Vaccines and autism: evidence does not support a causal association

Explaining Health Misinformation Belief through News, Social, and Alternative Health Media Use: The Moderating Roles of Need for Cognition and Faith in Intuition

Explaining the spread and impact of health misinformation has garnered considerable attention with the uptake of social media and group messaging applications. This study contributes to that line of work by investigating how reliance on multiple digital media may help support or suppress misinformation belief, and how individual differences in misinformation susceptibility condition this process. Alternative health outlets (AH media), advocating home/homeopathic remedies over conventional medicine can be important sources of misinformation, yet are largely ignored previously. In this study, we first test how reliance on different platforms predicts health misinformation belief. Drawing from the elaboration likelihood model, we further investigate how need for cognition (NFC) and faith in intuition (FI) moderate the relationship between news reliance and susceptibility to misinformation. We conducted a survey in Singapore, Turkey, and the U.S (N = 3,664) to measure how these proposed relationships explain misinformed beliefs about vaccines, genetically modified foods and alternative medicine. We found reliance on online legacy news was negatively associated with the likelihood of believing health misinformation, while the reverse was true for social media and AH media. Additionally, those with both greater NFC and FI were more susceptible to health misinformation when they relied on social media and AH media more. In contrast, neither NFC nor FI moderated the relationship between reliance on online legacy news and health misinformation belief. These findings, mostly consistent across countries, also show that extensive reliance on social media and AH media for news mostly overwhelms the individual differences in predicting misinformation belief.

A Millian Case for Censoring Vaccine Misinformation

The spread of vaccine misinformation may contribute to vaccine refusal/hesitancy and consequent harms. Nonetheless, censorship is often rejected on the grounds of free expression. This article examines John Stuart Mill's influential defence of free expression but finds that his arguments for freedom apply only to normal, reasonably favourable circumstances. In other cases, it may be permissible to restrict freedom, including freedom of speech. Thus, while Mill would ordinarily defend the right to express false views, such as that vaccines cause autism, he might have accepted restrictions on anti-vaccine misinformation during the present pandemic. This illustrates that even the staunchest defenders of free speech can permit temporary restrictions in exceptional circumstances.

Knowledge and attitude on infant vaccination among university staff in Malaysian public university

OBJECTIVE

To determine the knowledge and attitude on infant vaccination among a couple of Universiti Putra Malaysia (UPM) staffs in Serdang, Selangor.

METHODS

A cross-sectional study was carried out involving 97 respondents. A cluster sampling technique for the categorization of the faculty in UPM to science-based and non-science-based is used. Then, fishbowl technique was adopted in selecting the faculty from the two categorizations, which consists of 1) science-based: Faculty Biotechnology and Science Biomolecule and Faculty of Science; 2) non-science-based: Faculty of Economics and Management and Faculty of Language and Communication. Consequently, a simple random method was used to choose the respondent based on the inclusion and exclusion criteria. Data on socio-demographic characteristic, knowledge and attitude regarding infant vaccination were collected using a modified and pretested questionnaire. The data then were analyzed using SPSS version 22.

RESULTS

Of 97 respondents, 78 (80.4%) had high knowledge, and 49 (50.5%) have moderate attitude regarding infant vaccination. Overall, science-based faculty and non-science-based faculty prevalence of refuse infant vaccination was 2.1%, 6.5%, respectively. There was a significant association between educational level and the knowledge (p < .05, p = .019). However, there was no significant association between socio-demographic and attitude. Other than that,, there was no association between knowledge and attitude among these two different types of faculty (P > .05, p = .256, p = .597).

CONCLUSION

Effort are needed for focusing on health education campaign with collaboration between health-care professionals, social media and community to improve their awareness for immunization.

How to counter the anti-vaccine rhetoric: Filling information voids and building resilience

Widely circulating anti-vaccine misinformation online has been constituting a large obstacle for the success of COVID-19 vaccination campaigns and for the well-being of people during the pandemic. In this paper we discuss strategies to mitigate negative effects of online anti-vaccine contents on public health and to prevent hesitant individuals from falling prey of the traps set by anti-vaccine disinformation spreaders. Here we discuss the importance of filling information voids and understanding trends and concerns that shape the vaccine debate, and we highlight the relevance of building resilience to vaccine misinformation by strengthening public health and digital literacy.

Vaccine Efficacy Denial: A Growing Concern Affecting Modern Science, and Impacting Public Health

BACKGROUND

The discovery of the vaccination technique has been revealed by Edward Jenner in 1796: undoubtedly, it represents the first scientific attempt to control an infectious disease by vaccines, followed by other important studies carried out by Pasteur and Koch, and Sabin, who developed the first technique to attenuate the virus. In recent decades, numerous scholars have begun to create dangerous theories against the effectiveness of vaccines through scientifically invalid or fraudulent studies.

AIM

This critical review of the literature aims to analyse the main factors that have undermined the credibility of vaccines in the general population, to disprove false information and, on the other hand, emphasize the benefits of vaccines over the last 200 years.

DISCUSSIONS

Unfortunately, several studies have been carried out without the proper scientific rigour. The most impacting example is the study published by Andrew Wakefield in the Lancet journal that tried to correlate vaccines with the development of autism: this publication was withdrawn from the journal a few years after its publication, but the impact of incorrect scientific studies, fake news, and ambiguous healthcare policies has led to an adverse general opinion about the effectiveness of vaccines.

CONCLUSION

The excess of uncontrolled information is a serious concerning in the Coronavirus pandemic. The modern science must tackle this problem with a better willingness to communicate even the clinical studies to those people not able to understand the medical information autonomously. Nevertheless, a reliable science must also limit the dissemination of studies that do not meet the basic criteria of a methodological rigor and certainty of results, in order not to feed confusion in the scientific community.

