Frequency of alternative immunization schedule use in a metropolitan area

Community Engagement in Vaccination Promotion: Systematic Review and Meta-Analysis

BACKGROUND

Community engagement plays a vital role in global immunization strategies, offering the potential to overcome vaccination hesitancy and enhance vaccination confidence. Although there is significant backing for community engagement in health promotion, the evidence supporting its effectiveness in vaccination promotion is fragmented and of uncertain quality.

OBJECTIVE

This review aims to systematically examine the effectiveness of different contents and extent of community engagement for promoting vaccination rates.

METHODS

This study was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A comprehensive and exhaustive literature search was performed in 4 English databases (PubMed, Embase, Web of Science, and Cochrane Library) and 2 Chinese databases (CNKI and Wan Fang) to identify all possible articles. Original research articles applying an experimental study design that investigated the effectiveness of community engagement in vaccination promotion were eligible for inclusion. Two reviewers independently performed the literature search, study selection, quality assessment, and data extraction. Discrepancies were resolved through discussion, with the arbitration of a third reviewer where necessary.

RESULTS

A total of 20 articles out of 11,404 records from 2006 to 2021 were retrieved. The studies used various designs: 12 applied single-group pre-post study designs, 5 were cluster randomized controlled trials (RCTs), and 3 were non-RCTs. These studies targeted multiple vaccines, with 8 focusing on children's immunization, 8 on human papillomavirus vaccine, 3 on hepatitis B virus vaccine, and 1 on COVID-19 vaccine. The meta-analysis revealed significant increases in vaccination rates both in pre-post comparison (rate difference [RD] 0.34, 95% CI 0.21-0.47, I2=99.9%, P<.001) and between-group comparison (RD 0.18, 95% CI 0.07-0.29, I2=98.4%, P<.001). The meta-analysis revealed that participant recruitment had the largest effect size (RD 0.51, 95% CI 0.36-0.67, I2=99.9%, P<.001), followed by intervention development (RD 0.36, 95% CI 0.23-0.50, I2=100.0%, P<.001), intervention implementation (RD 0.35, 95% CI 0.22-0.47, I2=99.8%, P<.001), and data collection (RD 0.34, 95% CI 0.19-0.50, I2=99.8%, P<.001). The meta-analysis indicated that high community engagement extent yielded the largest effect size (RD 0.49, 95% CI 0.17-0.82, I2=100.0%, P<.001), followed by moderate community engagement extent (RD 0.45, 95% CI 0.33-0.58, I2=99.6%, P<.001) and low community engagement extent (RD 0.15, 95% CI 0.05-0.25, I2=99.2%, P<.001). The meta-analysis revealed that "health service support" demonstrated the largest effect sizes (RD 0.45, 95% CI 0.25-0.65, I2=99.9%, P<.001), followed by "health education and discussion" (RD 0.39, 95% CI 0.20-0.58, I2=99.7%, P<.001), "follow-up and reminder" (RD 0.33, 95% CI 0.23-0.42, I2=99.3%, P<.001), and "social marketing campaigns and community mobilization" (RD 0.24, 95% CI 0.06-0.41, I2=99.9%, P<.001).

CONCLUSIONS

The results of this meta-analysis supported the effectiveness of community engagement in vaccination promotion with variations in terms of engagement contents and extent. Community engagement required a "fit-for-purpose" approach rather than a "one-size-fits-all" approach to maximize the effectiveness of vaccine promotion.

TRIAL REGISTRATION

PROSPERO CRD42022339081; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=339081.

Identification of Spatial Clusters of Undervaccination Patterns Among Children Aged <24 Months Using Immunization Information System Data, Montana, 2015-2019

OBJECTIVE

Spatial clustering of undervaccination leads to increased risk of vaccine-preventable diseases. We identified spatial clustering of undervaccination patterns among children aged <24 months in Montana.

METHODS

We used Montana's immunization information system data to analyze deidentified vaccination records of children aged <24 months born from January 2015 through November 2017. We measured 3 outcomes that were not mutually exclusive: not completing the combined 7-vaccine series by age 24 months, having an undervaccination pattern indicative of parental hesitancy, and having an undervaccination pattern indicative of structural barriers to timely vaccination. Using geomasked residential addresses, we conducted separate Bernoulli spatial scans with a randomization P < .01 to identify spatial clusters consisting of ≥100 children for each outcome and calculated the relative risk of having the undervaccination pattern inside versus outside the cluster.

RESULTS

Of 31 201 children aged <24 months included in our study, 11 712 (37.5%) had not completed the combined 7-vaccine series by age 24 months, and we identified 5 spatial clusters of this outcome across Montana. We identified 4 clusters of undervaccination patterns indicative of parental vaccine hesitancy, all in western Montana. The cluster with the largest relative risk (2.3) had a radius of 23.7 kilometers (n = 762 children, P < .001). We also identified 4 clusters of undervaccination patterns indicative of structural barriers, with 3 of the largest clusters in eastern Montana.

CONCLUSION

In Montana, different strategies to increase routine and timely childhood vaccination are needed in distinct areas of this large and predominantly rural state. Immunization information system data can pinpoint areas where interventions to increase vaccination uptake are needed.

Strategies for Improving Vaccine Communication and Uptake

Vaccines have led to a significant decrease in rates of vaccine-preventable diseases and have made a significant impact on the health of children. However, some parents express concerns about vaccine safety and the necessity of vaccines. The concerns of parents range from hesitancy about some immunizations to refusal of all vaccines. This clinical report provides information about the scope and impact of the problem, the facts surrounding common vaccination concerns, and the latest evidence regarding effective communication techniques for the vaccine conversation. After reading this clinical report, readers can expect to: Understand concepts and underlying determinants of vaccine uptake and vaccine hesitancy.Understand the relationship between vaccine hesitancy and costs of preventable medical care.Recognize and address specific concerns (eg, vaccine safety) with caregivers when hesitancy is present.

