Correlates of high vaccination exemption rates among kindergartens

Referrals and Determinant Factors of a National School Health Campaign in Lebanon on Children Aged between 3 and 12 Years Old

In this extensive study examining the health of 7184 school children aged 3 to 12 in 27 Lebanese schools, screenings involved medical evaluation and interviews, complemented by phone interviews with 3880 parents. Notably, one in two students received a medical referral, revealing prevalent issues such as dental cavities (33%), under-vaccination (25%), undetected vision problems (13%), abnormal growth (6%), underweight (27%), and overweight (33%). Additional concerns encompassed abnormal vital signs (3%), abuse signs (0.6%), infectious skin lesions (1.6%), scoliosis (1.7%), abnormal auscultation (heart 1.1%, lungs 1.2%), ear problems (3.3%), precocious puberty (0.7%), and neurologic signs (0.6%). Mental health challenges affected 20-25% of students. Public schools and Beirut exhibited higher referral rates, with girls, older children, overweight students, those lacking regular pediatrician visits, and children of self-employed or less educated parents facing elevated referral rates. In contrast, children of healthcare workers experienced fewer referrals. Against this backdrop, the study emphasizes the imperative for targeted health initiatives, particularly in marginalized areas and for socioeconomically disadvantaged students. Priority areas include dental care, weight issues, mental health, vaccination compliance, and addressing vision problems to enhance learning outcomes.

Spatial distribution and determinants of childhood vaccination refusal in the United States

Parental refusal and delay of childhood vaccination has increased in recent years in the United States. This phenomenon challenges maintenance of herd immunity and increases the risk of outbreaks of vaccine-preventable diseases. We examine US county-level vaccine refusal for patients under five years of age collected during the period 2012-2015 from an administrative healthcare dataset. We model these data with a Bayesian zero-inflated negative binomial regression model to capture social and political processes that are associated with vaccine refusal, as well as factors that affect our measurement of vaccine refusal. Our work highlights fine-scale socio-demographic characteristics associated with vaccine refusal nationally, finds that spatial clustering in refusal can be explained by such factors, and has the potential to aid in the development of targeted public health strategies for optimizing vaccine uptake.

Spatial clustering in vaccination hesitancy: The role of social influence and social selection

The phenomenon of vaccine hesitancy behavior has gained ground over the last three decades, jeopardizing the maintenance of herd immunity. This behavior tends to cluster spatially, creating pockets of unprotected sub-populations that can be hotspots for outbreak emergence. What remains less understood are the social mechanisms that can give rise to spatial clustering in vaccination behavior, particularly at the landscape scale. We focus on the presence of spatial clustering, and aim to mechanistically understand how different social processes can give rise to this phenomenon. In particular, we propose two hypotheses to explain the presence of spatial clustering: (i) social selection, in which vaccine-hesitant individuals share socio-demographic traits, and clustering of these traits generates spatial clustering in vaccine hesitancy; and (ii) social influence, in which hesitant behavior is contagious and spreads through neighboring societies, leading to hesitant clusters. Adopting a theoretical spatial network approach, we explore the role of these two processes in generating patterns of spatial clustering in vaccination behaviors under a range of spatial structures. We find that both processes are independently capable of generating spatial clustering, and the more spatially structured the social dynamics in a society are, the higher spatial clustering in vaccine-hesitant behavior it realizes. Together, we demonstrate that these processes result in unique spatial configurations of hesitant clusters, and we validate our models of both processes with fine-grain empirical data on vaccine hesitancy, social determinants, and social connectivity in the US. Finally, we propose, and evaluate the effectiveness of two novel intervention strategies to diminish hesitant behavior. Our generative modeling approach informed by unique empirical data provides insights on the role of complex social processes in driving spatial heterogeneity in vaccine hesitancy.

Geographic disparities and predictors of vaccination exemptions in Florida: a retrospective study

BACKGROUND

In the United States, state-level policies requiring vaccination of school-going children constitute a critical strategy for improving vaccination coverage. However, policies allowing vaccination exemptions have also been implemented and contribute to reductions in vaccination coverage and potential increases in the burden of vaccine-preventable diseases. Understanding the geographic disparities in the distribution of vaccination exemptions and identifying high risk areas is necessary for guiding resource allocation and public health control strategies. This study investigated geographic disparities in vaccination exemptions as well as socioeconomic and demographic predictors of vaccination exemptions in Florida.

METHODS

Vaccination exemption data were obtained from the Florida Department of Health's Florida HealthCHARTS web interface. Spatial patterns in geographic distribution of total and non-medical vaccination exemptions were assessed using county-level choropleth maps. Negative binomial models were used to identify significant predictors of county-level risks of both total and non-medical vaccination exemptions.