Capsid destabilization and epitope alterations of human papillomavirus 18 in the presence of thimerosal

Thimerosal has been widely used as a preservative in drug and vaccine products for decades. Due to the strong propensity to modify thiols in proteins, conformational changes could occur due to covalent bond formation between ethylmercury (a degradant of thimerosal) and thiols. Such a conformational change could lead to partial or even complete loss of desirable protein function. This study aims to investigate the effects of thimerosal on the capsid stability and antigenicity of recombinant human papillomavirus (HPV) 18 virus-like particles (VLPs). Dramatic destabilization of the recombinant viral capsid upon thimerosal treatment was observed. Such a negative effect on the thermal stability of VLPs preserved with thimerosal was shown to be dependent on the thimerosal concentration. Two highly neutralizing antibodies, 13H12 and 3C3, were found to be the most sensitive to thimerosal treatment. The kinetics of antigenicity loss, when monitored with 13H12 or 3C3 as probes, yielded two distinctly different sets of kinetic parameters, while the data from both monoclonal antibodies (mAbs) followed a biphasic exponential decay model. The potential effect of thimerosal on protein function, particularly for thiol-containing proteinaceous active components, needs to be comprehensively characterized during formulation development when a preservative is necessary.

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Altered antigenicity of thimerosal-treated HPV VLPs was observed with antibodies.

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Antigenicity reduction and capsid destabilization were concentration dependent.

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The kinetics of epitope-specific antigenicity loss were monitored in real time.

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The reduced antigenicity of adjuvant-adsorbed antigens was visualized.

Review: Vaccine Myth-Buster - Cleaning Up With Prejudices and Dangerous Misinformation

Although vaccines have already saved and will continue to save millions of lives, they are under attack. Vaccine safety is the main target of criticism. The rapid distribution of false information, or even conspiracy theories on the internet has tremendously favored vaccine hesitancy. The World Health Organization (WHO) named vaccine hesitancy one of the top ten threats to global health in 2019. Parents and patients have several concerns about vaccine safety, of which the ubiquitous anxieties include inactivating agents, adjuvants, preservatives, or new technologies such as genetic vaccines. In general, increasing doubts concerning side effects have been observed, which may lead to an increasing mistrust of scientific results and thus, the scientific method. Hence, this review targets five topics concerning vaccines and reviews current scientific publications in order to summarize the available information refuting conspiracy theories and myths about vaccination. The topics have been selected based on the author's personal perception of the most frequently occurring safety controversies: the inactivation agent formaldehyde, the adjuvant aluminum, the preservative mercury, the mistakenly-drawn correlation between vaccines and autism and genetic vaccines. The scientific literature shows that vaccine safety is constantly studied. Furthermore, the literature does not support the allegations that vaccines may cause a serious threat to general human life. The author suggests that more researchers explaining their research ideas, methods and results publicly could strengthen the general confidence in science. In general, vaccines present one of the safest and most cost-effective medications and none of the targeted topics raised serious health concerns.

The anti-vaccination infodemic on social media: A behavioral analysis

Vaccinations are without doubt one of the greatest achievements of modern medicine, and there is hope that they can constitute a solution to halt the ongoing COVID-19 pandemic. However, the anti-vaccination movement is currently on the rise, spreading online misinformation about vaccine safety and causing a worrying reduction in vaccination rates worldwide. In this historical time, it is imperative to understand the reasons of vaccine hesitancy, and to find effective strategies to dismantle the rhetoric of anti-vaccination supporters. For this reason, we analyzed the behavior of anti-vaccination supporters on the platform Twitter. Here we identify that anti-vaccination supporters, in comparison with pro-vaccination supporters, share conspiracy theories and make use of emotional language. We demonstrate that anti-vaccination supporters are more engaged in discussions on Twitter and share their contents from a pull of strong influencers. We show that the movement's success relies on a strong sense of community, based on the contents produced by a small fraction of profiles, with the community at large serving as a sounding board for anti-vaccination discourse to circulate online. Our data demonstrate that Donald Trump, before his profile was suspended, was the main driver of vaccine misinformation on Twitter. Based on these results, we welcome policies that aim at halting the circulation of false information about vaccines by targeting the anti-vaccination community on Twitter. Based on our data, we also propose solutions to improve the communication strategy of health organizations and build a community of engaged influencers that support the dissemination of scientific insights, including issues related to vaccines and their safety.

The role of conspiracy mentality in denial of science and susceptibility to viral deception about science

Members of the public can disagree with scientists in at least two ways: people can reject well-established scientific theories and they can believe fabricated, deceptive claims about science to be true. Scholars examining the reasons for these disagreements find that some individuals are more likely than others to diverge from scientists because of individual factors such as their science literacy, political ideology, and religiosity. This study builds on this literature by examining the role of conspiracy mentality in these two phenomena. Participants were recruited from a national online panel (N = 513) and in person from the first annual Flat Earth International Conference (N = 21). We found that conspiracy mentality and science literacy both play important roles in believing viral and deceptive claims about science, but evidence for the importance of conspiracy mentality in the rejection of science is much more mixed.

Polarization of the vaccination debate on Facebook

BACKGROUND

Vaccine hesitancy has been recognized as a major global health threat. Having access to any type of information in social media has been suggested as a potential influence on the growth of anti-vaccination groups. Recent studies w.r.t. other topics than vaccination show that access to a wide amount of content through the Internet without intermediaries resolved into major segregation of the users in polarized groups. Users select information adhering to theirs system of beliefs and tend to ignore dissenting information.

OBJECTIVES

The goal was to assess whether users' attitudes are polarized on the topic of vaccination on Facebook and how this polarization develops over time.