National trends in patterns of under-vaccination in early childhood: National Immunization Survey-Child, United States, 2011-2021

BACKGROUND

The study's objective was to examine national trends in patterns of under-vaccination in the United States.

RESEARCH DESIGN AND METHODS

The National Immunization Survey-Child (NIS-Child) is an annual cross-sectional survey that collects provider-verified vaccination records from a large national probability sample of children. Records from the 2011-2021 NIS-Child were used to assess receipt of the combined 7-vaccine series by age 24 months. Based on prior work, patterns indicative of hesitancy included zero vaccines, not starting ≥1 series, and consistent vaccine-limiting. Patterns indicative of practical issues included starting all series but missing doses. Up-to-date (UTD) was defined as receiving all doses in the combined 7-vaccine series.

RESULTS

The study population comprised 127,257 children. Over the observation period, patterns indicative of hesitancy significantly decreased (p-trend < 0.0001), patterns indicative of practical issues significantly decreased (p-trend < 0.0001), and UTD significantly increased (p-trend < 0.0001). In 2021, the weighted percentage in each category was as follows: probable hesitancy 6.3% (95% confidence interval [CI] 5.4%, 7.2%), probable practical issues 26.0% (95% CI 24.4%, 27.6%), and UTD 67.7% (95% CI 66.0%, 69.4%).

CONCLUSION

Over an 11-year period, vaccination coverage in the United States for the combined 7-vaccine series has improved, with patterns suggestive of practical issues or hesitancy declining.

Estimating Vaccine Hesitancy in Colorado by Using Immunization Information System Data

OBJECTIVES

Vaccine hesitancy is a complex issue that threatens global health. We used data from the Colorado Immunization Information System (CIIS) to quantify vaccine hesitancy.

METHODS

We examined immunization records from CIIS for patients age 2 up to 9 months to estimate vaccine hesitancy by tabulating the number of doses received per visit and comparing it with the number of expected doses based on recommendations of the Advisory Committee on Immunization Practices. We calculated the percentage of patients in each vaccine hesitancy group who were up to date on the 7-antigen series by age 35 months. We examined the distribution of vaccine-hesitant populations among vaccination providers who report to CIIS to estimate the difference in vaccine-hesitant patient populations among vaccination providers in Colorado.

RESULTS

Of 201 450 patients, 5147 (2.6%) consistently limited the number of shots received at each visit as compared with recommendations from the Advisory Committee on Immunization Practices; 166 927 (82.9%) patients did not limit the number of shots received; 5693 (2.8%) limited the number of shots received at >1 visit but not all visits; and 23 683 (11.8%) limited the number of shots received at only 1 visit. We found differences in vaccine hesitancy distributions among certain Colorado vaccination providers.

CONCLUSIONS

Immunization information system data, although sometimes incomplete, offer an opportunity to investigate state-level vaccine hesitancy. Areas of future research include performing similar analyses over time and determining geographic and socioeconomic factors that contribute to vaccine hesitancy.

Geographic proximity to immunization providers and vaccine series completion among children ages 0-24 months

OBJECTIVES

In the U.S., vaccination coverage is lower in rural versus urban areas. Spatial accessibility to immunization services has been a suspected risk factor for undervaccination in rural children. Our objective was to identify whether geographic factors, including driving distance to immunization providers, were associated with completion of recommended childhood vaccinations.

METHODS

We analyzed records from Montana's immunization information system for children born 2015-2017. Using geolocated address data, we calculated distance in road miles from children's residences to the nearest immunization provider. A multivariable log-linked binomial mixed model was used to identify factors associated with completion of the combined 7-vaccine series by age 24 months.

RESULTS

Among 26,085 children, 16,503 (63.3%) completed the combined 7-vaccine series by age 24 months. Distance to the nearest immunization provider ranged from 0 to 81.0 miles (median = 1.7; IQR = 3.2), with the majority (92.1%) of children living within 10 miles of a provider. Long distances (>10 miles) to providers had modest associations with not completing the combined 7-vaccine series (adjusted prevalence ratio [aPR]: 0.97, 95% confidence interval [CI]: 0.96-0.99). After adjustment for other factors, children living in rural areas (measured by rural-urban commuting area) were significantly less likely to have completed the combined 7-vaccine series than children in metropolitan areas (aPR: 0.88, 95% CI: 0.85-0.92).

CONCLUSIONS

Long travel distances do not appear to be a major barrier to childhood vaccination in Montana. Other challenges, including limited resources for clinic-based strategies to promote timely vaccination and parental vaccine hesitancy, may have greater influence on rural childhood vaccination.

Beyond Vaccination Coverage: Population-Based Measurement of Early Childhood Immunization Schedule Adherence

The immunization schedule recommended by the U.S. Advisory Committee on Immunization Practices (ACIP) provides a structure for how 10 different vaccine series should be administered to children in the first 18 months of life. Progress toward US early childhood immunization goals has largely focused on measuring vaccination coverage at age 24 months. However, standard vaccination coverage measures do not reflect whether children received vaccine doses by recommended ages, or whether vaccines were given concomitantly, per the schedule. In this paper, we describe innovations in population-level measurement of immunization schedule adherence through quantifying vaccination timeliness and undervaccination patterns. Measuring vaccination timeliness involves comparing when children received vaccine doses relative to ACIP age recommendations. To assess undervaccination patterns, children's vaccination histories are analyzed to determine whether they were vaccinated consistent with the ACIP schedule. Some patterns, such as spreading out vaccines across visits, are indicative of parental hesitancy. Other patterns, such as starting all recommended series but missing doses, are largely indicative of other immunization services delivery challenges. Since 2003, at least 12 studies have used National Immunization Survey-Child, immunization information system, or integrated health plan data to measure vaccination timeliness or undervaccination patterns at national or state levels. Moving forward, these novel measures can be leveraged for population-based surveillance of vaccine confidence, and for distinguishing undervaccination due to parental vaccine hesitancy from undervaccination due to other causes. Broader adoption of these measures can facilitate identification of targeted strategies for improving timely and routine early childhood vaccination uptake across the United States.