RESULTS

Total exemptions varied from 0 to 30.2 per 10,000 people. Nine counties had exemption risks in the top two classes (10.4-15.9 and 15.9-30.2 exemptions per 10,000 people). These counties were distributed in five distinct areas: Western Panhandle, central northern area, central, South-eastern coastal area, and the southern coastal border of the state. Non-medical exemptions varied from 0 to 10.4 per 10,000 people. Fifteen counties had exemption risks in the top two classes (3.7-5.6 and 5.6-10.4 exemptions per 10,000 people), and were located in six distinct areas: Western and Central Panhandle, Northeastern, Central-eastern coastal area, Central-western coastal area, and the South-western coastal border of the state. Predictors of high risk of total vaccination exemptions were high density of primary care providers (p < 0.001), high median income (p = 0.001), high percentage of Hispanic population (p = 0.046), and low percentage of population with a college education (p = 0.013). A predictor of high risk of non-medical vaccination exemptions was high percentage of White population (p = 0.045). However, predictors of low risks of non-medical exemptions were high percentages of population: living in rural areas (p = 0.023), with college education (p = 0.013), with high school education (p = 0.009), and with less than high school education (p < 0.001).

CONCLUSIONS

There is evidence of county-level geographic disparities in both total and non-medical vaccination exemption risks in Florida. These disparities are explained by differences in county-level socioeconomic and demographic factors. Study findings are important in guiding resource allocation for health planning aimed at improving vaccination rates and reducing incidence of vaccine-preventable diseases.

Evaluating public acceptability of a potential Lyme disease vaccine using a population-based, cross-sectional survey in high incidence areas of the United States

BACKGROUND

Lyme disease incidence is increasing, despite current prevention options. New Lyme disease vaccine candidates are in development, however, investigation of the acceptability of a Lyme disease vaccine among potential consumers is needed prior to any vaccine coming to market. We conducted a population-based, cross-sectional study to estimate willingness to receive a potential Lyme disease vaccine and factors associated with willingness.

METHODS

The web-based survey was administered to a random sample of Connecticut, Maryland, Minnesota, and New York residents June-July 2018. Survey-weighted descriptive statistics were conducted to estimate the proportion willing to receive a potential Lyme disease vaccine. Multivariable multinomial logistic regression models were used to quantify the association of sociodemographic characteristics and Lyme disease vaccine attitudes with willingness to be vaccinated.

RESULTS

Surveys were completed by 3313 respondents (6% response rate). We estimated that 64% of residents were willing to receive a Lyme disease vaccine, while 30% were uncertain and 7% were unwilling. Compared to those who were willing, those who were uncertain were more likely to be parents, adults 45-65 years old, non-White, have less than a bachelor's degree, or have safety concerns about a potential Lyme disease vaccine. Those who were unwilling were also more likely to be non-White, have less than a bachelor's degree, or have safety concerns about a potential Lyme disease vaccine. In addition, the unwilling had low confidence in vaccines in general, had low perceived risk of contracting Lyme disease, and said they would not be influenced by a positive recommendation from a healthcare provider.

DISCUSSION

Overall, willingness to receive a Lyme disease vaccine was high. Effective communication by clinicians regarding safety and other vaccine parameters to those groups who are uncertain will be critical for increasing vaccine uptake and reducing Lyme disease incidence.

The geographic distribution of un-immunized children in Ontario, Canada: Hotspot detection using Bayesian spatial analysis

BACKGROUND

In Ontario, Canada, little is currently known about the extent to which un-immunized children may cluster geographically. Our objectives were to: describe the geographic distribution of fully un-immunized children; identify geographic clusters (hotspots) of un-immunized children; and to characterize the contribution of spatial effects and covariates on hotspots, where found.

METHODS

Our analytic cohort consisted of Ontario students aged 7-17 years in the 2016-2017 school year. We defined students as un-immunized if they had zero doses of any vaccine and a non-medical exemption recorded in Ontario's registry. We calculated unadjusted proportions of un-immunized students by Census Subdivision (CSD) and then used a sequential approach to identify hotspots starting first with hotspot identification at the CSD level and then probed identified hotspots further by Dissemination Area (DA) and including covariates. Hotspots were identified using the Besag-York-Mollie Bayesian spatial model and were defined as areas with >95% probability of having two times the proportion of un-immunized students, relative to the province overall.

RESULTS

We identified 15,208 (0.94%) un-immunized children within our cohort consisting of more than 1.61 million students. Unadjusted proportions of un-immunized students varied greatly by geography, ranging from 0% to 21.5% by CSD. We identified 16 hotspot CSDs which clustered in five distinct areas, all of which were located in southern Ontario. The contribution of covariates and spatial effects on the risk of having un-immunized students varied greatly across hotspot areas.

CONCLUSIONS

Although the provincial proportion (0.94%) of un-immunized students is small, geographical clustering of such students is evident in Ontario and in some areas presents an important risk for future outbreaks. Further qualitative work within these hotspot areas would be a helpful next step to better characterize the factors associated with vaccine refusal in these communities.