METHODS

We perform a thorough quantitative analysis by studying the interaction of 2.6 M users with 298,018 Facebook posts over a time span of seven years and 5 months. We applied community detection algorithms to automatically detect the emergence of communities accounting for the users' activity on the pages. Also, we quantified the cohesiveness of these communities over time.

RESULTS

Our findings show that the consumption of content about vaccines is dominated by the echo chamber effect and that polarization increased over the years. Well-segregated communities emerge from the users' consumption habits i.e., the majority of users consume information in favor or against vaccines, not both.

CONCLUSION

The existence of echo chambers may explain why social-media campaigns that provide accurate information have limited reach and be effective only in sub-groups, even fomenting further opinion polarization. The introduction of dissenting information into a sub-group is disregarded and can produce a backfire effect, thus reinforcing the pre-existing opinions within the sub-group. Public health professionals should try to understand the contents of these echo chambers, for example by getting passively involved in such groups. Only then it will be possible to find effective ways of countering anti-vaccination thinking.

Prenatal mercury exposure and features of autism: a prospective population study

Background

Mercury (Hg) has been suspected of causing autism in the past, especially a suspected link with vaccinations containing thiomersal, but a review of the literature shows that has been largely repudiated. Of more significant burden is the total quantity of Hg in the environment. Here, we have used the Avon Longitudinal Study of Parents and Children (ALSPAC) to test whether prenatal exposure from total maternal blood Hg in the first half of pregnancy is associated with the risk of autism or of extreme levels of autistic traits. This is the largest longitudinal study to date to have tested this hypothesis and the only one to have considered early pregnancy.

Methods

We have used three strategies: (1) direct comparison of 45 pregnancies resulting in children with diagnosed autism from a population of 3840, (2) comparison of high scores on each of the four autistic traits within the population at risk (n~2800), and (3) indirect measures of association of these outcomes with proxies for increased Hg levels such as frequency of fish consumption and exposure to dental amalgam (n > 8000). Logistic regression adjusted for social conditions including maternal age, housing circumstances, maternal education, and parity. Interactions were tested between risks to offspring of fish and non-fish eaters.

Results

There was no suggestion of an adverse effect of total prenatal blood Hg levels on diagnosed autism (AOR 0.89; 95% CI 0.65, 1.22) per SD of Hg (P = 0.485). The only indication of adverse effects concerned a measure of poor social cognition when the mother ate no fish, where the AOR was 1.63 [95% CI 1.02, 2.62] per SD of Hg (P = 0.041), significantly different from the association among the offspring of fish-eaters (AOR = 0.74 [95% CI 0.41, 1.35]).

Conclusion

In conclusion, our study identifies no adverse effect of prenatal total blood Hg on autism or autistic traits provided the mother ate fish. Although these results should be confirmed in other populations, accumulating evidence substantiates the recommendation to eat fish during pregnancy.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0215-7) contains supplementary material, which is available to authorized users.

The putative role of environmental aluminium in the development of chronic neuropathology in adults and children. How strong is the evidence and what could be the mechanisms involved?

The conceptualisation of autistic spectrum disorder and Alzheimer's disease has undergone something of a paradigm shift in recent years and rather than being viewed as single illnesses with a unitary pathogenesis and pathophysiology they are increasingly considered to be heterogeneous syndromes with a complex multifactorial aetiopathogenesis, involving a highly complex and diverse combination of genetic, epigenetic and environmental factors. One such environmental factor implicated as a potential cause in both syndromes is aluminium, as an element or as part of a salt, received, for example, in oral form or as an adjuvant. Such administration has the potential to induce pathology via several routes such as provoking dysfunction and/or activation of glial cells which play an indispensable role in the regulation of central nervous system homeostasis and neurodevelopment. Other routes include the generation of oxidative stress, depletion of reduced glutathione, direct and indirect reductions in mitochondrial performance and integrity, and increasing the production of proinflammatory cytokines in both the brain and peripherally. The mechanisms whereby environmental aluminium could contribute to the development of the highly specific pattern of neuropathology seen in Alzheimer's disease are described. Also detailed are several mechanisms whereby significant quantities of aluminium introduced via immunisation could produce chronic neuropathology in genetically susceptible children. Accordingly, it is recommended that the use of aluminium salts in immunisations should be discontinued and that adults should take steps to minimise their exposure to environmental aluminium.

Appeal to fear in health care: appropriate or inappropriate?

AIM

This paper examines appeal to fear in general: its perceived positive aspects, its negative characteristics, its appropriate as well as its fallacious use.

BACKGROUND

Appeal to fear is a commonly used marketing method that attempts to change behaviour by creating anxiety in those receiving a fearful message. It is regularly used in public health initiatives such as anti-smoking, anti-drunk driving campaigns as well as in hypertension awareness campaigns. Some chiropractors appear to use appeal to fear to promote subluxation awareness and thereby encourage the use of chiropractic treatment. Research supporting its use is equivocal; nevertheless, when used judiciously, appeal to fear probably has sufficient strengths to warrant its continued conditional use. When used to promote care for which there is no supporting evidence, its use is fallacious.

DISCUSSION

Appeal to fear has been used in health promotion campaigns for sixty years or more with the intent of modifying behaviours. While there is evidence to suggest that appeal to fear may motivate some individuals to modify offending behaviour or adopt recommended behaviour there is growing resistance to the use of appeal to fear on ethical and psychological grounds. Using appeal to fear as a tool of persuasion can be valid or fallacious depending on the truth of the premises within the argument. When used to raise awareness about genuine health concerns such as smoking, drunk driving and hypertension appeal to fear is considered to be a valid approach with certain caveats. However, when appeal to fear, not based on evidence or reason, is used as motivator to get others to accept unnecessary interventions for unproven disorders, the use of appeal to fear is fallacious.

