention to vaccinate (39%, n = 3,390), requested to seek further information (25%, n = 2,138), reported access barrier (8%, n = 715), or were concerned of the vaccine adverse effects (3%, n = 288). Vaccination was refused by 24% (n = 2,086) of the respondents. Eventually 60.4% (n = 13,082/21,663) of them were vaccinated 3 months after COVE implementation.

Conclusion

The COVE program increased the COVID-19 vaccination uptake of older adults from 84.6 to 96.3%. A person-centric proactive approach by healthcare workers addressed vaccine hesitancy and optimized vaccination. The outreach scheduling of vaccination appointments is key in promoting vaccination uptake among older adults.

Atopic diseases and airway-related symptoms in Bavarian pre-schoolers: determinants and association with immunization

BACKGROUND

Atopic diseases are among the most common chronic conditions in childhood. Causes of allergies are manifold. The aim of this paper is to evaluate risk factors for atopic diseases and unremitting wheeze and to examine if there is an association between measles, mumps and rubella (MMR) vaccination and atopic dermatitis, asthma and unremitting wheeze in Bavarian pre-schoolers.

METHODS

Parents filled out a questionnaire on children's health and environmental and socioeconomic factors. The questionnaire was administered within the Health Monitoring Units in a cross-sectional study in Bavaria, Germany (2014/2015). Data on vaccinations were obtained via the School Entrance Examination, a mandatory examination for pre-school children in Bavaria. Rates of influential factors of atopic diseases and wheeze, MMR and DTP (diphtheria, pertussis and tetanus) vaccination were calculated for all children stratified by health outcomes. To examine if there is an association between MMR vaccination and health outcomes, a multiple logistic regression analysis was performed.

RESULTS

Data were available for 3237 individuals. Symptoms and diseases were more frequent in boys. Higher parental education was associated with a higher prevalence of atopic dermatitis. There were no significant associations between any of the health outcome groups and MMR vaccination in the multiple logistic regression models with adjustment for potential confounders.

CONCLUSIONS

The present study is in line with the current state of research that MMR vaccination is not associated with atopic diseases.

Vaccine Hesitancy: Drivers and How the Allergy Community Can Help

Vaccine hesitancy-defined by the World Health Organization (WHO) as a "delay in acceptance or refusal of vaccines despite availability of vaccination services"-is not a recent phenomenon. Historical records indicate that vaccine hesitancy existed by the 18th century in Europe and even resulted in violent riots. The drivers of vaccine hesitancy have evolved over the last 200 years but not, perhaps, as much as one might expect. More problematic are the means by which concerns over vaccine hesitancy are communicated by a new landscape of digital communication, generating what has been described as an "infodemic" in which an overabundance of information-both factual and misinformation-contributes to hesitancy. In this review, we discuss the background and current drivers of vaccine hesitancy and the evidence base for strategies to combat this. We highlight the important role the allergy/immunology community could have in working to mitigate vaccine hesitancy, particularly with respect to the current coronavirus disease 2019 (COVID-19) pandemic.

[Prevention of canine parvovirosis - Part 3: Vaccine-associated adverse events]

Although nowadays vaccines, especially those against canine parvovirus (CPV), are considered to be safe, vaccine-associated adverse events (VAAEs) can occur in rare cases. Some VAAEs are mild and manifest shortly (within a few days) after vaccination (e. g. gastrointestinal signs, fever, reduced general condition, lymphadenopathy). These signs are likely a result of vaccine virus replication and indicate a good immune response. Anaphylactic reactions can also occur promptly following vaccine administration and might be life threatening. Affected dogs show clinical signs such as edema, salivation, vomiting, diarrhea, hypotension, and/or shock. Since it is often unclear which component of the vaccine carries responsibility for the anaphylactic reaction it is important to limit future vaccinations of these dogs to indispensable components only. When revaccination is unavoidable, e. g. because antibodies against CPV cannot be detected, combined vaccines should not be used and CPV (and other components, if needed) should preferably be vaccinated separately. Changing the vaccine manufacturer might also prevent further anaphylactic reactions. Finally, there are VAAEs occurring after a prolonged period of time. In dogs, it is discussed that autoimmune diseases, such as immune-mediated hemolytic anemia (IMHA), can be a consequence of excessive vaccination or in the least be triggered by vaccination. Numerous dogs with IMHA are reported to have a history of receiving a vaccination within a few weeks before the onset of clinical sings. In such dogs, further vaccinations should generally be avoided.

Childhood vaccination and allergy: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

As the rise in prevalence of allergic diseases worldwide corresponds in time with increasing infant vaccination, it has been hypothesized that childhood vaccination may increase the risk of allergic disease. We aimed to synthesize the literature on the association between childhood vaccination and allergy.

DESIGN

We searched the electronic databases PubMed and EMBASE (January 1946-January 2018) using vaccination and allergy terms.

METHODS

Two authors selected papers according to the inclusion criteria. Pooled effects across studies were estimated using random-effects meta-analysis. Due to inadequate number of homogeneous publications on newer and underused vaccines, meta-analysis was limited to allergic outcomes following administration of (Bacillus Calmette-Guérin) BCG, measles or pertussis vaccination. The review was prospectively registered in the PROSPERO systematic review registry (NO: CRD42017071009).

RESULTS

A total of 35 publications based on cohort studies and 7 publications based on randomized controlled trials (RCTs) met the inclusion criteria. RCTs: From 2 studies, early vaccination with BCG vaccine was associated with a reduced risk of eczema (RR = 0.83; 95% CI = 0.73-0.93; I²  = 0%) but not food allergy or asthma. No association was found between pertussis vaccine and any allergic outcome based on a single RCT.