Parents' knowledge, attitude and practice towards children's vaccination in Lebanon: role of the parent-physician communication

Background

One of the most effective public health interventions in the world is immunization. However, some parents doubt its usefulness and safety. Many factors influence their decision to vaccinate, including their sociodemographic characteristics, their trust in the public health system, the parent-physician relationship, their level of knowledge and their attitudes towards vaccination. Our objective was to determine the factors, especially the parent-physician communication, associated with parental knowledge, attitudes and practices of their children’s vaccination.

Methods

Three thousand five hundred parents (father, mother or both) of children aged between 1 month and 15 years were approached by a trained personnel who performed the data collection through personal interviews (February–April 2019).

Results

The response rate was 79.5%. The results of the multivariable analysis showed that a better patient-physician communication was significantly associated with higher knowledge, better attitude and practice. Better knowledge was significantly associated with better attitude, whereas better knowledge and attitude were significantly associated with better practice.

Conclusion

Our study shows the importance of good physician-patient communication in improving knowledge, attitude and practice of parents towards their children’s vaccination.

Trends in school-level vaccination coverage from 2015 to 2018: Increases in exemption rates and declines in herd immunity in Arizona

Vaccination enrollment requirements are an important tool used to improve vaccination coverage among school-aged children. However, all states permit varying exemptions that allow students to stay enrolled without receiving some (or all) vaccinations. In Arizona, schools are required to report vaccination data on their kindergarten and 6th grade students annually to the Arizona Department of Health Services (ADHS). We analyzed trends in herd immunity and personal belief exemptions in Arizona schools from 2015 to 2018. We also identified multiple correlates of herd immunity at the school level. Our results demonstrate decreased herd immunity statewide and by school type and an increased rate of personal belief exemptions during this period. These findings contribute to the body of literature suggesting that vaccine hesitancy is growing, resulting in suboptimal vaccination coverage for children. Moreover, this research has several policy implications, especially for states permitting multiple exemption types and lax exemption criteria.

Conscientious vaccination exemptions in kindergarten to eighth-grade children across Texas schools from 2012 to 2018: A regression analysis

BACKGROUND

As conscientious vaccination exemption (CVE) percentages rise across the United States, so does the risk and occurrence of outbreaks of vaccine-preventable diseases such as measles. In the state of Texas, the median CVE percentage across school systems more than doubled between 2012 and 2018. During this period, the proportion of schools surpassing a CVE percentage of 3% rose from 2% to 6% for public schools, 20% to 26% for private schools, and 17% to 22% for charter schools. The aim of this study was to investigate this phenomenon at a fine scale.

METHODS AND FINDINGS

Here, we use beta regression models to study the socioeconomic and geographic drivers of CVE trends in Texas. Using annual counts of CVEs at the school system level from the 2012-2013 to the 2017-2018 school year, we identified county-level predictors of median CVE percentage among public, private, and charter schools, the proportion of schools below a high-risk threshold for vaccination coverage, and five-year trends in CVEs. Since the 2012-2013 school year, CVE percentages have increased in 41 out of 46 counties in the top 10 metropolitan areas of Texas. We find that 77.6% of the variation in CVE percentages across metropolitan counties is explained by median income, the proportion of the population that holds a bachelor's degree, the proportion of the population that self-reports as ethnically white, the proportion of the population that is English speaking, and the proportion of the population that is under the age of five years old. Across the 10 top metropolitan areas in Texas, counties vary considerably in the proportion of school systems reporting CVE percentages above 3%. Sixty-six percent of that variation is explained by the proportion of the population that holds a bachelor's degree and the proportion of the population affiliated with a religious congregation. Three of the largest metropolitan areas-Austin, Dallas-Fort Worth, and Houston-are potential vaccination exemption "hotspots," with over 13% of local school systems above this risk threshold. The major limitations of this study are inconsistent school-system-level CVE reporting during the study period and a lack of geographic and socioeconomic data for individual private schools.

CONCLUSIONS

In this study, we have identified high-risk communities that are typically obscured in county-level risk assessments and found that public schools, like private schools, are exhibiting predictable increases in vaccination exemption percentages. As public health agencies confront the reemerging threat of measles and other vaccine-preventable diseases, findings such as ours can guide targeted interventions and surveillance within schools, cities, counties, and sociodemographic subgroups.

Measles outbreaks and public attitudes towards vaccine exemptions: some cautions and strategies for addressing vaccine hesitancy

Today, the United States and countries throughout the world are experiencing measles outbreaks that have sickened thousands of children. From the Disneyland outbreak in 2014 to today, some states have responded with changes in laws on vaccine requirements and exemptions. In this article, we examine the history of vaccine laws, and using our 2015 survey data, explore to what extent the news coverage of the Disneyland outbreak altered parents' attitudes toward required vaccination and non-medical exemptions. We explore those results in the context of today's increasing polarized and politicalized battle over vaccine laws, and consider how health care providers and policy makers can work to improve public attitudes about vaccines.