CONCLUSION

In spite of the evidence against its use, it seems likely that appeal to fear will continue to be used in conjunction with other public awareness initiatives to modify recognized detrimental behaviours such as smoking and drunk driving as well as silent killers such as hypertension. However, when used to promote a treatment that has no evidentiary basis such as subluxation based practice in chiropractic the appeal to fear is a fallacy and must be stopped.

The Reemergence of Measles

Measles, or rubeola, is a highly infectious, acute viral illness of childhood that is considered eliminated in the USA but has reemerged in the past few years. Globally, an estimated 20 million cases of measles continue to occur, and it remains a leading cause of death among young children. It is rare in the USA and other first world countries, but numerous outbreaks have occurred in the USA recently, due to a combination of factors including poor vaccine coverage and importation of cases among travelers returning from endemic areas. The diagnosis of measles is usually made clinically, when an individual presents with a constellation of symptoms including cough, coryza, conjunctivitis, high fever, and an erythematous maculopapular rash in a cephalocaudal distribution. Complications are common and include otitis media, pneumonia, encephalitis, and rarely death. A measles vaccine is available in two doses and provides excellent protection against the disease. Despite this, vaccination coverage, especially among young adults, remains poor. Given its resurgence in the USA and other countries, interventions are urgently needed to address low vaccination rates and vaccine hesitancy. Measles awareness should also be a priority among young clinicians, who may have never seen a case or are not familiar with the disease.

Vaccination in children with allergy to non active vaccine components

Childhood immunisation is one of the greatest public health successes of the last century. Vaccines contain an active component (the antigen) which induces the immune response. They may also contain additional components such as preservatives, additives, adjuvants and traces of other substances. This review provides information about risks of hypersensitivity reactions to components of vaccines. Furthermore, recommendations to avoid or reduce reactions to vaccine components have been detailed.

Factors associated with poor adherence to MMR vaccination in parents who follow vaccination schedule

Due to median vaccination coverage far from elimination level, Italy is still an European country with high number of measles cases per million of people. In this study we explored potential socioeconomic, medical and demographic factors which could influence the propensity of family members for measles vaccination schedule. A cross-sectional study was performed through a questionnaire administered to the parents of children who received the first dose of MMR vaccine in two different vaccination centers in the Palermo area from November 2012 to May 2013. Overall, the role played by internet (OR 19.8 P = 0.001) and the large number of children in a family (OR 7.3 P ≤ 0.001) were the factors more associated to be unvaccinated, whereas the birth order of the child (OR 0.3 P = < 0.05 for the oldest children vs. the closer young one) and reporting a lack of MMR vaccination as a "personal decision" (OR 0.19 P ≤ 0.01) inversely correlated with the risk of quitting vaccination. These findings can be useful for a better knowledge of disaffection to vaccination practice in local settings and could contribute to improve and maintain timely uptake, suggesting approaches to optimize the uptake of MMR tailored to the needs of local populations.

Environmental chemical exposures and autism spectrum disorders: a review of the epidemiological evidence

In the past decade, the number of epidemiological publications addressing environmental chemical exposures and autism has grown tremendously. These studies are important because it is now understood that environmental factors play a larger role in causing autism than previously thought and because they address modifiable risk factors that may open up avenues for the primary prevention of the disability associated with autism. In this review, we covered studies of autism and estimates of exposure to tobacco, air pollutants, volatile organic compounds and solvents, metals (from air, occupation, diet, dental amalgams, and thimerosal-containing vaccines), pesticides, and organic endocrine-disrupting compounds such as flame retardants, non-stick chemicals, phthalates, and bisphenol A. We included studies that had individual-level data on autism, exposure measures pertaining to pregnancy or the 1st year of life, valid comparison groups, control for confounders, and adequate sample sizes. Despite the inherent error in the measurement of many of these environmental exposures, which is likely to attenuate observed associations, some environmental exposures showed associations with autism, especially traffic-related air pollutants, some metals, and several pesticides, with suggestive trends for some volatile organic compounds (e.g., methylene chloride, trichloroethylene, and styrene) and phthalates. Whether any of these play a causal role requires further study. Given the limited scope of these publications, other environmental chemicals cannot be ruled out, but have not yet been adequately studied. Future research that addresses these and additional environmental chemicals, including their most common routes of exposures, with accurate exposure measurement pertaining to several developmental windows, is essential to guide efforts for the prevention of the neurodevelopmental damage that manifests in autism symptoms.

An Exploratory Survey for Understanding Perceptions, Knowledge and Educational Needs of General Practitioners (GSs) Regarding Autistic Disorders in New South Wales (NSW), Australia

AIM

A survey was conducted to ascertain General Practitioners (GPs') perceptions, knowledge and educational needs regarding autistic disorders in childhood.

METHODS

A concurrent mixed method approach was used for data collection and analysis. Exploratory factor analysis (EFA) of the data was done and groups were compared using appropriate statistical tests.

RESULTS

There was more response from female GPs, Australian medical graduates and those with an interest in mental and /or child health. Variability was noted in how GPs perceived their competence and knowledge of autistic disorders. About 60% correctly believed that an early-individualised treatment programme was evidence based. Knowledge was inversely related to the number of years in practice and enhanced by personal involvement with children of these disorders and awareness of community resources. Parallel analysis of knowledge scale revealed a "general knowledge" dimension loading items helpful for early identification and referral and a "surveillance" dimension helpful for ongoing involvement of GPs for management of children with ASDs.

CONCLUSIONS

Although further development and refinement of knowledge questionnaire using these dimensions for primary care physicians are needed these are relevant target areas for education.