COHORT STUDIES

Childhood measles vaccination was associated with a reduced risk of eczema (RR = 0.65; 95% CI = 0.47-0.90, I²  = 0.0%), asthma (RR = 0.78; 95% CI = 0.62-0.98, I²  = 93.9%) and, with a similar, statistically non-significant reduction in sensitization (RR = 0.78; 95% CI = 0.61-1.01, I²  = 19.4%).

CONCLUSIONS

We found no evidence that childhood vaccination with commonly administered vaccines was associated with increased risk of later allergic disease. Our results from pooled analysis of both RCTs and cohort studies suggest that vaccination with BCG and measles vaccines were associated with a reduced risk of eczema.

Vaccines do not cause atopic dermatitis: A systematic review and meta-analysis

BACKGROUND

Previous studies found conflicting results about the association of vaccinations and likelihood of atopic dermatitis (AD).

OBJECTIVES

To determine whether vaccinations increase the likelihood of AD.

METHODS

A systematic review was performed of all published studies in MEDLINE, EMBASE, LILACS, Scopus, and Web of Science databases. At least 2 reviewers conducted title/abstract, full-text review, and data extraction. Quality of evidence was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

Forty-four studies met inclusion criteria; 37 had sufficient data for meta-analysis. There were no associations any vaccine regimen (random-effects logistic regression: odds ratio [95% confidence interval]: 0.961 [0.822-1.124]; n = 21 studies) BCG (0.927 [0.701-1.226]; n = 8), pertussis (0.790 [0.416-1.499]; n = 4), single (1.031 [0.920-1.155]; n = 17) or multiple vaccines (0.902 [0.608-1.338]; n = 7) with likelihood of AD. This remained true in studies with high-quality (NOS ≥ 7) (OR [95% CI]: 0.941 [0.793-1.117]; n = 13 studies) or low-quality (NOS < 7) (OR [95% CI]: 1.058 [0.669-1.674]; n = 8 studies).

LIMITATIONS

No randomized controlled trials.

CONCLUSIONS

No vaccine regimen was consistently associated with developing AD.

Fact vs Fallacy: The Anti-Vaccine Discussion Reloaded

In the light of the COVID-19 pandemic, anti-vaccine sentiments have been on the rise, with a recent seminal study on the development of anti-vaccine views in social media even making its way into Nature Communications. Yet, with the current scientific consensus being in overwhelming agreement over the safety and efficacy of vaccines, many scientists lose their grasp on the fears, concerns, and arguments that the opposition may hold. This paper discusses and evaluates vaccine-hesitant individuals on a socioeconomic, historical, and philosophical landscape. It also provides an analysis of common argumentative patterns and the psychological impact that these arguments may have on undecided individuals. The discussion also explores why anti-vaccine sentiments are on the rise, and how members of the scientific and medical community require a more structured approach to communicating key arguments. This is particularly important if vaccination rates and herd immunity are to be sustained. No longer is it sufficient to win arguments based on a factual and scientific basis, but rather scientists and medical practitioners have to focus on conveying confidence and reassurance on both an informative and emotional level to those with doubts and fears.

Vaccination and Allergic Sensitization in Early Childhood - The ALADDIN Birth Cohort

BACKGROUND

The increasing incidence of allergic diseases highlights the importance of finding underlying mechanisms. Early vaccination has been suggested as one influential factor. However, it is difficult to find a study group with a large variation between subjects concerning compliance to the official vaccination program. The anthroposophic lifestyle is of interest in this context. Moreover, cohort studies show that children of families with this lifestyle run a lower risk of allergic sensitization and allergy-related disease.

METHODS

From the prospective birth cohort ALADDIN we included one group from the anthroposophic community, with restrictive attitudes concerning vaccinations, and two other groups of age-matched children with more conventional parental lifestyles. In all, 466 children were followed from birth to five years of age. Detailed vaccination data and blood samples were collected at six months, one, two, and five years. Information was also obtained on risk factors for allergy. The outcome variable, allergic sensitization was defined as allergen-specific serum IgE levels ≥ 0.35 kU_A/L.

FINDINGS

In a logistic regression model adjusted for socio-demographics and established allergy risk factors, vaccination at later age or having a lower number of injections or vaccines were associated with low OR for allergic sensitization during the first year of life. However, after adjustment for anthroposophic lifestyle, no statistically significant associations remained. The adjusted OR for sensitization at five years of age in children not receiving any vaccinations (n = 54) was 0.98 [95% CI 0.38-2.57].

INTERPRETATION

We found no support for an association between early childhood vaccination and subsequent allergic sensitization. Our findings do not support scepticism towards early childhood vaccination motivated by allergy risk.

Safety of Quadrivalent Meningococcal Conjugate Vaccine in Children 2-10 Years

BACKGROUND

Quadrivalent meningococcal conjugate vaccine is recommended for children, adolescents and adults at increased risk of meningococcal disease. In 2011, MenACWY-CRM (Menveo, GSK, Siena, Italy) was approved for children 2-10 years of age in the United States. Although no safety concerns arose from clinical trials, it remains important to monitor its safety in routine clinical settings.