A cross-country study of mis-implementation in public health practice

BACKGROUND

Mis-implementation (i.e., the premature termination or inappropriate continuation of public health programs) contributes to the misallocation of limited public health resources and the sub-optimal response to the growing global burden of chronic disease. This study seeks to describe the occurrence of mis-implementation in four countries of differing sizes, wealth, and experience with evidence-based chronic disease prevention (EBCDP).

METHODS

A cross-sectional study of 400 local public health practitioners in Australia, Brazil, China, and the United States was conducted from November 2015 to April 2016. Online survey questions focused on how often mis-termination and mis-continuation occur and the most common reasons programs end and continue.

RESULTS

We found significant differences in knowledge of EBCDP across countries with upwards of 75% of participants from Australia (n = 91/121) and the United States (n = 83/101) reporting being moderately to extremely knowledgeable compared with roughly 60% (n = 47/76) from Brazil and 20% (n = 21/102) from China (p < 0.05). Far greater proportions of participants from China thought effective programs were never mis-terminated (12.2% (n = 12/102) vs. 1% (n = 2/121) in Australia, 2.6% (n = 2/76) in Brazil, and 1.0% (n = 1/101) in the United States; p < 0.05) or were unable to estimate how frequently this happened (45.9% (n = 47/102) vs. 7.1% (n = 7/101) in the United States, 10.5% (n = 8/76) in Brazil, and 1.7% (n = 2/121) in Australia; p < 0.05). The plurality of participants from Australia (58.0%, n = 70/121) and the United States (36.8%, n = 37/101) reported that programs often mis-continued whereas most participants from Brazil (60.5%, n = 46/76) and one third (n = 37/102) of participants from China believed this happened only sometimes (p < 0.05). The availability of funding and support from political authorities, agency leadership, and the general public were common reasons programs continued and ended across all countries. A program's effectiveness or evidence-base-or lack thereof-were rarely reasons for program continuation and termination.

CONCLUSIONS

Decisions about continuing or ending a program were often seen as a function of program popularity and funding availability as opposed to effectiveness. Policies and practices pertaining to programmatic decision-making should be improved in light of these findings. Future studies are needed to understand and minimize the individual, organizational, and political-level drivers of mis-implementation.

Association of Presence of a School Nurse With Increased Sixth-Grade Immunization Rates in Low-Income Arizona Schools in 2014-2015

School nurses often play large roles in implementation of school vaccination requirements aimed at controlling the spread of communicable disease. We analyzed the association between the presence of a school nurse and school-level vaccination rates in Arizona. Using school-level data from Arizona sixth-grade schools (n = 749), we regressed average sixth-grade school-level immunization rates on presence of a school nurse (registered nurse [RN] or licensed practical nurse [LPN]) and school-level socioeconomic status (SES), controlling for other school- and district-level characteristics. Schools with a nurse had higher overall vaccination rates than those without a nurse (96.1% vs. 95.0%, p < .01). For schools in the lowest SES quartile, the presence of a school nurse was associated with approximately 2 percentage point higher immunization rates. These findings add to the growing literature that defines the impact of school nurses on student health status and outcomes, emphasizing the value of school nurses, especially in lower SES schools.

An Ounce of Prevention: Identifying Cues to (In)Action for Maternal Vaccine Refusal

Recent increases in childhood vaccine exemption rates are a source of concern within the public health community. Drawing from the health belief model and in-depth interviews with 50 mothers ( n = 50) who refused one or more vaccine, the aim of this study was to identify the specific reasons and the broader decision context(s) that underscored participants' vaccine refusal. Results indicate that the vast majority of participants supported vaccination until a particular cue motivated them to consider otherwise, and qualitative analysis identified three main categories into which these cues fell: perceived adverse reactions, endorsements from health care professionals, and perceived contradiction among expert-endorsed messages. These categories point to the central role of health communication in motivating vaccine refusal. Better understanding these cues can inform vaccine communication scholarship and practice, and also lend theoretical insight into the intertextual nature of controversial health messages and decisions.

A Review of Traditional Vaccine-Preventable Diseases and the Potential Impact on the Otolaryngologist

Introduction  A majority of otolaryngologists have not had direct experience with many vaccine-preventable diseases since the creation of national vaccination programs. Despite the elimination of endemic transmission of some of these diseases in the United States, outbreaks can occur anywhere and still pose a threat to public health around the world. Recent outbreaks and changing trends in exemption rates indicate that it is important for physicians to maintain a working knowledge of how these diseases present and of the recommended treatment guidelines. Objectives  This review will evaluate the current state of vaccination rates, vaccine exemption rates and disease incidence in the United States and in the world. It will also examine the clinical presentation and treatment recommendations of these diseases. Data Synthesis  United States estimated vaccination rates, vaccine exemption rates and vaccine-preventable disease incidences were obtained from data compiled by the Centers for Disease Control and Prevention. World vaccination rates and disease incidences were obtained from the World Health Organization databases, which compile official figures reported by member states. A PubMed literature review provided information on the current state of vaccination exemptions and outbreaks in the United States. Conclusion  Vaccination and vaccine exemption rates continue to put the United States and many areas of the world at risk for outbreaks of vaccine-preventable diseases. Clinical guidelines should be reviewed in the event of a local outbreak.