Characteristics of Oklahoma Pediatricians Who Dismiss Families for Refusing Vaccines

Vaccine refusal is increasing. Objectives were to assess frequency of declining or dismissing patients who refuse vaccines, which vaccine(s) prompt pediatricians to decline/dismiss patients, and demographics of pediatricians who decline/dismiss patients. Active members of the Oklahoma American Academy of Pediatricians (AAP) were surveyed. Chi-square tests with non-overlapping 95% confidence intervals compared proportions of providers across various metrics. In all, 47% (48/103) versus 35% (34/98) reported declining versus dismissing patients for refusing vaccines, respectively. Pediatricians were unlikely to decline/dismiss patients if they refused influenza, human papilloma virus (HPV), or MenB vaccines. Pediatricians with more years in practice were less likely to decline 15% (9/62) versus 44% (16/36), P = 0.002 and dismiss 8% (5/62) versus 33% (12/36), P = 0.002 patients. Rural pediatricians were less likely than urban to decline 12% (2/17) versus 29% (26/89), P = NS and dismiss patients 0% (0/17) versus 21% (19/89), P = 0.04. Dismissing/declining patients for vaccine refusal is more common among Oklahoma pediatricians than nationally reported. Patterns differ by practice setting, years in practice, and specific vaccine refused.

Evaluating vaccination coverage and timeliness in American Indian/Alaska Native and non-Hispanic White children using state immunization information system data, 2015-2017

Comprehensive estimates of vaccination coverage and timeliness of vaccine receipt among American Indian/Alaska Native (AI/AN) children in the United States are lacking. This study’s objectives were to quantify vaccination coverage and timeliness, as well as the proportion of children with specific undervaccination patterns, among AI/AN and non-Hispanic White (NHW) children ages 0–24 months in Montana, a large and primarily rural U.S. state. Data from Montana’s immunization information system (IIS) for children born 2015–2017 were used to calculate days undervaccinated for all doses of seven recommended vaccine series. After stratifying by race/ethnicity, up-to-date coverage at key milestone ages and the proportion of children demonstrating specific patterns of undervaccination were reported. Among n = 3,630 AI/AN children, only 23.1% received all recommended vaccine doses on-time (i.e., zero days undervaccinated), compared to 40.4% of n = 18,022 NHW children (chi-square p < 0.001). A greater proportion of AI/AN children were delayed at each milestone age, resulting in lower overall combined 7-vaccine series completion, by age 24 months (AI/AN: 56.6%, NHW: 64.3%, chi-square p < 0.001). As compared with NHW children, a higher proportion of AI/AN children had undervaccination patterns suggestive of structural barriers to accessing immunization services and delayed starts to vaccination. More than three out of four AI/AN children experienced delays in vaccination or were missing doses needed to complete recommended vaccine series. Interventions to ensure on-time initiation of vaccine series at age 2 months, as well initiatives to encourage completion of multi-dose vaccine series, are needed to reduce immunization disparities and increase vaccination coverage among AI/AN children in Montana.

Barriers to and facilitators of early childhood immunization in rural areas of the United States: A systematic review of the literature

Early childhood vaccination rates are lower in rural areas of the U.S. compared with suburban and urban areas. Our aim was to identify barriers to and facilitators of early childhood immunization in rural U.S. communities. We completed a systematic review of original research conducted in the U.S. between January 1, 2000-July 25, 2021. We searched PubMed, Cumulative Index for Nursing and Allied Health Literature, and Web of Science. We included studies that examined barriers to and facilitators of routine immunizations in children <36 months old in rural areas. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, we reported studies' methodologies and targeted populations, definitions of rurality, and common themes across studies that reflected barriers to or facilitators of vaccination. Ultimately, 17 papers met inclusion criteria for review. The majority of studies (10/17) were conducted within one U.S. state, and the same number (10/17) were conducted prior to 2005. Facilitators of vaccine uptake in rural communities identified across studies included reminder/recall systems and parents' relationships with providers. Parental hesitancy, negative clinic experiences, referrals outside of primary care settings, and distance to providers were identified as barriers to vaccination in rural settings. This review revealed a limited scope of evidence on barriers to and facilitators of early childhood immunization in rural communities. More investigations of the causes of low vaccine coverage and the effectiveness of interventions for increasing vaccine uptake are urgently needed in rural pediatric populations to address persistent rural-urban immunization disparities.

The Social Bifurcation of Reality: Symmetrical Construction of Knowledge in Science-Trusting and Science-Distrusting Discourses

This article proposes a conceptual framework to study the social bifurcation of reality in polarized science-trusting and science-distrusting lay worldviews, by analyzing and integrating five concepts: science work, number work, emotion work, time work, and boundary work. Despite the epistemological asymmetry between accounts relying on mainstream science and science-distrusting or denialist ones, there are symmetrical social processes contributing to the construction of lay discourses. Through conceptual analysis, we synthesize an alternative to the deficit model of contrarian discourses, replacing the model of social actors as "defective scientists" with a focus on their culturally competent agency. The proposed framework is useful for observing the parallel construction of polarized realities in interaction and their ongoing articulation through hinge objects, such as vaccines, seatbelts, guns, or sanitary masks in the Covid-19 context. We illustrate the framework through a comparative approach, presenting arguments and memes from contemporary online media in two controversies: namely, vaccine-trusting versus vaccine-distrusting views and Covid-convinced versus Covid-suspicious discourses.

Vaccine timeliness and prevalence of undervaccination patterns in children ages 0-19 months, U.S., National Immunization Survey-Child 2017

OBJECTIVES

Typically, early childhood vaccination coverage in the U.S. is measured as the proportion of children by age 24 months who completed recommended vaccine series. However, these measures do not reflect whether vaccine doses were received at the ages recommended by the U.S. Advisory Committee on Immunization Practices, or whether children received vaccines concomitantly, per the ACIP recommended schedule. This study's objective was to quantify vaccine timeliness and prevalence of specific patterns of undervaccination in U.S. children ages 0-19 months.