METHODS

Kaiser Permanente Southern California members 2-10 years old who received MenACWY-CRM between September 2011 and September 2014 were included. Electronic health records were searched using a validated algorithm to identify 26 prespecified events of interests (EOIs) and serious medically attended events (SMAEs) from inpatient or emergency settings up to 1 year after MenACWY-CRM vaccination. SMAEs were categorized by International Classification of Diseases, 9th revision diagnostic categories. All events were reviewed to confirm the diagnosis and symptom onset date. The study was descriptive (NCT01452438); no statistical tests were performed.

RESULTS

Among 387 vaccinated children, 327 with ≥6 months membership before vaccination were analyzed. Among EOIs, 9 asthma cases and 1 myasthenia gravis case underwent chart review which confirmed 1 incident asthma case occurring 237 days after concomitant vaccination with MenACWY-CRM and typhoid vaccine. Thirty-one children experienced SMAEs, most commonly because of unrelated injury and poisoning. The remaining events occurred sporadically after vaccination and most were unlikely related to vaccination based on medical record review.

CONCLUSIONS

One incident EOI of asthma late in the 1-year observation period and sporadic distribution of SMAEs were observed. These data do not suggest safety concerns associated with MenACWY-CRM vaccination in children 2-10 years old.

Vaccination and allergy: EAACI position paper, practical aspects

Immunization is highly effective in preventing infectious diseases and therefore an indispensable public health measure. Allergic patients deserve access to the same publicly recommended immunizations as non-allergic patients unless risks associated with vaccination outweigh the gains. Whereas the number of reported possible allergic reactions to vaccines is high, confirmed vaccine-triggered allergic reactions are rare. Anaphylaxis following vaccination is rare, affecting <1/100 000, but can occur in any patient. Some patient groups, notably those with a previous allergic reaction to a vaccine or its components, are at heightened risk of allergic reaction and require special precautions. Allergic reactions, however, may occur in patients without known risk factors and cannot be predicted by currently available tools. Unwarranted fear and uncertainty can result in incomplete vaccination coverage for children and adults with or without allergy. In addition to concerns about an allergic reaction to the vaccine itself, there is fear that routine childhood immunization may promote the development of allergic sensitization and disease. Thus, although there is no evidence that routine childhood immunization increases the risk of allergy development, such risks need to be discussed.

Pertussis immunization in infancy and adolescent asthma medication

BACKGROUND AND OBJECTIVES

Childhood immunization may influence the development of asthma, possibly due to lack of infections or a shift in the T-helper cell type 1/T-helper cell type 2/regulatory T cells balance. We therefore investigated whether pertussis immunization in infancy is associated with asthma medication in adolescence.

METHODS

After 14 years of no general pertussis vaccination, almost 82,000 Swedish children were immunized for pertussis in a vaccination trial between June 1, 1993, and June 30, 1994. In a follow-up analysis of almost 80,000 children, their data were compared with those of ∼100,000 nonvaccinated children, born during a 5-month period before and a 7-month period after the vaccination trial. Data for the main outcome variable (ie, dispensed prescribed asthma medication for each individual in the cohort during 2008-2010) were obtained from the national prescription database. Multivariate regression models were used to calculate the effect size of vaccination on dispensed asthma medication (odds ratios [OR], 95% confidence intervals [CI]). Approaches similar to intention-to-treat and per-protocol methods were used.

RESULTS

The prevalence rates of various asthma medications for study patients at 15 years of age differed between 4.6% and 7.0%. The crude ORs for any asthma medication and antiinflammatory treatment in pertussis-vaccinated children after intention-to-treat analysis were 0.97 (95% CI: 0.93-1.00) and 0.94 (95% CI: 0.90-0.98), respectively. Corresponding adjusted ORs were 0.99 (95% CI: 0.95-1.03) and 0.97 (95% CI: 0.92-1.01). Similar ORs were found after per-protocol analysis.

CONCLUSIONS

Pertussis immunization in infancy does not increase the risk of asthma medication use in adolescents. Our study presents evidence that pertussis immunization in early childhood can be considered safe with respect to long-term development of asthma.

How aluminum adjuvants could promote and enhance non-target IgE synthesis in a genetically-vulnerable sub-population

Aluminum-containing adjuvants increase the effectiveness of vaccination, but their ability to augment immune responsiveness also carries the risk of eliciting non-target responses, especially in genetically susceptible individuals. This study reviews the relevant actions of aluminum adjuvants and sources of genetic risk that can combine to adversely affect a vulnerable sub-population. Aluminum adjuvants promote oxidative stress and increase inflammasome activity, leading to the release of IL-1β, IL-18, and IL-33, but not the important regulatory cytokine IL-12. In addition, they stimulate macrophages to produce PGE₂, which also has a role in regulating immune responses. This aluminum-induced cytokine context leads to a T(H)2 immune response, characterized by the further release of IL-3, IL-4, IL-5, IL-9, IL-13, and IgE-potentiating factors such as sCD23. Genetic variants in cytokine genes, such as IL-4, IL-13, IL-33, and IL-18 influence the response to vaccines in children and are also associated with atopy. These genetic factors may therefore define a genetically-vulnerable sub-population, children with a family history of atopy, who may experience an exaggerated T(H)2 immune response to aluminum-containing vaccines. IL-4, sCD23, and IgE are common factors for both atopy and the immune-stimulating properties of aluminum adjuvants. IL-4 is critical in the production of IgE and total IgE up-regulation. IL-4 has also been reported to induce the production of sCD23 and trigger resting sIgM+, sIgD+ B-cells to switch to sIgE+ B-cells, making them targets for IgE-potentiating factors. Further, the actions of IgE-potentiating factors on sIgE+ B-cells are polyclonal and unrestricted, triggering their differentiation into IgE-forming plasma cells. These actions provide a mechanism for aluminum-adjuvant promotion and enhancement of non-target IgE in a genetically vulnerable sub-population. Identification of these individuals may decrease the risk of adverse events associated with the use of aluminum-containing vaccines.