Parental attitudes and perceptions associated with childhood vaccine exemptions in high-exemption schools

Previous work demonstrates that individuals who obtain exemptions from school immunization requirements are geographically clustered, making regional differences in vaccination coverage a significant concern. Even where exemption levels are high, there are still parents that vaccinate. School-level assessments have determined that exemptors are more likely to attend wealthier schools with fewer minorities. Few studies have assessed divergent opinions within the context of a higher-exemption community to examine subtle differences in opinion surrounding vaccinations. Therefore, the objective of this work was to assess attitudes and perceptions towards vaccinations and compare them for exemptors and non-exemptors. We administered surveys to parents in high-exemption (>10%) elementary schools in Arizona during the 2012–13 school year. A total of 404 surveys were completed by parents among schools in Maricopa (n = 7) and Yavapai (n = 2) counties. Of these, 35% (n = 141) were exemptors and 65% (n = 261) were non-exemptors. Exemptors were more likely than non-exemptors to be concerned about serious side-effects (p<0.001). They were more likely to report knowing someone who had been diagnosed with a vaccine-preventable disease (p<0.001) but less likely to report that this had been a serious illness in that person (p<0.001) and they believed it is better for a child to develop immunity through illness than vaccination (p<0.001). They were less likely to trust physicians (p<0.001) and information about vaccines (p<0.001) and were more likely to obtain their health care from a naturopath (p<0.001). In summary, exemptors in these Arizona schools do not appear to be exempting their children from vaccinations due to convenience, as has been hypothesized in other settings. Based on the divergent views within high-exemption schools and reported distrust of the medical establishment, target interventions for high-exemption schools are discussed. Additionally, given the lack of effective non-policy based interventions to-date, the negligible declines in personal belief exemption rates, and vaccine preventable disease rate increases in Arizona, especially in high-exemption areas, legislative action in Arizona may also warrant further investigation.

Impact of publicly available vaccination rates on parental school and child care choice

OBJECTIVE

Several states require schools and child cares to report vaccination rates, yet little is known about the impact of these policies. Our objectives were to assess: (1) predicted impact of vaccination rates on school/child care choice, (2) differences between vaccine hesitant and non-hesitant parents, and (3) differences by child's age.

METHODS

In 2016, a cross-sectional email survey of Colorado mothers with children ≤12 years old assessed value of vaccination rates in the context of school/child care choice. A willingness-to-pay framework measured preference for schools/child cares with different vaccination rates using tradeoff with commute time.

RESULTS

Response rate was 42% (679/1630). Twelve percent of respondents were vaccine hesitant. On a scale where 1 is "not important at all" and 4 is "very important" parents rated the importance of vaccination rates at 3.08. Respondents (including vaccine-hesitant respondents) would accept longer commutes to avoid schools/child cares with lower vaccination rates. Parents of child-care-age children were more likely to consider vaccination rates important.

CONCLUSIONS

This study shows parents highly value vaccination rates in the context of school and child care choice. Both hesitant and non-hesitant parents are willing to accept longer commute times to protect their children from vaccine-preventable diseases.

Mumps: Resurgence of a once-dormant disease

Mumps is a systemic viral illness, preventable by vaccination, that typically affects children and is characterized by unilateral or bilateral swelling of the parotid glands. Uncommon complications such as orchitis, oophoritis, deafness, pancreatitis, aseptic meningitis, and encephalitis occur more often in adults. Recent outbreaks of the disease appear to be caused by a failure to maintain herd immunity in certain populations, particularly in affluent white communities. This article reviews the clinical manifestations, diagnosis, and potential complications in patients with mumps.

Prevalence of Vaccine Hesitancy Among Expectant Mothers in Houston, Texas

OBJECTIVE

Nonmedical exemptions continue to rise because of increasing proportions of vaccine-hesitant parents. The proportion of expectant parents who are vaccine-hesitant is currently unknown. We assessed the prevalence of vaccine hesitancy among expectant parents receiving care at an obstetrics clinic in Houston, Texas.

METHODS

We conducted a cross-sectional survey of expectant parents between 12 and 31 weeks gestation who received care at Texas Children's Pavilion for Women between July 2014 and September 2015. Using convenience sampling, participants completed a questionnaire that included questions on demographic items, self-assessed pregnancy risk, receipt of annual influenza vaccine, and the 15-item Parents Attitudes About Childhood Vaccines survey, a validated tool to identify vaccine-hesitant parents. We used multivariable logistic regression to determine the association of demographic characteristics, pregnancy risk, and influenza vaccine receipt with vaccine hesitancy after controlling for variables significant in univariable analyses.

