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Objectives: Vaccine hesitancy is a growing threat to health in the United States. Facing the fourth highest vaccine exemption rate in the United States in 2014, Michigan changed its state Administrative Rules, effective January 1, 2015, requiring parents to attend an in-person vaccine education session at their local health department before obtaining a nonmedical exemption (NME). In this article, we evaluate the longer-term impact of this policy change on the rate, spatial distribution, and sociodemographic predictors of NMEs in Michigan., Methods: Using school-level kindergarten vaccination data from Michigan from 2011 to 2018, we evaluated sociodemographic predictors of NMEs before and after this Administrative Rule change using Bayesian binomial regression. We measured the persistence and location of school district-level geographic clustering using local indicators of spatial association., Results: Immediately after the rule change, rates of NMEs fell by 32%. However, NME rates rebounded in subsequent years, increasing by 26% by 2018, although income disparities in NME rates decreased after the rule change. Philosophical, religious, and medical vaccine exemptions exhibited distinct geographic patterns across the state, which largely persisted after 2015, illustrating that NME clusters remain a concern despite this rule change., Conclusions: Although Michigan's Administrative Rule change caused a short-term decline in NME rates, NME rates have risen dramatically in the following 4 years since the policy was implemented. Michigan's administrative effort to require parental education at the local health department before receiving an exemption did not cause a sustained reduction in the rate or spatial distribution of NMEs., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2021 by the American Academy of Pediatrics.)

The United States experienced historically high numbers of measles cases in 2019, despite achieving national measles vaccination rates above the World Health Organization recommendation of 95% coverage with two doses. Since the COVID-19 pandemic began, resulting in suspension of many clinical preventive services, pediatric vaccination rates in the United States have fallen precipitously, dramatically increasing risk of measles resurgence. Previous research has shown that measles outbreaks in high-coverage contexts are driven by spatial clustering of nonvaccination, which decreases local immunity below the herd immunity threshold. However, little is known about how to best conduct surveillance and target interventions to detect and address these high-risk areas, and most vaccination data are reported at the state-level-a resolution too coarse to detect community-level clustering of nonvaccination characteristic of recent outbreaks. In this paper, we perform a series of computational experiments to assess the impact of clustered nonvaccination on outbreak potential and magnitude of bias in predicting disease risk posed by measuring vaccination rates at coarse spatial scales. We find that, when nonvaccination is locally clustered, reporting aggregate data at the state- or county-level can result in substantial underestimates of outbreak risk. The COVID-19 pandemic has shone a bright light on the weaknesses in US infectious disease surveillance and a broader gap in our understanding of how to best use detailed spatial data to interrupt and control infectious disease transmission. Our research clearly outlines that finer-scale vaccination data should be collected to prevent a return to endemic measles transmission in the United States., Competing Interests: Competing interest statement: P.L.D. has received research funding from Merck for an unrelated project.

Objectives: Kenya has a significant refugee population, including large numbers of Somali migrants. This study examines the vaccination status of Kenyan children and sociodemographic predictors of vaccination, including Somali ethnicity., Methods: Using the 2014 Kenyan Demographic and Health Survey, we calculated the proportion of non-vaccinated, under-vaccinated, and fully vaccinated children, defining full vaccination as one dose Bacille Calmette-Guerin, three doses polio, three doses pentavalent, and one dose measles. We assessed associations among various factors and vaccination status using multinomial logistic regression and explored the effect of Somali ethnicity through interaction analysis., Results: The study sample comprised 4052 children aged 12-23 months, with 79.4% fully, 19.0% under-, and 1.6% non-vaccinated. Among Somalis, 61.9% were fully, 28.7% under-, and 9.4% non-vaccinated. Somalis had significantly greater odds of under- and non-vaccination than the Kikuyu ethnic group. Wealth and birth setting were associated with immunization status for Somalis and non-Somalis., Conclusions: Disparities persist in pediatric vaccinations in Kenya, with Somali children more likely than non-Somalis to be under-vaccinated. Health inequalities among migrants and ethnic communities in Kenya should be addressed.