Diverse microbial exposure - consequences for vaccine development

Numerous epidemiological studies suggest that there is an inverse relationship between "immunologically mediated diseases of affluence", such as allergy, diabetes and inflammatory bowel disease on one hand and few infections encountered in early childhood, on the other hand. Careful analysis of the epidemiological, clinical and animal studies taken together, however, suggests that the protection is mediated by broad exposure to a wealth of commensal, non-pathogenic microorganisms early in life, rather than by infections. Microbial exposure has little relationship with "hygiene" in the usual meaning of the word and the term "hygiene hypothesis" is therefore misleading. A better term would be "microbial deprivation hypothesis". The suggestion that childhood infections would protect against allergic disease led to unfortunate speculations that vaccinations would increase the risk for allergies and diabetes. Numerous epidemiological studies have therefore been conducted, searching for a possible relationship between various childhood vaccinations on one hand and allergy on the other hand. It is reasonable from these studies to conclude that vaccinations against infectious agents neither significantly increase, nor reduce the likelihood of immunologically mediated diseases. It is established that the postnatal maturation of immune regulation is largely driven by exposure to microbes. Germ free animals manifest excessive immune responses when immunised and they do not develop normal immune regulatory function. The gut is by far the largest source of microbial exposure, as the human gut microbiome contains up to 1014 bacteria, i.e. ten times the number of cells in the human body. Several studies in recent years have shown differences in the composition of the gut microbiota between allergic and non-allergic individuals and between infants living in countries with a low and a high prevalence of immune mediated diseases. The administration of probiotic bacteria to pregnant mothers and postnatal to their infants has immune modulatory effects. So far, however, probiotic bacteria do not seem to significantly enhance immune responses to vaccines. The potential to improve vaccine responses by modifying the gut microbiota in infants and the possibility to employ probiotic bacteria as adjuvants and/or delivery vehicles, is currently explored in several laboratories. Although to date few clinical results have been reported, experimental studies have shown some encouraging results.

Asthma prevalence and exacerbations in children: is there an association with childhood vaccination?

Infections and vaccinations may have a potential role in the normal maturation of the immune system, in the development and balance of regulatory pathways, and in the development and exacerbations of asthma. Asthma exacerbations often result from respiratory viral infections, and, while vaccination towards common viral infections may reduce the occurrence of such exacerbations, there has been concern that vaccinations can increase the risk of asthma. Current studies show that childhood vaccines, including inactivated influenza vaccine, are generally safe. However, there is some concern regarding possible exacerbations in infants or children with frequent wheezing or persistent asthma who are given live-attenuated influenza vaccination. Although severe allergic adverse events attributable to vaccination are extremely rare, all serious allergic reactions should be further assessed to detect the likely causative vaccine component, such as egg protein or gelatin. The risks of not vaccinating children far outweigh the risks of allergy and asthma exacerbations. Therefore, childhood vaccination should remain an essential part of child health programs and should not be withheld, even from children with asthma or those predisposed to allergy.

Prevalence and factors linked to allergic rhinitis in 10 and 11-year-old children in Almería. Isaac Phase II, Spain

BACKGROUND

Allergic rhinitis affects 10-30% of children in developed countries and has increased in frequency over the last few decades, probably due to changes in the environment and life style.

AIM

To assess the prevalence, severity, and factors linked to rhinitis in 10 and 11-year-old children from Almeria (Spain).

METHODS

As part of ISAAC II, a cross-sectional survey was conducted among a representative sample of 1143 schoolchildren in spring and autumn of 2001, using homologated questionnaires and skin-prick testing.

RESULTS

The overall prevalence of rhinitis and rhinoconjunctivitis were 38.9% and 24.8%, respectively, 17.9% had medically diagnosed rhinitis. During the previous year symptoms disturbed daily activities and school attendance in some measure in 40% and 26% of children with rhinitis, respectively. The risk factors found in the multiple logistic regression analysis were atopy (OR 2.57; 95% CI 1.92-3.42); cat contact at home during first year of life (OR 2.4 95% CI 1.13-5.12); prior medical diagnosis of asthma (OR 2.2; 95% CI 1.22-4.02); nocturnal cough in absence of colds (OR 1.9; 95% CI 1.25-2.97); diagnosis of rhinitis in one of the parents (OR 1.8; 95% CI 1.31-2.59); wheezing at any time (OR 1.6; 95% CI 1.18-2.28); and nursery school attendance (OR 1.5; 95% CI 1.21-2.5).

CONCLUSIONS

The prevalence of rhinitis found is superior to that of other centres participating in the ISAAC Phases I and II, and coexists with asthma and eczema in many children. The independent risk factors associated to rhinitis are in accordance with previous reports.

Update on vaccination guidelines for allergic children

Children with allergic or atopic diseases require immunization just like non-atopic children. However, vaccination of such children requires some special considerations and precautions. Children may be allergic to specific vaccine constituents such as gelatin or egg. Children who have suffered an apparent allergic reaction to a vaccine should be evaluated by an allergist to determine the culprit allergen and to make recommendations regarding future vaccination. In rare circumstances, certain vaccines may cause acute exacerbations of allergic diseases, but the contention that vaccination causes allergic disease is not substantiated by any available evidence.