RESULTS

Six hundred ten expectant mothers and 38 expectant fathers completed the Parents Attitudes About Childhood Vaccines survey. Overall, 50 of 610 expectant mothers (8.2%; 95% confidence interval [CI], 6.1%-10.7%) were vaccine-hesitant. Expectant mothers were primarily non-Hispanic white, 30 years old or older, and married. The odds of being vaccine-hesitant were 2.2 times greater (95% CI, 1.2-4.1) among expectant mothers with a college level of education or less compared with those with more than a 4-year degree. The odds of being vaccine-hesitant were 7.4 times greater (95% CI, 3.9-14.0) among expectant mothers who do not receive an annual influenza vaccine compared with those who do.

CONCLUSIONS

Our findings suggest the need to identify and address vaccine hesitancy among expectant parents before birth.

Vaccine Hesitancy and Online Information: The Influence of Digital Networks

Aims. This article analyzes the digital childhood vaccination information network for vaccine-hesitant parents. The goal of this study was to explore the structure and influence of vaccine-hesitant content online by generating a database and network analysis of vaccine-relevant content. Method. We used Media Cloud, a searchable big-data platform of over 550 million stories from 50,000 media sources, for quantitative and qualitative study of an online media sample based on keyword selection. We generated a hyperlink network map and measured indegree centrality of the sources and vaccine sentiment for a random sample of 450 stories. Results. 28,122 publications from 4,817 sources met inclusion criteria. Clustered communities formed based on shared hyperlinks; communities tended to link within, not among, each other. The plurality of information was provaccine (46.44%, 95% confidence interval [39.86%, 53.20%]). The most influential sources were in the health community (National Institutes of Health, Centers for Disease Control and Prevention) or mainstream media ( New York Times); some user-generated sources also had strong influence and were provaccine (Wikipedia). The vaccine-hesitant community rarely interacted with provaccine content and simultaneously used primary provaccine content within vaccine-hesitant narratives. Conclusion. The sentiment of the overall conversation was consistent with scientific evidence. These findings demonstrate an online environment where scientific evidence online drives vaccine information outside of the vaccine-hesitant community but is also prominently used and misused within the robust vaccine-hesitant community. Future communication efforts should take current context into account; more information may not prevent vaccine hesitancy.

Association of moral values with vaccine hesitancy

Clusters of unvaccinated children are particularly susceptible to outbreaks of vaccine-preventable disease ^1,2 . Existing messaging interventions demonstrate short-term success, but some may backfire and worsen vaccine hesitancy ³ . Values-based messages appeal to core morality, which influences the attitudes individuals then have on topics like vaccination ^4-7 . We must understand how underlying morals, not just attitudes, differ by hesitancy type to develop interventions that work with individual values. Here, we show in two correlational studies that harm and fairness foundations are not significantly associated with vaccine hesitancy, but purity and liberty foundations are. We found that medium-hesitancy parents were twice as likely as low-hesitancy parents to highly emphasize purity (adjusted odds ratio: 2.08; 95% confidence interval: 1.27-3.40). High-hesitancy respondents were twice as likely to strongly emphasize purity (adjusted odds ratio: 2.15; 95% confidence interval: 1.39-3.31) and liberty (adjusted odds ratio: 2.19; 95% confidence interval: 1.50-3.21). Our results demonstrate that endorsement of harm and fairness-ideas often emphasized in traditional vaccine-focused messages-are not predictive of vaccine hesitancy. This, combined with significant associations of purity and liberty with hesitancy, indicates a need for inclusion of broader themes in vaccine discussions. These findings have the potential for application to other health decisions and communications as well.

Trends in Personal Belief Exemption Rates Among Alternative Private Schools: Waldorf, Montessori, and Holistic Kindergartens in California, 2000-2014

OBJECTIVES

To evaluate trends in rates of personal belief exemptions (PBEs) to immunization requirements for private kindergartens in California that practice alternative educational methods.

METHODS

We used California Department of Public Health data on kindergarten PBE rates from 2000 to 2014 to compare annual average increases in PBE rates between schools.

RESULTS

Alternative schools had an average PBE rate of 8.7%, compared with 2.1% among public schools. Waldorf schools had the highest average PBE rate of 45.1%, which was 19 times higher than in public schools (incidence rate ratio = 19.1; 95% confidence interval = 16.4, 22.2). Montessori and holistic schools had the highest average annual increases in PBE rates, slightly higher than Waldorf schools (Montessori: 8.8%; holistic: 7.1%; Waldorf: 3.6%).