METHODS

Using 2017 National Immunization Survey-Child data, we calculated days undervaccinated for the combined 7-vaccine series and distinguished undervaccination patterns indicative of parental vaccine hesitancy, such as spreading out vaccines across visits ("shot-limiting") or starting some but not all recommended vaccine series ("selective vaccination"), from other non-hesitancy patterns, such as missing final vaccine doses or receiving all doses, with some or all late. We measured associations between demographic, socioeconomic and other characteristics with undervaccination patterns using multivariable log-linked binomial regression. Analyses accounted for the complex survey design.

RESULTS

Among n = 15,333 U.S. children, only 41.2% received all recommended vaccine doses on-time by age 19 months. Approximately 20.9% of children had an undervaccination pattern suggestive of parental vaccine hesitancy, and 36.2% had other undervaccination non-hesitancy patterns. Uninsured children and those with lower levels of maternal education were more likely to exhibit undervaccination patterns suggestive of parental hesitancy. Lower levels of maternal education were also associated with other non-hesitancy undervaccination patterns.

CONCLUSIONS

More than half of children in the U.S. are undervaccinated at some point by 19 months of age. Ongoing assessment of vaccine timeliness and immunization schedule adherence could facilitate timely and targeted public health interventions in populations with high levels of undervaccination.

Parental childhood vaccine hesitancy and predicting uptake of vaccinations: a systematic review

Aim:

This review aims are to (1) identify relevant quantitative research on parental childhood vaccine hesitancy with vaccine uptake and vaccination intention being relevant outcomes and (2) map the gaps in knowledge on vaccine hesitancy to develop suggestions for further research and to guide interventions in this field.

Background:

Vaccine hesitancy recognises a continuum between vaccine acceptance and vaccine refusal, de-polarising past anti-vaccine, and pro-vaccine categorisations of individuals and groups. Vaccine hesitancy poses a serious challenge to international efforts to lessen the burden of vaccine-preventable diseases. Potential vaccination barriers must be identified to inform initiatives aimed at increasing vaccine awareness, acceptance, and uptake.

Methods:

Five databases were searched for peer-reviewed articles published between 1998 and 2020 in the fields of medicine, nursing, public health, biological sciences, and social sciences. Across these datasets, a comprehensive search technique was used to identify multiple variables of public trust, confidence, and hesitancy about vaccines. Using PRISMA guidelines, 34 papers were included so long as they focused on childhood immunisations, employed multivariate analysis, and were published during the time frame. Significant challenges to vaccine uptake or intention were identified in these studies. Barriers to vaccination for the target populations were grouped using conceptual frameworks based on the Protection Motivation Theory and the World Health Organization’s Strategic Advisory Group of Experts on Immunization Working Group model and explored using the 5C psychological antecedents of vaccination.

Findings:

Although several characteristics were shown to relate to vaccine hesitancy, they do not allow for a thorough classification or proof of their individual and comparative level of influence. Understudied themes were also discovered during the review. Lack of confidence, complacency, constraints, calculation, and collective responsibility have all been highlighted as barriers to vaccination uptake among parents to different degrees.

Temporal Trends in Undervaccination: A Population-Based Cohort Study

INTRODUCTION

Monitoring the trends in undervaccination, including that because of parental vaccine refusal or delay, can inform public health responses directed at improving vaccine confidence and vaccination coverage.

METHODS

A retrospective cohort study was conducted in the Vaccine Safety Datalink. The cohort included all children born in 2004-2017 with ≥3 well-child visits between ages 2 and 23 months. Using electronic health record-based vaccination data, the average days undervaccinated was calculated for each child. Undervaccination patterns were assessed through age 23 months. Temporal trends were inspected for inflection points and were analyzed using linear regression. Nested within the cohort study, a survey was conducted to compare parent reports of vaccine refusal or delay with observed vaccination patterns. Data were analyzed in 2020.

RESULTS

The study cohort consisted of 808,170 children. The percentage of children with average days undervaccinated=0 (fully vaccinated, no delays) rose from a nadir of 47.1% for the birth year 2008 to 68.4% for the birth year 2017 (p_trend<0.001). The percentage with no vaccines rose from 0.35% for the birth year 2004 to 1.28% for the birth year 2017 (p_trend<0.001). Consistent vaccine limiting was observed in 2.04% for the birth year 2017. Omission of measles, mumps, and rubella vaccine peaked at 4.76% in the birth year 2007 and declined thereafter (p_trend<0.001). On the parent survey (response rate 60.2%), a high proportion of parents of the most undervaccinated children reported refusing or delaying vaccines.

CONCLUSIONS

In a 14-year cohort study, vaccination timeliness has improved. However, the small but increasing number of children who received no vaccines by age 23 months warrants additional attention.

Timeliness of Early Childhood Vaccinations and Undervaccination Patterns in Montana

INTRODUCTION

Early childhood vaccination rates are lower in rural areas than those in urban areas of the U.S. This study's objective is to quantify vaccine timeliness and the prevalence of undervaccination patterns in Montana and to measure the associations between timeliness and series completion by age 24 months.

METHODS

Using records from January 2015 to November 2019 in Montana's centralized immunization information system, days undervaccinated were calculated for the combined 7-vaccine series. Undervaccination patterns indicative of certain barriers to vaccination, including parental vaccine hesitancy, were identified. Using multivariable log-linked binomial regression, the association between timing of vaccine delay and not completing the combined 7-vaccine series by age 24 months was assessed. Analyses were conducted in March 2020-August 2020.

RESULTS

Among 31,422 children, 38.0% received all vaccine doses on time; 24.3% received all doses, but some were received late; and 37.7% had not completed the combined 7-vaccine series. Approximately 18.7% had an undervaccination pattern suggestive of parental vaccine hesitancy, and 19.7% started all series but were missing doses needed for multidose series completion. Although falling behind on vaccinations at any age was associated with failing to complete the combined 7-vaccine series, being late at age 12-15 months had the strongest association (adjusted prevalence ratio=3.73, 95% CI=3.56, 3.91) compared with being on time at age 12-15 months.