Measles-mumps-rubella vaccination and asthma-like disease in early childhood

The authors evaluated the association between receipt of measles-mumps-rubella (MMR) vaccine and asthma-like disease in early childhood in a Danish nationwide cohort study (N = 871,234). Two outcomes were included: hospitalizations with asthma diagnoses and use of anti-asthma medications (for a subset of the cohort only). Poisson regression was used to estimate rate ratios according to vaccination status. MMR-vaccinated children were less often hospitalized with an asthma diagnosis (rate ratio (RR) = 0.75, 95% confidence interval (CI): 0.73, 0.78) and used fewer courses of anti-asthma medication (RR = 0.92, 95% CI: 0.91, 0.92) than unvaccinated children. This "protective" effect of MMR vaccine was more pronounced for hospitalizations with severe asthma diagnoses (status asthmaticus: RR = 0.63, 95% CI: 0.49, 0.82) and use of medication that was highly specific for asthma (long-acting beta2-agonist inhalant: RR = 0.68, 95% CI: 0.63, 0.73). MMR vaccine was not negatively associated with anti-asthma medications often used for wheezing illnesses in early childhood (systemic beta2-agonist: RR = 1.02, 95% CI: 1.01, 1.02). These results are compatible not with an increased risk of asthma following MMR vaccination but rather with the hypothesis that MMR vaccination is associated with a reduced risk of asthma-like disease in young children.

Measles, mumps and rubella infections and atopic disorders in MMR-unvaccinated and MMR-vaccinated children

Vaccinations have been incriminated in the increase of atopic disorders. Especially the measles-mumps-rubella (MMR) vaccination is often refused by people having a notion that these infectious diseases are beneficial for a healthy development of a child's immune system. This practice endangers herd immunity and is the cause of repeated outbreaks. As the clinical course of infections and also its possible impact on the development of atopy may be different in vaccinated and unvaccinated individuals, we explored in vaccinated and unvaccinated children associations of MMR infection with atopic disorders. Using data from a previously conducted study on the relationship between the diphtheria-tetanus-pertussis-(inactivated) poliomyelitis vaccination in the first year of life and atopic disorders, the study population of 1872 8-12-yr-old was divided as children MMR-unvaccinated and children MMR-vaccinated in the first year of life. Within each group the association between MMR infections and atopic disorders (both as reported by the parents) was assessed. We found a statistically significant positive association between measles infection and 'any atopic disorder' [adjusted odds ratio, OR (95% confidence interval, CI): 1.77 (1.20-2.61)] in the MMR-vaccinated group, mainly because of the relationship with eczema. For rubella there was a negative association with eczema and food allergy in the unvaccinated group: adjusted OR (95% CI): 0.57 (0.38-0.85) and 0.23 (0.07-0.76), respectively. All other associations were not statistically significant. We found a positive relationship between measles infection and any atopy in a group of MMR-vaccinated children and a negative association between rubella infection and eczema and food allergy in unvaccinated children. However, we cannot conclude that these relationships are causal. The negative association with rubella may be an artefact. This study shows no evidence for any protective effects from MMR diseases for the development of atopy and therefore supports conclusions found elsewhere that childhood vaccinations do not cause atopy.

The public perception of the value of vaccines - the case of Switzerland

Aim

In this original article, we seek to analyse the environment in which immunisation policies are adopted and, more specifically, the way the public perception of vaccines influences decision-making, by looking more closely at the case of Switzerland.

Subjects and methods

Historical and present-day examples of attitudes towards immunisation and specific vaccines, both on the part of the public and of health-care workers, are reviewed.

Results

Decision-making with regard to vaccine policy implementation has been and is still most often driven by fear: fear of disease (when perceived as rampant and/or dangerous), but also fear of vaccine-associated adverse events (when the disease is less or no longer “visible”). However, methodology for introducing evidence-based immunisation policies exists and can be used by public health authorities, while vaccination information systems (such as the Swiss InfoVac) have proven their usefulness in providing trustworthy, peer-based knowledge to health-care workers.

Conclusion

Only information based on clear, evidence-based data gathered and analysed according to solid methodological criteria coupled with adequate information of health-care workers (and thus patients) can ensure in future the implementation of scientifically coherent, publicly acceptable, and equitable immunisation policies.

Prevalence and associated factors of allergic rhinitis and atopic dermatitis in children

Allergic disorders are the chronic diseases of greatest pediatric morbidity, affecting over 25 % of the pediatric population. Indeed, this situation has been referred to as an "allergic epidemic". In comparison with asthma, atopic dermatitis and allergic rhinitis have been less extensively investigated, although this does not mean that they should be regarded as minor disorders but rather as alterations that affect the quality of life of the patients and their families, which generate considerable direct and indirect costs. Despite an important research effort, the reason for this allergic epidemic is not well known. These are multifactor disorders without a single causal agent, in which the most important component is the genetic predisposition of the patient (atopy), modulated by environmental factors, exposure to allergens, infections and irritants, among others. A confounding element is the fact that the concept of allergic diseases encompasses phenotypes of rhinitis, atopic dermatitis or asthma in which no IgE-mediated atopic mechanism is demonstrated, and which can manifest in a way similar to true allergic phenotypes. Differentiation between the two is difficult to establish on the basis of self-administered questionnaires alone, in the absence of a precise etiological diagnosis. The present article reviews the numerous factors suggested to be responsible for the increase in allergic diseases recorded in the last few decades, and for the differences in prevalence observed among centres. For most of these factors the results published in the literature are contradictory, in some cases due to a lack of control of the associated interacting or confounding factors. Consensus exists for only some of these causal factors, such as the established parallelism between the increase in allergic diseases and the reduction in infectious processes on one hand, and the increase in particles generated by diesel fuel combustion on the other. In addition, the implicated factors could act differently (and in some cases even antagonically) upon atopy and on the different disease phenotypes, thereby complicating the study of these interactions even further.