CONCLUSIONS

Waldorf schools had exceptionally high average PBE rates, and Montessori and holistic schools had higher annual increases in PBE rates. Children in these schools may be at higher risk for spreading vaccine-preventable diseases if trends are not reversed.

A spatiotemporal analysis of non-medical exemptions from vaccination: California schools before and after SB277

Childhood vaccination programs are considered one of the most beneficial public health programs in modern history. In the United States, the increasing use of non-medical exemptions (NMEs) from school entry vaccination requirements has garnered attention and scrutiny in the popular press, academic literature, and policy forums. In 2016, California law SB277 goes into effect, eliminating the NME option for students attending the state's public and private schools. Whereas SB277 is a strong move to increase vaccination coverage within California's schools, the new law contains an important caveat - students already having a valid NME (obtained prior to the 2016 school year) are "grandfathered" in until their next grade checkpoint (seventh grade). Although no new students will enter the California school system with a NME after 2016, the law's grandfather clause will allow NMEs to persist within the state school system until 2022. This analysis demonstrates how the past "build up" of students with pre-SB277 NMEs and the law's grandfather clause will act in combination to affect NME rates across the state after the implementation of SB277. We construct spatially explicit, yearly models of all students (K-12) enrolled in the California school system from 2011 to 2022. Our analysis finds that, although all regions of the state will eventually reach an NME rate of 0% by 2022, SB277's effect will be highly spatially and temporally variable. Some school districts will continue to experience elevated NME rates and increased risk of disease outbreak for years after SB277 is implemented. Our analysis highlights the potential spatially variant consequences of SB277's grandfather clause, providing important information for other states considering similar policy initiatives.

An approach for estimating vaccination coverage for communities using school-level data and population mobility information

Childhood vaccination data are made available at a school level in some U.S. states. These data can be geocoded and may be considered as having a high spatial resolution. However, a school only represents the destination location for the set of students that actually reside and interact within some larger areal region, creating a spatial mismatch. Public school districts are often used to represent these regions, but fail to account for private schools and school of choice programs. We offer a new approach to estimate childhood vaccination coverage rates at a community level by integrating school level data with population commuting information. The resulting mobility-adjusted vaccine coverage estimates resolve the spatial mismatch problem and are more aligned with the geographic scale at which public health policies are implemented. We illustrate the utility of our approach using a case study on diphtheria, tetanus, and pertussis (DTP) vaccination coverage for kindergarten students in California. The modeled community-level DTP coverage estimates yield a statewide coverage of 92.37%, which is highly similar to the 92.44% coverage rate calculated from the original school-level data.

Screening Tool Predicts Future Underimmunization Among a Pediatric Practice in Tennessee

The Parent Attitudes about Childhood Vaccines (PACV) survey for identifying vaccine-hesitant parents was recently validated in Washington State but did not include all recommended childhood vaccines. The current study compares vaccination rates for all recommended childhood vaccines and PACV scores at one pediatric practice in Tennessee. Children were enrolled at the 2-week well visit, and vaccination rates were assessed at 19 months of age. Outcomes at 19 months of age included mean percentage of days underimmunized and up-to-date status (yes/no) compared with PACV scores. The impact of provider on immunization status was assessed. Complete vaccination data were available for 158 children of 183 enrolled (86%). Higher PACV scores were associated with more days underimmunized (P < .001) and being overdue for vaccine doses at 19 months of age (P < .001). No difference was seen between providers and up-to-date status. Our study supports the predictive validity of the PACV for underimmunization.

Affluence as a predictor of vaccine refusal and underimmunization in California private kindergartens

BACKGROUND

Non-medical vaccine exemption rates in California private schools far exceed those of public schools, but little is known about specific factors which may be associated with high exemption rates in private schools.

METHODS

The percent of personal-belief exemptions (PBEs) among California public and private kindergartens were computed for 2000-2001 to 2014-2015 academic years. For the 2014-2015 academic year, a random sample of private schools was selected to investigate associations between kindergarten characteristics (tuition amount, religious affiliation) and vaccine profile (non-medical vaccine exemptions, vaccine coverage).

RESULTS

The proportion of private kindergartens reporting 5% or more children with PBEs increased from 9% (2000-2001) to 34% (2013-2014), followed by a small decrease in 2014-2015 (31%). Overall, 93.7% (565/605) of kindergartens sampled in 2014-2015 had data available. Very high PBE levels (>20%) were seen among secular and non-Catholic, Christian kindergartens but not Roman Catholic, Jewish or Islamic kindergartens. However, the majority of schools at all tuition levels had fewer than 5% of children with a PBE. Kindergartens with an annual tuition of $10,000 or more were over twice as likely to have 20% or more children with PBEs than kindergartens with a lower tuition (p<.01). Additionally, the conditional admission proportions for kindergartens with tuitions of $10,000 or more were 39% compared to 22% for less expensive kindergartens (p<.01). Only about half of all private kindergartens had 95% coverage of the MMR (49%) and pertussis-containing vaccines (51%).