Background: Timely administration of recommended vaccines requires children to have multiple vaccines co-administered in the first year of life. The objectives of this study were to estimate the proportion of timely vaccinations and the proportion of co-administered vaccines, and to assess the relationship between vaccine co-administration and vaccine timeliness in Kenyan children., Methods: Using the 2014 Kenyan Demographic and Health Survey (DHS), we calculated the proportion of children who received co-administered and timely vaccine doses. Co-administration was defined as doses administered on the same day with dates recorded on vaccination cards. Vaccines were considered timely if given within four days before to four weeks after the recommended interval for administration., Results: 10,385 children aged 1-4 years in the Kenyan 2014 DHS dataset had vaccination cards which comprised the study sample. Analysis revealed wide a range for receipt of timely doses, from 90.2% for OPV0 to 56.0% for Measles. Co-administration of the 6-week dose was associated with 2.81 times higher odds of a timely Penta dose 1 (95% CI: 2.28, 3.46) and birth-dose co-administration was associated with a substantial increase in timely BCG vaccination: AOR 7.43 (95% CI: 6.31, 8.75)., Conclusions: Though vaccine coverage in Kenya was high, timely vaccination was markedly low, with resultant implications for population immunity and potential spread of communicable diseases in unvaccinated infants. Co-administration of vaccines, place of residence, wealth index, and child age were consistently related to the odds of timely vaccine receipt. These relationships reinforce the importance of dedicating resources to programs that educate low socio-economic groups about the importance of vaccine co-administration., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives India has more unvaccinated children than any other country despite provision of free vaccines through the government's Universal Immunization Program. In this study, we calculated the proportion of children aged 12-48 months who were fully vaccinated, under-vaccinated, or who had not received any vaccines. Childhood, household, and sociocultural factors associated with under-vaccination and non-vaccination were evaluated. Methods Using data from India's 4th District-level Health and Facility Survey, 2012-2013 (DLHS-4) and the 2012-2013 Annual Health Survey (AHS), we calculated the proportion of children who were non-vaccinated, under-vaccinated, or fully vaccinated with 1 dose of Bacillus Calmette-Guérin, 3 doses of oral polio vaccine, 3 doses of diphtheria-pertussis-tetanus, and 1 dose of measles-containing vaccine. The odds of full vaccination compared to non-vaccination and under-vaccination relative to various factors was assessed using a multivariable, multinomial logistic regression which accounted for survey design. Results Of 1,929,580 children aged 12-48 months, 59% were fully vaccinated, 34% were under-vaccinated, and 7% were non-vaccinated. Compared to children born in government institutions, children delivered in non-institutional settings with a skilled birth attendant present had higher odds of non-vaccination (OR 1.66) and those without a skilled attendant present had still greater odds of non-vaccination (OR 2.39) and under-vaccination (OR 1.11). Conclusions for Practice India's vaccination rates among children aged 12-48 months remains unacceptably low. The Indian government should encourage institutional delivery or birthing with a skilled attendant to ensure women receive adequate health education through antenatal care that includes the importance of childhood vaccination.

Introduction: Vaccines are vital to reducing childhood mortality, and prevent an estimated 2 to 3 million deaths annually which disproportionately occur in the developing world. Overall vaccine coverage is typically used as a metric to evaluate the adequacy of vaccine program performance, though it does not account for untimely administration, which may unnecessarily prolong children's susceptibility to disease. This study explored a hypothesized positive association between increasing vaccine hesitancy and untimeliness of immunizations administered under the Expanded Program on Immunization (EPI) in Addis Ababa, Ethiopia., Methods: This cross-sectional survey employed a multistage sampling design, randomly selecting one health center within five sub-cities of Addis Ababa. Caregivers of 3 to 12-month-old infants completed a questionnaire on vaccine hesitancy, and their infants' vaccination cards were examined to assess timeliness of received vaccinations., Results: The sample comprised 350 caregivers. Overall, 82.3% of the surveyed children received all recommended vaccines, although only 55.9% of these vaccinations were timely. Few caregivers (3.4%) reported ever hesitating and 3.7% reported ever refusing a vaccine for their child. Vaccine hesitancy significantly increased the odds of untimely vaccination (AOR 1.94, 95% CI: 1.02, 3.71) in the adjusted analysis., Conclusions: This study found high vaccine coverage among a sample of 350 young children in Addis Ababa, though only half received all recommended vaccines on time. High vaccine hesitancy was strongly associated with infants' untimely vaccination, indicating that increased efforts to educate community members and providers about vaccines may have a beneficial impact on vaccine timeliness in Addis Ababa.