Reported pertussis infection and risk of atopy in 8- to 12-yr-old vaccinated and non-vaccinated children

Pertussis infection has been suspected to be a potential causal factor in the development of atopic disease because of the effect of pertussis immunization on specific IgE antibodies. Although several studies found a positive association between pertussis infection and atopic disorders, this relationship has not yet been studied in a population stratified by vaccination status. To assess the association between pertussis infection and atopic disorders in pertussis-unvaccinated children and in pertussis-vaccinated children. Using data from a previously conducted study on the relationship between the diphtheria-tetanus-pertussis-(inactivated) poliomyelitis vaccination in the first year of life and atopic disorders, the study population of 1872 8-12 yr old was divided into children pertussis-unvaccinated and children pertussis-vaccinated in the first year of life. Within each group, the association between pertussis infection and atopic disorders (both as reported by the parents) was assessed. In the unvaccinated group, there were no significant associations between pertussis infection and atopic disorders. In the vaccinated group, all associations between pertussis infection and atopic disorders were positive, the associations with asthma [odds ratio (OR) = 2.24, 95% confidence interval (CI(95%)): 1.36-3.70], hay fever (OR = 2.35, CI(95%): 1.46-3.77) and food allergy (OR = 2.68, CI(95%): 1.48-4.85) being significant. There was a positive association between pertussis infection and atopic disorders in the pertussis vaccinated group only. From the present study, it cannot be concluded whether this association is causal or due to reverse causation.

Genetic variation in the response to vaccination

Vaccines are the most powerful means to prevent and diminish the burden of infectious disease. However, there are limitations to their use: vaccines are not yet available for all infectious diseases (including human immunodeficiency virus and respiratory syncytial virus), they sometimes lack efficacy, the response to vaccination is limited by maternal antibodies in very young infants, and the response to vaccination is variable or may even be absent in some individuals. This review focuses on genetic factors that determine the variable response to vaccination. The highly polymorphic human leukocyte antigen system, which is involved in antigen presentation, has been researched most in this aspect, and clearly affects the response to vaccination. Other, but less polymorphic pathways involved are the Toll-like receptor pathway, which is involved in antigen recognition and stimulation of the immune system, and the cytokine immunoregulatory network. The heritability, or the proportion of total variance that is due to additive genetic factors, appears to be particularly large for vaccine-induced antibody responses in young infants compared with cell-mediated responses and antibody responses in older, immunologically more mature individuals. Both antibody and cell-mediated responses are not only affected by loci within, but also strongly by loci outside the human leukocyte antigen system. Because most genes that are important in influencing immune responses to vaccination are still unknown, clearly more work is required. A better understanding of the factors that determine an effective response to vaccination may lead to the identification of specific genes and pathways as targets for the development of novel more uniformly effective vaccines.

Is childhood vaccination associated with asthma? A meta-analysis of observational studies

BACKGROUND

The possible link between immunization and atopic diseases has been under intense debate in the last decade.

OBJECTIVE

The aim of this study was to systematically review the available evidence on the association of whole-cell pertussis and BCG vaccination with the risk of asthma in childhood and adolescence.

METHODS

The major medical electronic databases (Medline, National Library of Medicine Gateway, and Cochrane Library) were searched, and reference lists of the relevant publications were reviewed for relevant birth-cohort studies and randomized, controlled trials from 1966 to March 2006. Only studies that directly compared vaccinated and unvaccinated children, validated vaccination status by medical charts, and used preset criteria to define asthma were included. Data were abstracted by using a standardized protocol and computerized report form. Results were analyzed by applying a fixed-effect or random-effect model, according to the heterogeneity of the studies. Sensitivity analyses by scoring criteria were performed.

RESULTS

Seven studies of pertussis vaccination (with a total of 186,663 patients) and 5 studies of BCG vaccination (with a total of 41,479 patients) met our inclusion criteria. No statistically significant association was detected between either whole-cell pertussis or BCG vaccination and incidence rates of asthma during childhood and adolescence. This lack of a significant association proved to be robust on sensitivity analyses for BCG but not for pertussis vaccine.

CONCLUSIONS

Currently available data, based on observational studies, do not support an association, provocative or protective, between receipt of the BCG or whole-cell pertussis vaccine and risk of asthma in childhood and adolescence.

The complex link between immunization against childhood diseases and allergy

Vaccines can be at the origin of allergic manifestations in susceptible children. Such manifestations include: immediate-type hypersensitivity (anaphylactic shock, rash or angioedema) within 1 h after the injection; semi-late hypersensitivity (local inflammatory lesion such as the Arthus phenomenon) a few hours after the injection; and delayed-type hypersensitivity (abscess or eczema at the site of the injection). Furthermore, early-life vaccinations have been implicated in the modulation of the immune system as they could promote the development of allergy by avoiding infections. However, most population-based studies have not found an increased risk of allergies in vaccinated children. Due to methodological problems in conducting the studies, further investigations are needed to better understand the phenomenon.

