Vaccination Coverage with Selected Vaccines and Exemption Rates Among Children in Kindergarten - United States, 2019-20 School Year

Are all underimmunized measles clusters equally critical?

This research develops a novel system science approach to examine the potential risk of outbreaks caused by geographical clustering of underimmunized individuals for an infectious disease like measles. We use an activity-based population network model and school immunization records to identify underimmunized clusters of zip codes in the Commonwealth of Virginia. Although Virginia has high vaccine coverage for measles at the state level, finer-scale investigation at the zip code level finds three statistically significant underimmunized clusters. This research examines why some underimmunized geographical clusters are more critical in causing outbreaks and how their criticality changes with a possible drop in overall vaccination coverage. Results show that different clusters can cause vastly different outbreaks in a region, depending on their size, location, immunization rate and network characteristics. Among the three underimmunized clusters, we find one to be critical and the other two to be benign in terms of an outbreak risk. However, when the vaccine coverage among children drops by just 5% (or 0.8% overall in the population), one of the benign clusters becomes highly critical. This work also examines the demographic and network properties of these clusters to identify factors that are responsible for affecting the criticality of the clusters. Although this work focuses on measles, the methodology is generic and can be applied to study other infectious diseases.

Are all underimmunized measles clusters equally critical?

Disruptions in routine immunizations due to the COVID-19 pandemic have been a cause of significant concern for health organizations worldwide. This research develops a system science approach to examine the potential risk of geographical clustering of underimmunized individuals for an infectious disease like measles. We use an activity-based population network model and school immunization records to identify underimmunized clusters of zip codes in the Commonwealth of Virginia. Although Virginia has high vaccine coverage at the state level for measles, finer-scale investigation at the zip code level finds three statistically significant underimmunized clusters. To estimate the criticality of these clusters, a stochastic agent-based network epidemic model is used. Results show that different clusters can cause vastly different outbreaks in the region, depending on their size, location, and network characteristics. This research aims to understand why some underimmunized geographical clusters do not cause a large outbreak while others do. A detailed network analysis shows that it is not the average degree of the cluster or the percentage of underimmunized individuals in the cluster but the average eigenvector centrality of the cluster that is important in determining its potential risk.

Evaluating the Accuracy of the Annual Statewide Kindergarten Vaccination Survey Submitted to Public Health Authorities by School Systems, Oklahoma, 2018

Recent trends in vaccine hesitancy have brought to light the importance of using accurate school vaccination data. This study evaluated the accuracy of a pilot statewide kindergarten vaccination survey in Oklahoma. School vaccination and exemption data were collected from November 2017 to April 2018 via the Research Electronic Data Capture system. A multivariable linear regression model was used to evaluate the relationship between students who are up to date for all vaccines comparing school reported and Oklahoma State Department of Health-validated data. Adjusted vaccination data were overestimated by 1.0% among public schools and 3.3% among private schools. These results were validated by a random audit of participating schools finding the school-reported vaccination data to be overestimated by 0.6% compared to true student immunization records on file. Our analysis indicates that school-reported vaccination data are sufficiently valid. Immunization record audits provide confidence in available data, which drives evidence-based decision-making.

Value of the Immunization Program for Children in the 2017 US Birth Cohort

BACKGROUND AND OBJECTIVES

We evaluated the economic impact of routine childhood immunization in the United States, reflecting updated vaccine recommendations and recent data on epidemiology and coverage rates.

METHODS

An economic model followed the 2017 US birth cohort from birth through death; impact was modeled via a decision tree for each of the vaccines recommended for children by the Advisory Committee on Immunization Practices as of 2017 (with annual influenza vaccine considered in scenario analysis). Using information on historic prevaccine and vaccine-era incidence and disease costs, we calculated disease cases, deaths, disease-related healthcare costs, and productivity losses without and with vaccination, as well as vaccination program costs. We estimated cases and deaths averted because of vaccination, life-years and quality-adjusted life-years gained because of vaccination, incremental costs (2019 US dollars), and the overall benefit-cost ratio (BCR) of routine childhood immunization from the societal and healthcare payer perspectives.