An outbreak of measles in an undervaccinated community

Measles is readily spread to susceptible individuals, but is no longer endemic in the United States. In March 2011, measles was confirmed in a Minnesota child without travel abroad. This was the first identified case-patient of an outbreak. An investigation was initiated to determine the source, prevent transmission, and examine measles-mumps-rubella (MMR) vaccine coverage in the affected community. Investigation and response included case-patient follow-up, post-exposure prophylaxis, voluntary isolation and quarantine, and early MMR vaccine for non-immune shelter residents >6 months and <12 months of age. Vaccine coverage was assessed by using immunization information system records. Outreach to the affected community included education and support from public health, health care, and community and spiritual leaders. Twenty-one measles cases were identified. The median age was 12 months (range, 4 months to 51 years) and 14 (67%) were hospitalized (range of stay, 2-7 days). The source was a 30-month-old US-born child of Somali descent infected while visiting Kenya. Measles spread in several settings, and over 3000 individuals were exposed. Sixteen case-patients were unvaccinated; 9 of the 16 were age-eligible: 7 of the 9 had safety concerns and 6 were of Somali descent. MMR vaccine coverage among Somali children declined significantly from 2004 through 2010 starting at 91.1% in 2004 and reaching 54.0% in 2010 (χ(2) for linear trend 553.79; P < .001). This was the largest measles outbreak in Minnesota in 20 years, and aggressive response likely prevented additional transmission. Measles outbreaks can occur if undervaccinated subpopulations exist. Misunderstandings about vaccine safety must be effectively addressed.

Timely versus delayed early childhood vaccination and seizures

BACKGROUND

Little is known regarding the timing of childhood vaccination and postvaccination seizures.

METHODS

In a cohort of 323 247 US children from the Vaccine Safety Datalink born from 2004 to 2008, we analyzed the association between the timing of childhood vaccination and the first occurrence of seizure with a self-controlled case series analysis of the first doses of individual vaccines received in the first 2 years of life.

RESULTS

In infants, there was no association between the timing of infant vaccination and postvaccination seizures. In the second year of life, the incident rate ratio (IRR) for seizures after receipt of the first measles-mumps-rubella vaccine (MMR) dose at 12 to 15 months was 2.65 (95% confidence interval [CI] 1.99-3.55); the IRR after an MMR dose at 16 to 23 months was 6.53 (95% CI 3.15-13.53). The IRR for seizures after receipt of the first measles-mumps-rubella-varicella vaccine (MMRV) dose at 12 to 15 months was 4.95 (95% CI 3.68-6.66); the IRR after an MMRV dose at 16 to 23 months was 9.80 (95% CI 4.35 -22.06).

CONCLUSIONS

There is no increased risk of postvaccination seizure in infants regardless of timing of vaccination. In year 2, delaying MMR vaccine past 15 months of age results in a higher risk of seizures. The strength of the association is doubled with MMRV vaccine. These findings suggest that on-time vaccination is as safe with regard to seizures as delayed vaccination in the first year of life, and that delayed vaccination in the second year of life is associated with more postvaccination seizures than on-time vaccination.

Gestational/perinatal chlorpyrifos exposure is not associated with autistic-like behaviors in rodents

Although animal models cannot exactly replicate human psychiatric disorders, they may be useful to investigate whether the behaviors associated with certain exposures in animals parallel those observed in people. According to the most current version of the Diagnostic and Statistical Manual of Mental Disorders, autism is diagnosed based on (1) persistent deficits in social communication and social interaction; and (2) the presence of restricted, repetitive patterns of behavior, interests and activities. To address whether developmental chlorpyrifos (CPF) exposure was associated with the development of autistic behaviors, a literature search was conducted to identify studies in rats and mice involving gestational or early postnatal exposure to CPF or CPF oxon (CPO, the active metabolite of CPF) and subsequent behavioral testing to assess behaviors related to autism. A total of 13 studies conducted in six different laboratories were identified. Analysis of these studies found that perinatal CPF exposure was generally associated with (1) no effect or increased social communications; (2) no effect or increased social encounters; (3) no effect, reduced stereotypies, or conflicting findings on stereotypic behaviors; and (4) no effect or increased preference for novelty and reduced anxiety in novel environments. These behavioral findings are generally inconsistent with the types of behaviors that would be expected in children with clinical autism. Based on the results of this analysis of rodent model studies involving CPF/CPO exposure, it cannot be concluded that gestational and/or perinatal CPF exposure is likely to be associated with the development of autism-like behaviors in humans.

A comparative pharmacokinetic estimate of mercury in U.S. Infants following yearly exposures to inactivated influenza vaccines containing thimerosal

The use of thimerosal preservative in childhood vaccines has been largely eliminated over the past decade in the United States because vaccines have been reformulated in single-dose vials that do not require preservative. An exception is the inactivated influenza vaccines, which are formulated in both multidose vials requiring preservative and preservative-free single-dose vials. As part of an ongoing evaluation by USFDA of the safety of biologics throughout their lifecycle, the infant body burden of mercury following scheduled exposures to thimerosal preservative in inactivated influenza vaccines in the United States was estimated and compared to the infant body burden of mercury following daily exposures to dietary methylmercury at the reference dose established by the USEPA. Body burdens were estimated using kinetic parameters derived from experiments conducted in infant monkeys that were exposed episodically to thimerosal or MeHg at identical doses. We found that the body burden of mercury (AUC) in infants (including low birth weight) over the first 4.5 years of life following yearly exposures to thimerosal was two orders of magnitude lower than that estimated for exposures to the lowest regulatory threshold for MeHg over the same time period. In addition, peak body burdens of mercury following episodic exposures to thimerosal in this worst-case analysis did not exceed the corresponding safe body burden of mercury from methylmercury at any time, even for low-birth-weight infants. Our pharmacokinetic analysis supports the acknowledged safety of thimerosal when used as a preservative at current levels in certain multidose infant vaccines in the United States.