Diphtheria, pertussis, poliomyelitis, tetanus, and Haemophilus influenzae type b vaccinations and risk of eczema and recurrent wheeze in the first year of life: the KOALA Birth Cohort Study

OBJECTIVES

Among potential etiologic factors for atopic manifestations, infant vaccinations have recently been discussed. We evaluated in a prospective design whether infants who were unvaccinated or vaccinated according to incomplete vaccination schedules in the first 6 months of age were at decreased risk for eczema and recurrent wheeze in the first year of life.

METHODS

Information on vaccinations against diphtheria, pertussis, poliomyelitis, tetanus; Haemophilus influenzae type b vaccine; and eczema and recurrent wheeze was collected by repeated questionnaires in 2764 families participating in the KOALA Birth Cohort Study in The Netherlands. A standard vaccination schedule referred to 3 diphtheria, pertussis, poliomyelitis, tetanus, and Haemophilus influenzae type b vaccinations in the first 6 months with the first given in months 1 to 3; an incomplete vaccination schedule was defined as any other vaccination schedule. Exclusion criteria were prematurity (gestational age <37 weeks) and congenital abnormalities related to immunity (such as Down syndrome). Multiple logistic regression models were fitted to adjust for confounding factors.

RESULTS

During the first year of life, the incidence of eczema was 23% (584 of 2537 infants) and of recurrent wheeze, the incidence was 8.5% (203 of 2402 infants). At age 6 months, 1969 (77%) of 2545 infants had been vaccinated according to a standard schedule, 393 (15%) vaccinated according to an incomplete schedule, and 182 (7%) never vaccinated. Compared with infants with standard vaccination schedules, infants with incomplete schedules did not differ significantly in eczema risk or recurrent wheeze. This was also true for infants who had never been vaccinated.

CONCLUSION

This study shows that the risk of eczema or recurrent wheeze at 1 year of age does not differ between infants with different vaccination status at the age of 6 months.

Do vaccines modify the prevalence of asthma and allergies?

Epidemiological studies suggest the hypothesis that the increase in asthma and allergies in the industrialized world can be explained by a decline in the number of infectious diseases occurring during childhood. In the context of this 'hygiene hypothesis', is immunization in early life a risk factor for promoting allergic diseases? The majority of studies, especially those conducted with more extensive populations, have not found an increased risk, and although 'not finding an increased risk' is not the same as 'the non-existence of any risk at all', it seems that the evidence is tipped in favor of the absence of risk. Conversely, although some surveys have described a protective effect of vaccination, the majority refuted this result. If there is any effect, it is probably a weak one.

Vaccinating behaviour, information, and the dynamics of SIR vaccine preventable diseases

The increasing level of disease control by vaccination jointly with the growing standard of living and health of modern societies could favour the spread of exemption as a "rational" behaviour towards vaccination. Rational exemption implies that families will tend to relate the decision to vaccinate their children to the available information on the state of the disease. Using an SIR model with information dependent vaccination we show that rational exemption might make elimination of the disease an unfeasible task even if coverages as high as 100% are actually reached during epochs of high social alarm. Moreover, we show that rational exemption may also become responsible for the onset of sustained oscillations when the decision to vaccinate also depends on the past history of the disease.

Effects of a diphtheria-tetanus-acellular pertussis vaccine on immune responses in murine local lymph node and lung allergy models

We have previously shown that in mice, diphtheria-tetanus-acellular pertussis (DTaP) vaccination before Bordetella pertussis infection resulted in, besides effective clearance, immediate hypersensitivity (lung eosinophilia, increased total serum immunoglobulin E [IgE], and increased ex vivo Th2 cytokine production by cells from the bronchial lymph nodes). To better appreciate the extent of these findings, we measured DTaP vaccination effects in the local lymph node assay (LLNA) and an ovalbumin (OVA) lung allergy model. In the LLNA, mice were vaccinated or adjuvant treated before being sensitized with trimellitic anhydride (TMA; inducing a Th2-directed response) and dinitrochlorobenzene (DNCB; inducing a Th1-directed response). Compared to the adjuvant-treated controls, the vaccinated mice showed a decreased response to TMA and (to a much lesser extent) an increased response to DNCB. The decreased response to TMA coincided with increased transforming growth factor beta levels. With the exception of filamentous hemagglutinin, all vaccine constituents contributed to the decreased response to TMA. In the lung allergy model, sensitization induced OVA-specific IgE, lung pathology (peribronchiolitis, perivasculitis, and hypertrophy of the bronchiolar mucus cells) and increased the number of eosinophils, lymphocytes, and neutrophils in the bronchoalveolar lavage fluid. Vaccination failed to modulate these parameters. In conclusion, although DTaP vaccination may affect the LLNA response, we found no evidence of an effect on lung allergy.

Ecological association between childhood asthma and availability of indoor chlorinated swimming pools in Europe

BACKGROUND

It has been hypothesised that the rise in childhood asthma in the developed world could result at least in part from the increasing exposure of children to toxic chlorination products in the air of indoor swimming pools.

OBJECTIVES

Ecological study to evaluate whether this hypothesis can explain the geographical variation in the prevalence of asthma and other atopic diseases in Europe.

METHODS

The relationships between the prevalences of wheezing by written or video questionnaire, of ever asthma, hay fever, rhinitis, and atopic eczema as reported by the International Study of Asthma and Allergies in Childhood (ISAAC), and the number of indoor chlorinated swimming pools per inhabitant in the studied centres were examined. Associations with geoclimatic variables, the gross domestic product (GDP) per capita, and several other lifestyle indicators were also evaluated.