RESULTS

Over the cohort's lifetime, routine childhood immunization prevented over 17 million cases of disease and 31 000 deaths; 853 000 life years and 892 000 quality-adjusted life-years were gained. Estimated vaccination costs ($8.5 billion) were fully offset by the $63.6 billion disease-related averted costs. Routine childhood immunization was associated with $55.1 billion (BCR of 7.5) and $13.7 billion (BCR of 2.8) in averted costs from a societal and healthcare payer perspective, respectively.

CONCLUSIONS

In addition to preventing unnecessary morbidity and mortality, routine childhood immunization is cost-saving. Continued maintenance of high vaccination coverage is necessary to ensure sustained clinical and economic benefits of the vaccination program.

COVID-19 Vaccine Acceptance Among US Parents: A Nationally Representative Survey

BACKGROUND

Little was known about US parental attitudes, beliefs, and intentions surrounding coronavirus disease 2019 (COVID-19) vaccines for children before their introduction.

METHODS

An online cross-sectional nationally representative survey of US parents/guardians of children < 18 years old via Ipsos KnowledgePanel, fielded from October 26, 2021 to November 30, 2021.

RESULTS

Response rate was 64.2% (3230/5034). For children ages 0-4 years, 51.5% of parents were likely to have their children vaccinated, and for ages 5-11 and 12-17, 54.0% and 69.7% of parents, respectively, reported they were likely to vaccinate or had already vaccinated their children. Among respondents with unvaccinated children, 25.2% (ages 0-4) and 22.0% (ages 5-11) reported they would seek COVID-19 vaccination for their children as soon as authorization occurred. Factors associated with willingness to have children receive a COVID-19 vaccine were: belief in benefits of COVID-19 vaccination (odds ratio [OR] = 6.44, 5.68, 4.57 in ages 0-4, 5-11, and 12-17 respectively), acceptance of routine childhood vaccines (OR = 6.42, 5.48, 1.76), parental COVID-19 vaccination (OR = 1.85, 3.70, 6.16), perceptions that pediatric COVID-19 is severe (OR = 1.89, 1.72, 1.35), Hispanic ethnicity (OR = 2.07, 2.29, 2.60), influenza vaccine acceptance (OR = 1.07, 0.88, 1.62), presence of children of another age group in the household (OR = 0.71, 0.71, 0.65), and attitudinal barriers to COVID-19 vaccination (OR = 0.30, 0.26, 0.49).

CONCLUSIONS

Belief in the benefits of COVID-19 vaccination and acceptance of routine childhood vaccines are the strongest predictors of intention to vaccinate children. Further research is needed to track how parental attitudes change as more data about pediatric COVID-19 vaccines become available and how intentions translate into pediatric vaccine uptake.

Acceptability of COVID-19 vaccine mandates among New York City parents, November 2021

School-based vaccine mandates improve vaccination coverage in children. We conducted a cross-sectional survey of parents in New York City (NYC) in November 2021 to measure acceptability of COVID-19 vaccine mandates for students, and for teachers and school staff. Random address-based sampling was used to recruit parents of children 5-11 years of age. Among 2,506 parents surveyed, 44.3% supported school-based vaccine mandates for students and 69.1% supported mandates for teachers and school staff. Asian parents, male parents, those with higher income, college education, those voting for the 2021 Democratic mayoral candidate and parents from Manhattan were most likely to support vaccine mandates for students. Among all parents, 25.1% said they would not vaccinate their child if required. Our data show only modest support for school-based COVID-19 vaccine mandates for children despite their importance in improving vaccination coverage.

Towards Eliminating Nonmedical Vaccination Exemptions Among School-Age Children

The increase in childhood vaccine hesitancy and corresponding use of nonmedical exemptions to abstain from vaccination has deleteriously impacted the public’s health. This has many in the field calling for widespread elimination of nonmedical school-entry exemptions, as has been done in six states to date: West Virginia, Mississippi, California, New York, Maine, and Connecticut. By eliminating nonmedical exemptions, vaccination rates can be improved, with the corresponding decline in vaccine-preventable disease incidence. Yet the path towards widespread adoption of these policies presents legislative and judicial implications which evolve with the changing political landscape. In this this article, we discuss legislative actions concerning the expansion of exemptions, whether the widespread elimination of nonmedical exemptions would be effective from a practical and legal end, and how the COVID-19 pandemic has influenced such legislation, with specific focus on Delaware.