CONCLUSIONS

Fewer than 2 in 5 Montana children were fully vaccinated on time for the combined 7-vaccine series. To increase vaccination rates, initiatives to increase vaccine confidence and remind parents to complete vaccine series are needed.

Hepatitis B birth dose vaccination patterns in the military health System, 2014-2018

BACKGROUND

Since 2005, the universal hepatitis B (HepB) birth dose has been recommended for all medically stable infants weighing ≥2,000 g at birth. The timing of the birth dose provides a critical safeguard and prevents infection among infants born to HBsAg-positive mothers not identified prenatally. We assess infant HepB vaccination in the U.S. Department of Defense's Military Health System (MHS) to identify trends in vaccination coverage and sociodemographic factors associated with non-receipt of the birth dose, receiving the first HepB vaccine >3 days of life, and not receiving any HepB vaccine in the first 18 months of life utilizing parental refusal codes. To our knowledge, this is one of the first studies assessing trends in parental refusal of the HepB birth dose utilizing administrative claims parental refusal codes.

METHODS

We conducted a retrospective cohort analysis of MHS live births from January 1, 2014 through December 31, 2018 utilizing administrative claims data. Data were included from 44 hospitals in 24 unique states, territories, or countries. We analyzed diagnosis codes for vaccine refusal and vaccination and current procedural terminology (CPT) codes to identify vaccination patterns. Generalized linear mixed effects models with a logit link were used to assess factors associated with vaccination patterns.

RESULTS

HepB birth dose vaccination coverage increased from 79.6% in 2014 to 88.1% in 2018 (p < .0001). Refusal rates also increased from 3.7% in 2014 to 4.5% in 2018 (p < .0001). The percentage of patients with missing diagnosis codes for vaccine refusal or vaccination decreased from 16.7% in 2014 to 7.4% in 2018. Factors associated with non-receipt of the birth dose included earlier year of birth, white maternal race, higher maternal age, higher birth order, and longer infant length of stay in hospital.

CONCLUSION

Vaccination coverage for HepB birth dose is high in the MHS and increased over time; concurrently, refusal rates also increased over time. Utilizing administrative claims data has the benefit of differentiating reasons for non-receipt of the birth dose over time.

Prevalence and correlates of vaccine attitudes and behaviors in a cohort of low-income mothers

The US is facing a rise in vaccine hesitancy, delay, and refusal, though little is known about these outcomes in socio-economically disadvantaged populations. This study examines the prevalence and correlates of vaccine attitudes and behaviors in a diverse cohort of low-income mothers receiving home visiting services. Survey data were collected from 813 recipients of evidence-based home visiting services in Wisconsin from 2013 to 2018. Analyses were performed to describe outcome measures of vaccine attitudes and self-reported completion, and multivariate regressions were used to test associations between vaccine-related outcomes and hypothesized correlates. Most women (94%) reported their children were up to date on vaccines; 14.3% reported having ever delayed vaccination. A small minority disagreed that vaccines are important (5.0%), effective (5.4%), and safe (6.2%), though a larger proportion responded ambivalently (10.9%–21.9%). Participants with greater trust in health care providers reported more positive overall vaccine attitudes (B = 0.24; 95% CI = 0.17, 0.31), a lower likelihood of vaccine delay (OR = 0.57; 95% CI = 0.46, 0.73), and a greater likelihood of being up to date on vaccines (OR = 1.79, 95% CI = 1.30, 2.44). Women with greater trust in a home visitor also rated vaccines more positively (B = 0.09; 95% CI = 0.02, 0.15), and women who reported better mental health were more likely to report their children were up to date (OR = 1.05; 95% CI = 1.02, 1.09). Compared to non-Hispanic whites, American Indians and non-Hispanic blacks had poorer vaccine-related outcomes. More research on vaccine attitudes and behaviors among higher-risk populations is needed to develop tailored strategies aimed at addressing vaccine hesitancy and underimmunization.

Preferences for vaccination program attributes among parents of young infants in Shanghai, China

Compared to many other countries, China offers fewer pediatric vaccines. Future attempts to add mandatory vaccines may run counter to parents' preferences for shot-limiting. The aim of this study was to assess Chinese parents' preferences and willingness-to-pay (WTP) for programmatic attributes of vaccination services. Parents of young infants ≤3 months of age presenting at immunization clinics in Shanghai, China, in 2017 completed a discrete choice experiment (DCE) on vaccination program attributes: waiting time at the clinic, number of shots before 7 months, number of injections per visit, cost per visit, and location of the shot. We estimated preference utilities and WTP using logistic regression. In total, 590 completed the DCE. Caregivers expressed greater utility for less waiting time, fewer office visits, lower cost of vaccines, and fewer injections co-administered. Over the course of their child's first 6 months, parents were willing to pay 113 RMB ($17) to avoid an additional 10 minutes of waiting at each appointment (95% confidence interval [CI]: 213, 929), 474 RMB ($70) to avoid an additional office visit (95% CI: 241, 707), and 703 RMB ($104) to avoid an additional injection at each appointment (95% CI: 337, 1068). As China expands its list of publicly funded vaccines, public health officials will have to counter Chinese parents' strong preferences for limiting the total number of office visits and the number of injections administered at each visit, potentially through the use of combination vaccines.

Factors affecting the vaccination choices of pregnant women for their children: a systematic review of the literature

In recent years, an increase in vaccine hesitancy has led to a decrease in vaccination coverage in several countries. We conducted a systematic review of studies that assessed knowledge of and attitudes toward pediatric vaccinations, and the vaccination choices and their determinants among pregnant women. A total of 6,277 records were retrieved, and 16 full texts were included in the narrative synthesis. The published literature on the topic shows that, overall, pregnant women believe that vaccines are important for the protection of their children and the community, but various concerns and misunderstandings persist around vaccine safety and efficacy, which reduce the trust of expectant mothers in immunization. Nevertheless, such attitudes and choices vary depending on the vaccine being considered and the corresponding determinants should therefore be studied in the context of each specific vaccination. Further research on this topic is needed, particularly in non-western countries.