Vaccine perceptions among Oregon health care providers

Health care providers exert a significant influence on parental pediatric vaccination decisions. We conducted hour-long interviews with traditional and alternative health care providers in which we explored a range of associations between vaccination perceptions and practice. A key finding was that the Health Belief Model constructs of perceived susceptibility to and severity of either an illness or an adverse vaccine event partially explained health care provider (HCP) beliefs about the risks or benefits of vaccination, especially among alternative care providers. Low or high perceived susceptibility to a vaccine-preventable disease (VPD) or of the severity of a given VPD affects whether an HCP will promote or oppose pediatric vaccination recommendations. Beyond these perceptions, health and vaccination beliefs are affected by the contextual factors of personal experience, group norms, immunology beliefs, and beliefs about industry and government. Building powerful affective heuristics might be critical to balancing the forces that defeat good public health practices.

The Study to Explore Early Development (SEED): a multisite epidemiologic study of autism by the Centers for Autism and Developmental Disabilities Research and Epidemiology (CADDRE) network

The Study to Explore Early Development (SEED), a multisite investigation addressing knowledge gaps in autism phenotype and etiology, aims to: (1) characterize the autism behavioral phenotype and associated developmental, medical, and behavioral conditions and (2) investigate genetic and environmental risks with emphasis on immunologic, hormonal, gastrointestinal, and sociodemographic characteristics. SEED uses a case-control design with population-based ascertainment of children aged 2-5 years with an autism spectrum disorder (ASD) and children in two control groups-one from the general population and one with non-ASD developmental problems. Data from parent-completed questionnaires, interviews, clinical evaluations, biospecimen sampling, and medical record abstraction focus on the prenatal and early postnatal periods. SEED is a valuable resource for testing hypotheses regarding ASD characteristics and causes.

Cytokine dysregulation in autism spectrum disorders (ASD): possible role of the environment

Autism spectrum disorders (ASD) are neurodevelopmental diseases that affect an alarming number of individuals. The etiological basis of ASD is unclear, and evidence suggests it involves both genetic and environmental factors. There are many reports of cytokine imbalances in ASD. These imbalances could have a pathogenic role, or they may be markers of underlying genetic and environmental influences. Cytokines act primarily as mediators of immunological activity but they also have significant interactions with the nervous system. They participate in normal neural development and function, and inappropriate activity can have a variety of neurological implications. It is therefore possible that cytokine dysregulation contributes directly to neural dysfunction in ASD. Further, cytokine profiles change dramatically in the face of infection, disease, and toxic exposures. Imbalances in cytokines may represent an immune response to environmental contributors to ASD. The following review is presented in two main parts. First, we discuss select cytokines implicated in ASD, including IL-1Β, IL-6, IL-4, IFN-γ, and TGF-Β, and focus on their role in the nervous system. Second, we explore several neurotoxic environmental factors that may be involved in the disorders, and focus on their immunological impacts. This review represents an emerging model that recognizes the importance of both genetic and environmental factors in ASD etiology. We propose that the immune system provides critical clues regarding the nature of the gene by environment interactions that underlie ASD pathophysiology.

Measles

Measles is a highly contagious disease caused by measles virus and is one of the most devastating infectious diseases of man--measles was responsible for millions of deaths annually worldwide before the introduction of the measles vaccines. Remarkable progress in reducing the number of people dying from measles has been made through measles vaccination, with an estimated 164,000 deaths attributed to measles in 2008. This achievement attests to the enormous importance of measles vaccination to public health. However, this progress is threatened by failure to maintain high levels of measles vaccine coverage. Recent measles outbreaks in sub-Saharan Africa, Europe, and the USA show the ease with which measles virus can re-enter communities if high levels of population immunity are not sustained. The major challenges for continued measles control and eventual eradication will be logistical, financial, and the garnering of sufficient political will. These challenges need to be met to ensure that future generations of children do not die of measles.

Theoretical aspects of autism: causes--a review

Autism, a member of the pervasive developmental disorders (PDDs), has been increasing dramatically since its description by Leo Kanner in 1943. First estimated to occur in 4 to 5 per 10,000 children, the incidence of autism is now 1 per 110 in the United States, and 1 per 64 in the United Kingdom, with similar incidences throughout the world. Searching information from 1943 to the present in PubMed and Ovid Medline databases, this review summarizes results that correlate the timing of changes in incidence with environmental changes. Autism could result from more than one cause, with different manifestations in different individuals that share common symptoms. Documented causes of autism include genetic mutations and/or deletions, viral infections, and encephalitis following vaccination. Therefore, autism is the result of genetic defects and/or inflammation of the brain. The inflammation could be caused by a defective placenta, immature blood-brain barrier, the immune response of the mother to infection while pregnant, a premature birth, encephalitis in the child after birth, or a toxic environment.

Congenital rubella syndrome and autism spectrum disorder prevented by rubella vaccination--United States, 2001-2010

BACKGROUND

Congenital rubella syndrome (CRS) is associated with several negative outcomes, including autism spectrum disorders (ASDs). The objective of this study was to estimate the numbers of CRS and ASD cases prevented by rubella vaccination in the United States from 2001 through 2010.

METHODS

Prevention estimates were calculated through simple mathematical modeling, with values of model parameters determined from published literature. Model parameters included pre-vaccine era CRS incidence, vaccine era CRS incidence, the number of live births per year, and the percentage of CRS cases presenting with an ASD.

RESULTS

Based on our estimates, 16,600 CRS cases (range: 8300-62,250) were prevented by rubella vaccination from 2001 through 2010 in the United States. An estimated 1228 ASD cases were prevented by rubella vaccination in the United States during this time period. Simulating a slight expansion in ASD diagnostic criteria in recent decades, we estimate that a minimum of 830 ASD cases and a maximum of 6225 ASD cases were prevented.