IntroductionCOVID-19 vaccines are safe, effective, and widely available, but many adults in the U.S. have not been vaccinated for COVID-19. This study examined the associations between behavioral and social drivers of vaccination with COVID-19 vaccine uptake in the U.S. adults and their prevalence by region.MethodsA nationally representative sample of U.S. adults participated in a cross-sectional telephone survey in August-November 2021; the analysis was conducted in January 2022. Survey questions assessed self-reported COVID-19 vaccine initiation, demographics, and behavioral and social drivers of vaccination.ResultsAmong the 255,763 respondents, 76% received their first dose of COVID-19 vaccine. Vaccine uptake was higher among respondents aged ≥75 years (94%), females (78%), and Asian non-Hispanic people (94%). The drivers of vaccination most strongly associated with uptake included higher anticipated regret from nonvaccination, risk perception, and confidence in vaccine safety and importance, followed by work- or school-related vaccination requirements, social norms, and provider recommendation (all p

IntroductionFocusing on subpopulations that express the intention to receive a COVID-19 vaccination but are unvaccinated may improve the yield of COVID-19 vaccination efforts.MethodsA nationally representative sample of 789,658 U.S. adults aged ≥18 years participated in the National Immunization Survey Adult COVID Module from May 2021 to April 2022. The survey assessed respondents' COVID-19 vaccination status and intent by demographic characteristics (age, urbanicity, educational attainment, region, insurance, income, and race/ethnicity). This study compared composition and within-group estimates of those who responded that they definitely or probably will get vaccinated or are unsure (moveable middle) from the first and last month of data collection.ResultsBecause vaccination uptake increased over the study period, the moveable middle declined among persons aged ≥18 years. Adults aged 18-39 years and suburban residents comprised most of the moveable middle in April 2022. Groups with the largest moveable middles in April 2022 included persons with no insurance (10%), those aged 18-29 years (8%), and those with incomes below poverty (8%), followed by non-Hispanic Native Hawaiian or other Pacific Islander (7%), non-Hispanic multiple or other race (6%), non-Hispanic American Indian or Alaska Native persons (6%), non-Hispanic Black or African American persons (6%), those with below high school education (6%), those with high school education (5%), and those aged 30-39 years (5%).ConclusionsA sizable percentage of adults open to receiving COVID-19 vaccination remain in several demographic groups. Emphasizing engagement of persons who are unvaccinated in some racial/ethnic groups, aged 18-39 years, without health insurance, or with lower income may reach more persons open to vaccination.

Michigan experienced a significant measles outbreak in 2019 amidst rising rates of nonmedical vaccine exemptions (NMEs) and low vaccination coverage compared with the rest of the United States. There is a critical need to better understand the landscape of nonvaccination in Michigan to assess the risk of vaccine-preventable disease outbreaks in the state, yet there is no agreed-upon best practice for characterizing spatial clustering of nonvaccination, and numerous clustering metrics are available in the statistical, geographical, and epidemiologic literature. We used school-level data to characterize the spatiotemporal landscape of vaccine exemptions in Michigan for the period 2008–2018 using Moran's I , the isolation index, the modified aggregation index, and the Theil index at 4 spatial scales. We also used nonvaccination thresholds of 5%, 10%, and 20% to assess the bias incurred when aggregating vaccination data. We found that aggregating school-level data to levels commonly used for public reporting can lead to large biases in identifying the number and location of at-risk students and that different clustering metrics yielded variable interpretations of the nonvaccination landscape in Michigan. This study shows the importance of choosing clustering metrics with their mechanistic interpretations in mind, be it large- or fine-scale heterogeneity or between- and within-group contributions to spatial variation. [ABSTRACT FROM AUTHOR]