Countering vaccine hesitancy through immunization information systems, a narrative review

Immunization is one of the most important public health interventions to contrast infectious disease; however, many people nowadays refuse vaccination. Vaccine hesitancy (VH) is due to several factors that influence the complex decision-making process. Information technology tools might play an important role in vaccination programs. In particular, immunization information systems (IISs) have the potential to improve performance of vaccination programs and to increase vaccine uptake. This review aimed to present IIS functionalities in order to counter VH. In detail, we analyzed the automatic reminder/recall system, the interoperability of the system, the decision support system, the web page interface and the possibility to record adverse events following immunization. IIS could concretely represent a valid instrument to increase vaccine confidence, especially trust in both health-care workers and decision makers. There are not enough trials aimed to evaluate the efficacy of IIS to counter VH. Further researches might focalize on this aspect.

Development of a US trust measure to assess and monitor parental confidence in the vaccine system

OBJECTIVE

To develop a Vaccine Confidence Index (VCI) that is capable of detecting variations in parental confidence towards childhood immunizations centered on trust and concern issues that impact vaccine confidence.

METHODS

We used a web-based national poll of 893 parents of children <7 years in 2016 to assess the measures created for the Emory VCI (EVCI). EVCI measures were developed using constructs related to vaccine confidence identified by the U.S. National Vaccine Advisory Committee (i.e., "Information Environment", "Trust", "Healthcare Provider", "Attitudes and Beliefs", and "Social Norms"). Reliability for EVCI was assessed using Cronbach's alpha. Using the variables related to each of the constructs, we calculated an overall EVCI score that was then assessed against self-reported childhood vaccine receipt using chi-square and the Cochrane-Armitage trend tests.

RESULTS

Respondents' EVCI scores could range from 0 to 24, and the full range of values was observed in this sample (Mean = 17.5 (SD 4.8)). EVCI scores were significantly different (p ≤ 0.006 for all comparisons) between parents who indicated their child(ren) received routinely recommended vaccines compared with parents who indicated they had delayed or declined recommended immunizations. There was also a significant, consistent association between higher EVCI scores and greater reported vaccine receipt.

CONCLUSIONS

We developed EVCI to reliably measure parental vaccine confidence, with individuals' scores linked to parental vaccine-related attitudes, intentions, and behaviors. As such, EVCI may be a useful tool for future monitoring of both population and individual confidence in childhood immunization.

Vaccine Hesitancy in Pediatric Primary Care Practices

Understanding how pediatric practices handle parental vaccine hesitancy is important as it impacts the efficiency and effectiveness of pediatric practices. In total, 21 semi-structured interviews with pediatric practice staff within a primary care network were conducted between May 2012 and March 2013. Thematic analysis focused on the barriers and challenges of vaccine hesitancy and strategies to reduce the burden at the practice level. Barriers and challenges of vaccine hesitancy included time constraints, administrative challenges, financial challenges and strained patient-provider relationships. Strategies to minimize the burden of vaccine hesitancy included training for vaccine counseling, screening for vaccine hesitancy prior to immunization visits, tailored vaccine counseling, and primary care provider visits for follow-up immunization. Pediatric practices reported many challenges when caring for vaccine-hesitant families. Multiple strategies were identified to reduce the burden of vaccine hesitancy, which future studies should explore to determine how effective they are in increasing vaccine acceptance in pediatric practices.

Assessing Potential Confounding and Misclassification Bias When Studying the Safety of the Childhood Immunization Schedule

OBJECTIVES

Some parents are concerned the childhood immunization schedule could increase risk for allergic disorders, including asthma. To inform future safety studies of this speculated association, a parent survey was conducted to examine the risk of misclassification of vaccination status in electronic health record data, and to assess the potential for confounding if asthma risk factors varied by vaccination status.

METHODS

A survey was conducted among parents of children 19 to 35 months old at 6 medical organizations within the Vaccine Safety Datalink. Parents of children in 4 vaccination groups were surveyed: 1) no vaccines by 12 months of age and a diagnosis of parental vaccine refusal; 2) consistent vaccine limiting (≤2 vaccines per visit); 3) not consistently vaccine limiting but otherwise undervaccinated with a vaccine refusal diagnosis; and 4) fully vaccinated with no delays and no vaccine refusal. Parents were surveyed about their child's vaccination status and whether asthma risk factors existed.

RESULTS

Among a survey sample of 2043 parents, 1209 responded (59.2%). For receiving no vaccines, the observed agreement between parent report and electronic health record data was 94.0% (κ = 0.79); for receiving all vaccines with no delays, the observed agreement was 87.3% (κ = 0.73). Although most asthma risk factors (allergic rhinitis, eczema, food allergies, family asthma history) reported by parents did not differ significantly between children in the vaccination groups studied, several factors (aeroallergen sensitivity, breastfeeding) differed significantly between groups.

CONCLUSIONS

Measurement and control of disease risk factors should be carefully considered in observational studies of the safety of the immunization schedule.

Vaccination hesitancy in the antenatal period: a cross-sectional survey

BACKGROUND

Recent reports of childhood vaccination coverage in Australia have shown steadily improving vaccination coverage and narrowing differences between highest and lowest coverage regions, yet the NSW North Coast consistently has the lowest coverage rates nationally. Better understanding of parents' vaccination attitudes and actions within this region may guide strategies to improve uptake. The antenatal period is when many parents explore and consolidate vaccination attitudes and so is pivotal for study.