Association of the COVID-19 Pandemic With Routine Childhood Vaccination Rates and Proportion Up to Date With Vaccinations Across 8 US Health Systems in the Vaccine Safety Datalink

IMPORTANCE

The COVID-19 pandemic has affected routine vaccine delivery in the US and globally. The magnitude of these disruptions and their association with childhood vaccination coverage are unclear.

OBJECTIVES

To compare trends in pediatric vaccination before and during the pandemic and to evaluate the proportion of children up to date (UTD) with vaccinations by age, race, and ethnicity.

DESIGN, SETTING, AND PARTICIPANTS

This surveillance study used a prepandemic-postpandemic control design with data from 8 health systems in California, Oregon, Washington, Colorado, Minnesota, and Wisconsin in the Vaccine Safety Datalink. Children from age groups younger than 24 months and 4 to 6, 11 to 13, and 16 to 18 years were included if they had at least 1 week of health system enrollment from January 5, 2020, through October 3, 2020, over periods before the US COVID-19 pandemic (January 5, 2020, through March 14, 2020), during age-limited preventive care (March 15, 2020, through May 16, 2020), and during expanded primary care (May 17, 2020, through October 3, 2020). These individuals were compared with those enrolled during analogous weeks in 2019.

EXPOSURES

This study evaluated UTD status among children reaching specific ages in February, May, and September 2020, compared with those reaching these ages in 2019.

MAIN OUTCOMES AND MEASURES

Weekly vaccination rates for routine age-specific vaccines and the proportion of children UTD for all age-specific recommended vaccines.

RESULTS

Of 1 399 708 children in 2019 and 1 402 227 in 2020, 1 371 718 were female (49.0%) and 1 429 979 were male (51.0%); 334 216 Asian individuals (11.9%), 900 226 were Hispanic individuals (32.1%), and 201 619 non-Hispanic Black individuals (7.2%). Compared with the prepandemic period and 2019, the age-limited preventive care period was associated with lower weekly vaccination rates, with ratios of rate ratios of 0.82 (95% CI, 0.80-0.85) among those younger than 24 months, 0.18 (95% CI, 0.16-0.20) among those aged 4 to 6 years, 0.16 (95% CI, 0.14-0.17) among those aged 11 to 13 years, and 0.10 (95% CI, 0.08-0.13) among those aged 16 to 18 years. Vaccination rates during expanded primary care remained lower for most ages (ratios of rate ratios: <24 months, 0.96 [95% CI, 0.93-0.98]; 11-13 years, 0.81 [95% CI, 0.76-0.86]; 16-18 years, 0.57 [95% CI, 0.51-0.63]). In September 2020, 74% (95% CI, 73%-76%) of infants aged 7 months and 57% (95% CI, 56%-58%) of infants aged 18 months were UTD vs 81% (95% CI, 80%-82%) and 61% (95% CI, 60%-62%), respectively, in September 2019. The proportion UTD was lowest in non-Hispanic Black children across most age groups, both during and prior to the COVID-19 pandemic (eg, in May 2019, 70% [95% CI, 64%-75%] of non-Hispanic Black infants aged 7 months were UTD vs 82% [95% CI, 81%-83%] in all infants aged 7 months combined).

CONCLUSIONS AND RELEVANCE

As of September 2020, childhood vaccination rates and the proportion who were UTD remained lower than 2019 levels. Interventions are needed to promote catch-up vaccination, particularly in populations at risk for underimmunization.

US Primary Care Providers' Experiences and Practices Related to Routine Pediatric Vaccination During the COVID-19 Pandemic

OBJECTIVE

To describe, among pediatricians (Peds) and family physicians (FPs), 1) changes made to routine childhood vaccination delivery as a result of the pandemic, and 2) perceived barriers to delivering vaccinations from March 2020 through the time of the survey.