CONCLUSIONS

We estimate that rubella vaccination prevented substantial numbers of CRS and ASD cases in the United States from 2001 through 2010. These findings provide additional incentive to maintain high measles-mumps-rubella (MMR) vaccination coverage.

Willingness of pregnant women to vaccinate themselves and their newborns with the HPV vaccine

OBJECTIVE

To evaluate the willingness of pregnant women to accept the HPV vaccine for their newborns as well as themselves.

METHODS

An 18-item questionnaire was distributed to antepartum women. Demographic data about the respondent's current pregnancy and her knowledge of HPV and the HPV vaccine was collected. Information about the respondent's HPV and HPV vaccine status as well as her acceptance of the vaccine for herself during pregnancy and her newborn son and/or daughter after delivery was also collected.

RESULTS

Three hundred surveys were completed and available for review. Only 6 respondents (2%) had received the HPV vaccine. Despite the small group of patients who had previously been vaccinated, 112 respondents (37.3%) stated that they would receive the HPV vaccine during pregnancy if recommended by an obstetrician. 99 respondents (33%) stated that they would vaccinate their newborn female infant and 83 (27.7%) stated would vaccinate their male infants.

CONCLUSION

Providing the HPV vaccine to pregnant women as well as newborns could be an important way to increase the patient population who is protected against HPV. A percentage of pregnant women are willing to accept the vaccine for themselves and their newborns.

The Vaccine Safety Datalink: a model for monitoring immunization safety

The Vaccine Safety Datalink (VSD) project is a collaborative project between the Centers for Disease Control and Prevention and 8 managed care organizations (MCOs) in the United States. Established in 1990 to conduct postmarketing evaluations of vaccine safety, the project has created an infrastructure that allows for high-quality research and surveillance. The 8 participating MCOs comprise a large population of 8.8 million members annually (3% of the US population), which enables researchers to conduct studies that assess adverse events after immunization. Each MCO prepares computerized data files by using a standardized data dictionary containing demographic and medical information on its members, such as age and gender, health plan enrollment, vaccinations, hospitalizations, outpatient clinic visits, emergency department visits, urgent care visits, and mortality data, as well as additional birth information (eg, birth weight) when available. Other information sources, such as medical chart review, member surveys, and pharmacy, laboratory, and radiology data, are often used in VSD studies to validate outcomes and vaccination data. Since 2000, the VSD has undergone significant changes including an increase in the number of participating MCOs and enrolled population, changes in data-collection procedures, the creation of near real-time data files, and the development of near real-time postmarketing surveillance for newly licensed vaccines or changes in vaccine recommendations. Recognized as an important resource in vaccine safety, the VSD is working toward increasing transparency through data-sharing and external input. With its recent enhancements, the VSD provides scientific expertise, continues to develop innovative approaches for vaccine-safety research, and may serve as a model for other patient safety collaborative research projects.

Parent preferences for pediatric influenza vaccine attributes

Influenza vaccine is available as an intramuscular injection or an intranasal spray for eligible children. This study was conducted to examine parents' preferences for influenza vaccine attributes and the attributes' relative importance regarding the vaccination of their children. A quantitative Web survey was administered to 500 parents of children aged 2 to 12 years. The survey included general preference questions and conjoint (trade-off) questions. Parents most frequently selected efficacy, risk of temporary side effects, and physician recommendation as important vaccine attributes from a provided list (92%, 75%, and 59%, respectively). For attributes selected as important, parents rated the importance of the attribute; the highest mean importance ratings were given to efficacy, presence of mercury-containing preservative, and physician recommendation.The highest relative importance ratings in the conjoint section were given to efficacy and presence of mercury-containing preservative. Parental education on influenza vaccine efficacy and safety may help to improve pediatric vaccination rates.

Attitudinal and demographic predictors of measles, mumps and rubella (MMR) vaccine acceptance: development and validation of an evidence-based measurement instrument

BACKGROUND AND OBJECTIVE

Parents' attitudes toward MMR vaccine and measles, mumps and rubella infections relate to their child's MMR status, therefore improving these attitudes is central to improving current suboptimal MMR uptake. However, no study has yet combined evidence-based, comprehensive and psychometrically validated assessment of these attitudes with reliable objective MMR status data, in order to identify through multivariate analyses the strongest attitudinal predictors of MMR uptake for interventions to target. The present study fills this lacuna by developing and testing a robust evidence-based MMR attitudes measurement instrument.

DESIGN

Cross-sectional self-administered postal/telephone questionnaire with objective behavioural outcome.

SETTING AND PARTICIPANTS

535 parents of children aged 5-18 in London and north-west England, UK (response rate 18.1%). Recruitment via Primary Care Trust records, age-stratified purposive sample with suboptimally immunised cases oversampled.

MAIN OUTCOME MEASURES

Parents' responses to evidence-based measurement instrument comprising 20 attitude/previous behaviour items (collapsing to 5 scales) and 7 demographic items, and their children's PCT-recorded 5th birthday status for MMR dose 1 (on-time, late or none) and MMR dose 2 (on-time or none).

RESULTS

The attitudes measurement instrument was psychometrically robust: content valid, and demonstrating good or acceptable internal consistency (Cronbach's alpha=0.55-0.75 for all scales), test-retest reliability (Pearson's correlation >0.60-0.80, p<0.01 to <0.001 for all scales and 11 individual items), concurrent/construct validity (t-tests for difference between MMR status groups p<0.05 for four scales and thirteen individual items), and predictive/criterion validity (OR=0.66, 95% confidence interval=0.48-0.92 to OR=1.97, 95% CI=1.18-3.31 for three scales and five individual items). Black and minority ethnicity (OR=1.94, 95% CI=1.15-3.30 to OR=4.15, 95% CI=2.40-7.19), positive MMR attitudes (OR=1.63, 95% CI=1.00-2.66 to OR=1.97, 95% CI=1.18-1.31), and positive social attitudes (OR=1.64, 95% CI=1.23-2.40 to OR=1.72, 95% CI=1.13-2.38) independently predicted uptake for both MMR doses. MMR status groups differed most strongly on preference for single measles, mumps and rubella vaccines (6-9% variance in status explained), previous MMR acceptance/rejection (5-9%), and wishing to protect others through vaccinating one's own child (6-8%).