• Measles cases among children in Tianjin still occur in those who have been vaccinated. • 29% of measles surveillance system cases with known vaccine history were vaccinated. • In a Case Series from 2011 to 2015, 54% of measles cases had been vaccinated. • Incremental doses of measles vaccine increased the time-to-disease onset. • More research is needed to understand the reasons for vaccine failure. Despite increasing global measles vaccination coverage, progress toward measles elimination has slowed in recent years. In China, children receive a measles-containing vaccine (MCV) at 8 months, 18–24 months, and some urban areas offer a third dose at age 4–6 years. However, substantial measles cases in Tianjin, China, occur among individuals who have received multiple MCV doses. This study describes the vaccination history of measles cases 8 months – 19 years old. Data came from measles cases in Tianjin's reportable disease surveillance system (2009–2013), and from a case control study (2011–2015). Twenty-nine percent of those in the surveillance dataset and 54.4% of those in the case series received at least one dose of MCV. The minimum and median time-to-diagnosis since vaccination revealed an increase in time since vaccination for incremental doses. Considerable measles cases in Tianjin occur in vaccinated children, and further research is needed to understand the reasons for vaccine failure. [ABSTRACT FROM AUTHOR]

By the end of 2021, approximately 15% of U.S. adults remained unvaccinated against COVID-19, and vaccination initiation rates had stagnated. We used unsupervised machine learning (K-means clustering) to identify clusters of unvaccinated respondents based on Behavioral and Social Drivers (BeSD) of COVID-19 vaccination and compared these clusters to vaccinated participants to better understand social/behavioral factors of non-vaccination. The National Immunization Survey Adult COVID Module collects data on U.S. adults from September 26–December 31,2021 (n = 187,756). Among all participants, 51.6% were male, with a mean age of 61 years, and the majority were non-Hispanic White (62.2%), followed by Hispanic (17.2%), Black (11.9%), and others (8.7%). K-means clustering procedure was used to classify unvaccinated participants into three clusters based on 9 survey BeSD items, including items assessing COVID-19 risk perception, social norms, vaccine confidence, and practical issues. Among unvaccinated adults (N = 23,397), 3 clusters were identified: the "Reachable" (23%), "Less reachable" (27%), and the "Least reachable" (50%). The least reachable cluster reported the lowest concern about COVID-19, mask-wearing behavior, perceived vaccine confidence, and were more likely to be male, non-Hispanic White, with no health conditions, from rural counties, have previously had COVID-19, and have not received a COVID-19 vaccine recommendation from a healthcare provider. This study identified, described, and compared the characteristics of the three unvaccinated subgroups. Public health practitioners, healthcare providers and community leaders can use these characteristics to better tailor messaging for each sub-population. Our findings may also help inform decisionmakers exploring possible policy interventions. • We analyzed data from the National Immunization Survey-Adult COVID Module, September–December 2021 (n = 187,756). • Three unvaccinated subgroups were identified by K-means clustering based on social/behavioral drivers of COVID-19 vaccination. • We identified a more reachable unvaccinated subgroup that might be receptive to information promoting vaccination. • COVID-19 vaccination strategies can be tailored based on the characteristics and needs of the targeted sub-populations. [ABSTRACT FROM AUTHOR]

Although global progress in measles control has been realized, achieving elimination has proven difficult in many regions of the world. China has adopted a goal of measles elimination but recent outbreaks predominantly affecting children <8 months who are ineligible for vaccination and incompletely protected by maternal antibodies has impeded progress. We assess the cost-effectiveness of adding an initial measles vaccine dose in China to earlier than the currently recommended 8 months of age. We conducted a cost-utility analysis comparing the costs and health benefits associated with adding a measles vaccine dose to the routine schedule at 4, 5, 6 or 7 months compared to the current recommendation for the first dose at age 8 months. A decision analytic model was developed in Microsoft Excel, including five non-severe and two fatal health outcomes associated with measles infection. Model parameters were informed by the literature and surveillance data. Future costs and health benefits were discounted at 3%. Primary outcomes included costs, Quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) over a lifetime time horizon. Lowering the recommended age for initiating the measles vaccination series to address susceptibility in children <8 months provided incremental health gains compared to minimal costs at the individual-level. The ICER was most favorable ($232.70 per QALY gain) for administering an initial dose at 4 months of age due to fewer incremental program costs when shifting measles administration to an immunization visit already established under the Chinese vaccination program. We found potential beneficial health gains at a minimum cost associated with adding an earlier measles dose <8 months of age in China. Further investigation about disease transmission dynamics is required to more fully assess the tradeoffs of administering measles at a younger age to infants in China. [ABSTRACT FROM AUTHOR]