METHODS

Women attending public antenatal clinics at six NSW North Coast hospitals completed a 10-min cross-sectional survey capturing stage of decision-making and decisional-conflict as well as vaccination hesitancy, attitudes, intentions and actions. Unscored responses were analysed for individual items. Decisional conflict subscales were scored using published algorithms. For consented children, immunisation status was assessed at 8 months using the Australian Immunisation Register. For Likert scale items, odds ratios and Fisher's exact, chi-squared and Chasson's tests assessed differences between subgroups. Wilcoxon rank-sum tests assessed differences between subgroups for items on scales of 0-to-10 and decisional conflict sub-scale scores.

RESULTS

First-time mothers were 3 times more likely than others (OR = 3.40, 95% CI 1.34-8.60) to identify as unsure, somewhat or very hesitant. Most respondents (92.2%) wanted their new baby to receive all recommended vaccinations. Many had high or moderate levels of concern about vaccine side effects (25.4%), safety (23.6%) and effectiveness (23.1%). Increased hesitancy was associated with decreased confidence in the schedule (p < 0.001), decreased trust in child's doctor (p < 0.0001), decreased perceived protection from disease (p < 0.05) and increased decisional conflict on all measured subscales (p < 0.0001). First-time mothers had higher decisional conflict on values clarity, support and uncertainty sub-scales. By 8 months of age, 83.2% of infants were fully vaccinated. Those with none or a few minor concerns were over 8 times more likely than others to vaccinate on schedule (OR = 8.7, 1.3-56.7).

CONCLUSIONS

Importantly this study provides further strong justification to talk with women about vaccination during pregnancy and particularly to ensure that first-time mothers are offered assistance in making these important decisions, where indicated. Further research should focus on optimising the timing, content and delivery style of perinatal interventions.

Increasing Vaccination: Putting Psychological Science Into Action

Vaccination is one of the great achievements of the 20th century, yet persistent public-health problems include inadequate, delayed, and unstable vaccination uptake. Psychology offers three general propositions for understanding and intervening to increase uptake where vaccines are available and affordable. The first proposition is that thoughts and feelings can motivate getting vaccinated. Hundreds of studies have shown that risk beliefs and anticipated regret about infectious disease correlate reliably with getting vaccinated; low confidence in vaccine effectiveness and concern about safety correlate reliably with not getting vaccinated. We were surprised to find that few randomized trials have successfully changed what people think and feel about vaccines, and those few that succeeded were minimally effective in increasing uptake. The second proposition is that social processes can motivate getting vaccinated. Substantial research has shown that social norms are associated with vaccination, but few interventions examined whether normative messages increase vaccination uptake. Many experimental studies have relied on hypothetical scenarios to demonstrate that altruism and free riding (i.e., taking advantage of the protection provided by others) can affect intended behavior, but few randomized trials have tested strategies to change social processes to increase vaccination uptake. The third proposition is that interventions can facilitate vaccination directly by leveraging, but not trying to change, what people think and feel. These interventions are by far the most plentiful and effective in the literature. To increase vaccine uptake, these interventions build on existing favorable intentions by facilitating action (through reminders, prompts, and primes) and reducing barriers (through logistics and healthy defaults); these interventions also shape behavior (through incentives, sanctions, and requirements). Although identification of principles for changing thoughts and feelings to motivate vaccination is a work in progress, psychological principles can now inform the design of systems and policies to directly facilitate action.

Association Between Estimated Cumulative Vaccine Antigen Exposure Through the First 23 Months of Life and Non-Vaccine-Targeted Infections From 24 Through 47 Months of Age

IMPORTANCE

Some parents are concerned that multiple vaccines in early childhood could weaken their child's immune system. Biological data suggest that increased vaccine antigen exposure could increase the risk for infections not targeted by vaccines.

OBJECTIVE

To examine estimated cumulative vaccine antigen exposure through the first 23 months of life in children with and without non-vaccine-targeted infections from 24 through 47 months of age.

DESIGN, SETTING, AND PARTICIPANTS

A nested case-control study was conducted in 6 US health care organizations participating in the Vaccine Safety Datalink. Cases were identified by International Classification of Diseases codes for infectious diseases in the emergency department and inpatient medical settings and then validated by medical record review. Cases of non-vaccine-targeted infection were matched to controls by age, sex, health care organization site, and chronic disease status. Participants were children ages 24 through 47 months, born between January 1, 2003, and September 31, 2013, followed up until December 31, 2015.

EXPOSURES

Cumulative vaccine antigen exposure, estimated by summing the number of antigens in each vaccine dose received from birth through age 23 months.

MAIN OUTCOMES AND MEASURES

Non-vaccine-targeted infections, including upper and lower respiratory infections and gastrointestinal infections, from 24 through 47 months of age, and the association between these infections and estimated cumulative vaccine exposure from birth through 23 months. Conditional logistic regression was used to estimate matched odds ratios representing the odds of non-vaccine-targeted infections for every 30-unit increase in estimated cumulative number of antigens received.

RESULTS

Among the 944 patients (193 cases and 751 controls), the mean (SD) age was 32.5 (6.3) months, 422 (45%) were female, and 61 (7%) had a complex chronic condition. Through the first 23 months, the estimated mean (SD) cumulative vaccine antigen exposure was 240.6 (48.3) for cases and 242.9 (51.1) for controls. The between-group difference for estimated cumulative antigen exposure was -2.3 (95% CI, -10.1 to 5.4; P = .55). Among children with vs without non-vaccine-targeted infections from 24 through 47 months of age, the matched odds ratio for estimated cumulative antigen exposure through age 23 months was not significant (matched odds ratio, 0.94; 95% CI, 0.84 to 1.07).

CONCLUSIONS AND RELEVANCE

Among children from 24 through 47 months of age with emergency department and inpatient visits for infectious diseases not targeted by vaccines, compared with children without such visits, there was no significant difference in estimated cumulative vaccine antigen exposure through the first 23 months of life.

Methods for addressing "innocent bystanders" when evaluating safety of concomitant vaccines

PURPOSE

The need to develop methods for studying the safety of childhood immunization schedules has been recognized by the Institute of Medicine and Department of Health and Human Services. The recommended childhood immunization schedule includes multiple vaccines in a visit. A key concern is safety of concomitant (same day) versus separate day vaccination. This paper addresses a methodological challenge for observational studies using a self-controlled design to investigate the safety of concomitant vaccination.