METHODS

A nationally representative survey among Peds and FPs was administered by mail or Internet in October-December 2020.

RESULTS

Response rate was 64% (579/909). For children aged 0 to 2 years, among those who vaccinated that age group prepandemic (Peds n = 265, FPs n = 222), 5% of Peds and 15% of FPs reported they had stopped vaccinating these children at any time. For children aged 4 to 6 years (Peds n=264, FPs n = 229), 19% of Peds and 17% of FPs reported they had stopped vaccinating at any time. For children aged 11-18 years (Peds n = 265, FPs n = 251), 24% of Peds and 19% of FPs reported they had stopped vaccinating at any time. Nearly all reported returning to prepandemic vaccination services at the time of the survey. Factors most frequently reported as major/moderate barriers to providing vaccinations included fewer in-person visits because patients/parents were concerned about risk of SARS-CoV-2 infection (Peds, 52%; FPs, 54%), fewer in-person visits for sports clearance (Peds, 39%; FPs, 44%), and fewer back-to-school in-person visits because some children were in virtual learning (Peds, 25%; FPs, 33%).

CONCLUSIONS

Although some physicians reported interrupting vaccination services at some point during the pandemic, the majority reported continuing to provide vaccinations throughout, with essentially all returning to prepandemic vaccination services by end of 2020.

Syndromic surveillance of vaccine-associated adverse events in U.S. emergency departments

The Centers for Disease Control and Prevention explored use of emergency department (ED) visit data, during 2018-2020, from the National Syndromic Surveillance Program to monitor vaccine-associated adverse events (VAE) among all age groups. A combination of chief complaint terms and administrative diagnosis codes were used to detect VAE-related ED visits. Postvaccination fever was among the top 10 most frequently noted diagnoses. VAE annual trends demonstrated seasonality; visits trended upward starting in September of each year, coinciding with the administration of seasonal influenza vaccines. The 2020 VAE-related visit trend declined below the 2018 and 2019 baselines during March 22-September 5, 2020, before returning to the seasonal pattern. VAE-related visits declined in children aged 3-18 years in 2020 compared with 2018-2019, especially in the back-to-school months. These findings demonstrate that syndromic surveillance can complement traditional VAE reporting systems without an additional demand on data collection resources.

Addressing Parental Vaccine Hesitancy and Other Barriers to Childhood/Adolescent Vaccination Uptake During the Coronavirus (COVID-19) Pandemic

Routine childhood immunizations are proven to be one of the most effective public health interventions at controlling numerous deadly diseases. Therefore, the CDC recommends routine immunizations for children and adolescent populations against vaccine-preventable diseases e.g., tetanus, pertussis, diphtheria, etc. This current review sought to examine barriers to pediatric vaccine uptake behaviors during the COVID-19 pandemic. We also explored the implications for parental vaccine hesitancy/delay during an ongoing health crisis and proposed recommendations for increasing vaccine confidence and compliance. Our review determined that the receipt for vaccinations steadily improved in the last decade for both the United States and Tennessee. However, this incremental progress has been forestalled by the COVID-19 pandemic and other barriers i.e. parental vaccine hesitancy, social determinants of health (SDoH) inequalities, etc. which further exacerbate vaccination disparities. Moreover, non-compliance to routine vaccinations could cause an outbreak of diseases, thereby, worsening the ongoing health crisis and already strained health care system. Healthcare providers are uniquely positioned to offer effective recommendations with presumptive languaging to increase vaccination rates, as well as, address parental vaccine hesitancy. Best practices that incorporate healthcare providers' quality improvement coaching, vaccination reminder recall systems, adherence to standardized safety protocols (physical distancing, hand hygiene practices, etc.), as well as, offer telehealth and outdoor/drive-through/curbside vaccination services, etc. are warranted. Additionally, a concerted effort should be made to utilize public health surveillance systems to collect, analyze, and interpret data, thereby, ensuring the dissemination of timely, accurate health information for effective health policy decision-making e.g., vaccine distribution, etc.