CONCLUSIONS

The measurement instrument is robust on multiple validity and reliability dimensions, and is appropriate for use in research and practice as a tool for designing and evaluating interventions. Parents appear to act in line with their attitudes toward MMR vaccine, though attitudes toward measles infection bore little relation to MMR uptake. This study indicates populations and attitudes to be prioritized in MMR uptake improvement interventions.

Monitoring and assessing vaccine safety: a European perspective

The success of vaccination programs is an uncontroversial reality--in Europe as well as worldwide. On the other hand, the perceived risk of adverse events in the general public is the most important threat for implementing successful vaccination programs in Europe. For this reason, monitoring and assessing vaccine safety is a priority for public health. Vaccine safety is assessed both before and after vaccine authorization. In postmarketing settings, different activities related to vaccine safety usually involve several different stakeholders. In 2005, a new EU agency, the European Centre for Disease Prevention and Control, was established with the aim to strengthen Europe's defences against infectious diseases. Implementing stable links between different stakeholders and defining clear roles in the EU is paramount in order to provide optimal and transparent information on adverse reactions following immunization, with the final goal of increasing compliance to safe and effective vaccination programs.

Mercury induces inflammatory mediator release from human mast cells

Background

Mercury is known to be neurotoxic, but its effects on the immune system are less well known. Mast cells are involved in allergic reactions, but also in innate and acquired immunity, as well as in inflammation. Many patients with Autism Spectrum Disorders (ASD) have "allergic" symptoms; moreover, the prevalence of ASD in patients with mastocytosis, characterized by numerous hyperactive mast cells in most tissues, is 10-fold higher than the general population suggesting mast cell involvement. We, therefore, investigated the effect of mercuric chloride (HgCl₂) on human mast cell activation.

Methods

Human leukemic cultured LAD2 mast cells and normal human umbilical cord blood-derived cultured mast cells (hCBMCs) were stimulated by HgCl2 (0.1-10 μM) for either 10 min for beta-hexosaminidase release or 24 hr for measuring vascular endothelial growth factor (VEGF) and IL-6 release by ELISA.

Results

HgCl₂ induced a 2-fold increase in β-hexosaminidase release, and also significant VEGF release at 0.1 and 1 μM (311 ± 32 pg/10⁶ cells and 443 ± 143 pg/10⁶ cells, respectively) from LAD2 mast cells compared to control cells (227 ± 17 pg/10⁶ cells, n = 5, p < 0.05). Addition of HgCl₂ (0.1 μM) to the proinflammatory neuropeptide substance P (SP, 0.1 μM) had synergestic action in inducing VEGF from LAD2 mast cells. HgCl₂ also stimulated significant VEGF release (360 ± 100 pg/10⁶ cells at 1 μM, n = 5, p < 0.05) from hCBMCs compared to control cells (182 ± 57 pg/10⁶ cells), and IL-6 release (466 ± 57 pg/10⁶ cells at 0.1 μM) compared to untreated cells (13 ± 25 pg/10⁶ cells, n = 5, p < 0.05). Addition of HgCl₂ (0.1 μM) to SP (5 μM) further increased IL-6 release.

Conclusions

HgCl₂ stimulates VEGF and IL-6 release from human mast cells. This phenomenon could disrupt the blood-brain-barrier and permit brain inflammation. As a result, the findings of the present study provide a biological mechanism for how low levels of mercury may contribute to ASD pathogenesis.

Fundamentals of clinical immunotoxicology

Whereas animal studies are invaluable for screening various chemical and drugs for immunotoxic potential, such systems are necessarily limited in their predictive value for humans given the differences in physiology, immune system structure and function, and various other parameters between humans and nonhuman animals. However, prospective experimental studies in humans are not always practical or ethical. What is needed is an approach for combining animal data, human data collected in the course of clinical studies, and modern tools of bioinformatics and systems biology. In this chapter, we will explore current assays and methodologies for assessing immunotoxic potential in humans using this multi--parameter approach.

Autism: an emerging 'neuroimmune disorder' in search of therapy

BACKGROUND

Autism spectrum disorders (ASDs) are neurodevelopmental disorders characterized by difficulties in communication and by repetitive and stereotypic behaviors, as well as by social impairment, attention, cognitive, and learning defects. ASDs present in early childhood and their prevalence has increased significantly to 1/150 children. Despite a number of theories, the actual reasons for this increase are still not clear. There is no reliable screening test, and no definite pathogenesis or curative therapy. Consequently, there is a major gap hampering development of effective treatments.

OBJECTIVE

To review recent publications on ASDs pathogenesis and treatment with emphasis on neuroimmune processes and new therapeutic approaches.

METHODS

Mostly original papers (450) on epidemiology, possible pathogenesis or treatment of ASDs in Medline from 1990 to May 2009 were reviewed. All authors contributed to this review.

RESULTS/CONCLUSION

Increased oxidative stress and immune dysregulation are present in ASDs. Mast-cell activation may contribute to gut-blood-brain barrier disruption and brain inflammation. No effective treatments have emerged. Well-designed clinical trials with nonpsychotropic drugs were few and ASD characteristics varied considerably, making conclusions difficult. Psychotropic drugs are often used for stereotypic and aggressive behaviors. Unique combinations with antioxidant and anti-inflammatory flavonoids hold promise. New potential translational research areas and possible treatments are suggested.