RESULTS

Among children aged 13-14 years, the prevalence of wheezing by written questionnaire, of wheezing by video questionnaire, and of ever asthma across Europe increased respectively by 3.39% (95% CI 1.96 to 4.81), 0.96% (95% CI 0.28 to 1.64), and 2.73% (95% CI 1.94 to 3.52), with an increase of one indoor chlorinated pool per 100 000 inhabitants. Similar increases were found when analysing separately centres in Western or Northern Europe and for ever asthma in Southern Europe. In children aged 6-7 years (33 centres), the prevalence of ever asthma also increased with swimming pool availability (1.47%; 95% CI 0.21 to 2.74). These consistent associations were not found with other atopic diseases and were independent of the influence of altitude, climate, and GDP per capita.

CONCLUSIONS

The prevalence of childhood asthma and availability of indoor swimming pools in Europe are linked through associations that are consistent with the hypothesis implicating pool chlorine in the rise of childhood asthma in industrialised countries.

Early life circumstances and atopic disorders in childhood

The prevalence of childhood atopic disorders has risen dramatically in the last decades of the past century. Risk factors for the development of these disorders have been studied extensively. This review focuses on the role of early life risk factors such as pre-natal development, perinatal circumstances, birth order and childhood vaccinations.

Haemophilus influenzae type b vaccination and reported atopic disorders in 8-12-year-old children

Because Haemophilus influenzae type b (Hib) vaccination was added recently to most vaccination programs, no conclusive data on the relationship with atopic disorders are yet available. We sought to assess the risk of atopic disorders at ages 8-12 years associated with Hib vaccination in the first year of life, in addition to diphtheria-tetanus-pertussis-inactivated poliomyelitis vaccination (DTP-IPV) and other childhood vaccinations. Parents of 1,201 children attending Orthodox Reformed (Protestant) primary schools in The Netherlands returned questionnaires reporting data on vaccination status, atopic symptoms and physician-diagnosed lifetime atopic disorders (asthma, hay fever, eczema, and food allergy), and possible confounders. This study was conducted within the framework of a larger study on the relationship between the DTP-IPV and reported atopic disorders. The adjusted odds ratio of any atopic disorder (Hib-vaccinated/unvaccinated) was 1.09 (95% confidence interval (CI), 0.79-1.50). For asthma, hay fever, eczema, and food allergy, the results were, respectively, 0.89 (95% CI, 0.55-1.43), 0.94 (95% CI, 0.47-1.90), 1.09 (95% CI, 0.75-1.58), and 0.68 (95% CI, 0.38-1.19). In conclusion, in the Dutch population, there is no indication for a higher risk of reported physician-diagnosed atopic disorders at primary schools age after Hib vaccination in the first year of life, in addition to other vaccinations.

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.

Diphtheria tetanus pertussis poliomyelitis vaccination and reported atopic disorders in 8-12-year-old children

BACKGROUND

Evidence for the relationship between the diphtheria tetanus pertussis (DTP) vaccination and atopic disorders is inconclusive, because the available studies that constitute the evidence are liable to confounding by indication.

STUDY OBJECTIVE

To assess the relationship between diphtheria-tetanus-pertussis-(inactivated) poliomyelitis vaccination (DTP-IPV) in the first year of life and reported atopic disorders at primary school age.

METHOD

1875 children attending Orthodox Reformed (Protestant) primary schools in the Netherlands returned questionnaires with data on vaccination status, atopic symptoms and lifetime atopic disorders (asthma, hay fever, eczema and food allergy), and possible confounders.

RESULTS

The adjusted odds ratio of any atopic disorder (vaccinated/unvaccinated) was 1.00 (CI95%: 0.80-1.24). For asthma, hay fever, eczema and food allergy the results were respectively: 1.04 (CI95%: 0.76-1.42), 0.79 (CI95%: 0.55-1.12), 0.87 (CI95%: 0.66-1.14) and 1.13 (CI95%: 0.71-1.81).

CONCLUSION

The DTP-IPV vaccination was not related to reported atopic disorders at primary school age.

The hygiene hypothesis revisited

The original hygiene hypothesis proposed that reductions in family size and exposure to childhood infections were responsible for the rise in atopic diseases. Numerous epidemiologic and longitudinal studies have been performed to test this hypothesis, which has evolved in response to these findings and emerging concepts related to the innate immune response and immunoregulatory mechanisms. Collectively, these advances raise hope that the concepts espoused in original hygiene hypothesis may soon lead to new preventive approaches to atopic diseases.

Measles

PURPOSE OF REVIEW

The purpose of this review is to summarize important papers concerning measles disease and measles-containing vaccines published in 2004.

RECENT FINDINGS

Endemic measles has been successfully controlled in the Americas and, to a lesser extent, in Europe. This has been achieved with a high uptake of two doses of a measles-containing vaccine. Even in industrialized countries, where vaccine uptake is poor, for example Japan, the disease is still a significant cause of morbidity and mortality. Vaccine failure is predominantly due to primary vaccine failure, which may, in part, be genetic in origin and related to HLA type. Measles-containing vaccines have been shown to be associated with febrile convulsions, but there is no strong evidence of a link with atopy. There is considerable evidence that there is no causal relationship with autistic disorders. In spite of this, many parents and some professionals have concerns about the safety of the vaccines, which may lead to their underuse.

SUMMARY

It is possible to eliminate measles with a high uptake of two doses of measles-containing vaccine, but concerns about safety persist and need to be tackled. More research is required into how to do this effectively and also to elucidate the causes of vaccine failure.