CONCLUSIONS

School-entry vaccination requirements are critical to preventing outbreaks of vaccine preventable diseases in the US. Nonmedical exemptions increased between the 2000-2001 and 2014-2015 academic years and appear to be associated with affluence, raising social justice concerns.

Personal Belief Exemptions to Vaccination in California: A Spatial Analysis

BACKGROUND

School vaccination rates in California have fallen as more parents opt for personal belief exemptions (PBEs) for their children. Our goals were to (1) spatially analyze PBE patterns over time, (2) determine correlates of PBEs, and (3) examine their spatial overlap with personal medical exemptions (PMEs).

METHODS

PBE and PME data for California kindergarten classes from the 2001/2002 to 2013/2014 school years were matched to the locations of schools. Nonspatial clustering algorithms were implemented to group 5147 schools according to their trends in PBE percentages among kindergartners. Cluster assignments were mapped and hotspot analysis was performed to find areas in California where schools sharing trends in PBEs over time were colocated. Schools were further associated both with school-level data on minority enrollment and free and reduced price lunch participation and with charter/private and rural/urban status. Spatial regression was implemented to determine which school-level variables were correlated with PBE rates in the 2013/2014 school year.

RESULTS

Distinct spatial patterns are observed in California when PBE cluster assignments are mapped. Results indicate that schools belonging to the "high PBE" cluster are spatially buffered from those in "low PBE" areas by "medium PBE" schools. Further, PBE rates are positively associated with the percentage of white students, charter status, and private schools.

CONCLUSIONS

Hotspots of high PBE schools are in some cases colocated with schools that have elevated PME rates, prompting concern that herd immunity is diminished for school populations where students have no choice but to remain unvaccinated.

Nonmedical exemptions from school immunization requirements: a systematic review

We summarized studies describing the prevalence of, trends in, and correlates of nonmedical exemptions from school vaccination mandates and the association of these policies with the incidence of vaccine-preventable disease. We searched 4 electronic databases for empirical studies published from 1997 to 2013 to capture exemption dynamics and qualitatively abstracted and synthesized the results. Findings from 42 studies suggest that exemption rates are increasing and occur in clusters; most exemptors questioned vaccine safety, although some exempted out of convenience. Easier state-level exemption procedures increase exemption rates and both individual and community disease risk. State laws influence exemption rates, but policy implementation, exemptors' vaccination status, and underlying mechanisms of geographical clustering need to be examined further to tailor specific interventions.

Perceptions of personal belief vaccine exemption policy: a survey of Arizona vaccine providers

BACKGROUND

As exemptions to school-entry requirements rise, vaccination rates in Arizona school children are approaching levels that may threaten public health. Understanding the interactions physicians have with vaccine-hesitant parents, as well as the opinions physicians hold regarding vaccination, exemption, and exemption policies, are critical to our understanding of, and ability to affect, vaccination exemption rates among children.

METHODS

Survey responses were elicited from practitioners listed in The Arizona Partnership for Immunization and the Arizona Medical Association databases using a multi-pronged recruitment approach. Respondents provided data regarding their practice, comfort with parental refusal of individual vaccines, opinions about the beliefs held by parents that seek exemptions, parent education strategies, issues regarding providing care to unvaccinated children, and potential changes to Arizona policy.

RESULTS

A total of 152 practitioners providing care to a wide geographic and economic population of Arizona responded to the survey. Respondents were generally strong advocates of all immunizations but were more accepting of parents' desires to refuse hepatitis B and rotavirus vaccines. Almost all providers indicated that they see patients whose parents request to refuse or delay from vaccinations at least occasionally (88% and 97%, respectively). Only 37% of respondents indicated that they would be supportive of a policy requiring them to sign off on a parent's decision to refuse vaccination.

CONCLUSIONS

Vaccination providers in Arizona are generally very supportive of childhood immunizations but have varying comfort with exemption from individual vaccines. Responding providers tended to not support a requirement for a physician's signature for vaccine exemptions due to varying concerns regarding the implementation of such a practice.

Epidemiology of vaccine hesitancy in the United States

Vaccines are among the most effective public health interventions against infectious diseases. However, there is evidence in the United States for parents either delaying or refusing recommended childhood vaccination. Exemptions to school immunization laws and use of alternative schedule from those recommended by the Advisory Committee on Immunization Practices and the American Academy of Pediatrics cannot only increase the risk of children contracting vaccine-preventable diseases but also increases the risk of infecting others who are either too young to be vaccinated, cannot be vaccinated for medical reasons or did not develop a sufficient immunological response to the vaccine. Healthcare providers are cited as the most influential source by parents on vaccine decision-making. Vaccine hesitancy needs to be addressed by healthcare providers and the scientific community by listening to the parental concerns and discussing risks associated with either delaying or refusing vaccines.