METHODS

We propose a process for distinguishing which of several concomitantly administered vaccines is responsible for increased risk of an adverse event while adjusting for confounding due to relationships between effect modifying risk factors and concomitant vaccine combinations. We illustrate the approach by re-examining the known increase in risk of seizure 7 to 10 days after measles-mumps-rubella (MMR) vaccination and evaluating potential independent or modifying effects of other vaccines.

RESULTS

Initial analyses suggested that DTaP had both an independent and potentiating effect on seizure. After accounting for the relationship between age at vaccination and vaccine combination, there was little evidence for increased risk of seizure with same day administration of DTaP and MMR; incidence rate ratio, 95% confidence interval 1.2 (0.9-1.6), P value = θ.226.

CONCLUSION

We have shown that when using a self-controlled design to investigate safety of concomitant vaccination, it can be critically important to adjust for time-invariant effect modifying risk factors, such as age at time of vaccination, which are structurally related to vaccination patterns due to recommended immunization schedules.

Bias from outcome misclassification in immunization schedule safety research

PURPOSE

The Institute of Medicine recommended conducting observational studies of childhood immunization schedule safety. Such studies could be biased by outcome misclassification, leading to incorrect inferences. Using simulations, we evaluated (1) outcome positive predictive values (PPVs) as indicators of bias of an exposure-outcome association, and (2) quantitative bias analyses (QBA) for bias correction.

METHODS

Simulations were conducted based on proposed or ongoing Vaccine Safety Datalink studies. We simulated 4 studies of 2 exposure groups (children with no vaccines or on alternative schedules) and 2 baseline outcome levels (100 and 1000/100 000 person-years), with 3 relative risk (RR) levels (RR = 0.50, 1.00, and 2.00), across 1000 replications using probabilistic modeling. We quantified bias from non-differential and differential outcome misclassification, based on levels previously measured in database research (sensitivity > 95%; specificity > 99%). We calculated median outcome PPVs, median observed RRs, Type 1 error, and bias-corrected RRs following QBA.

RESULTS

We observed PPVs from 34% to 98%. With non-differential misclassification and true RR = 2.00, median bias was toward the null, with severe bias (median observed RR = 1.33) with PPV = 34% and modest bias (median observed RR = 1.83) with PPV = 83%. With differential misclassification, PPVs did not reflect median bias, and there was Type 1 error of 100% with PPV = 90%. QBA was generally effective in correcting misclassification bias.

CONCLUSIONS

In immunization schedule studies, outcome misclassification may be non-differential or differential to exposure. Overall outcome PPVs do not reflect the distribution of false positives by exposure and are poor indicators of bias in individual studies. Our results support QBA for immunization schedule safety research.

Rotavirus vaccination rate disparities seen among infants with acute gastroenteritis in Georgia

OBJECTIVE

Rotavirus (RV) is one of the most common diarrheal diseases affecting children less than 5 years of age. RV vaccines have greatly reduced this burden in the United States. The purpose of this study was to determine possible disparities and socio-economic differences in RV vaccination rates.

DESIGN

Children with acute gastroenteritis were enrolled. Stool was tested for presence of rotavirus using an enzyme immunoassay kit. Vaccination records were abstracted from the state immunization registry and healthcare providers to examine complete and incomplete vaccination status. Cases were identified as children receiving a complete RV dose series and controls were identified as children with incomplete RV doses. A logistic regression model was used to determine disparities seen amongst children with incomplete vaccination status.

RESULTS

Racial differences between Black and white infants for RV vaccination rates were not significant when controlling for covariates (OR 1.15, 95% CI 0.74-1.78); however ethnicity (p-value .0230), age at onset of illness (p-value .0004), birth year (p-value < .0001), and DTaP vaccination status (p-value < .0001) were all significant in determining vaccination status for children.

CONCLUSIONS

Racial disparities and socio-economic differences are not determinants in rotavirus vaccination rates; however, age and ethnicity have an effect on RV vaccine status.

Influences on university students' intention to receive recommended vaccines: a cross-sectional survey

OBJECTIVES

To explore predictors of university students' intention to receive a recommended vaccine and the main sources of vaccine-related information accessed by university students.

SETTING

Participants were recruited from University College London (UK) in summer 2015.

PARTICIPANTS

177 university students participated. The majority of participants were female (58%), White (68%) and had no religion (58%). Participants were aged 18 to 42 (mean age=23.6).

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measures included vaccine attitude, perceived subjective norm, perceived behavioural control, perceived self-efficacy, past receipt of recommended childhood vaccines, perceived adverse reaction to past vaccination and needle fear. As a secondary outcome sources of vaccine-related information were assessed.

RESULTS

Students classified as high intenders were more likely to have received all recommended childhood vaccines (OR 3.57; 95% CI 1.21 to 10.59; p=0.022), be less afraid of needles (OR 2.44; 95% CI 1.12 to 5.36; p=0.026) and to have lived in the UK until at least the age of 4 compared with those not living in the UK until at least the age of 4 (OR 0.39; 95% CI 0.18 to 0.83; p=0.015) and those who lived both in the UK and elsewhere (OR 0.42; 95% CI 0.04 to 4.06; p=0.424). The multivariable model explained 25.5% of variance in intention to receive a recommended vaccine. The internet was the most commonly reported source of vaccination information.

CONCLUSIONS

Findings provide an indication of the factors that may need to be addressed by interventions aiming to increase uptake of recommended vaccines in a university population. Future research is recommended using a prospective cohort design.

Assessing misclassification of vaccination status: Implications for studies of the safety of the childhood immunization schedule

BACKGROUND

To address public concern about the safety of the childhood immunization schedule, the Institute of Medicine recommended observational studies comparing adverse health outcomes of fully vaccinated children to children under-vaccinated due to parental choice. Misclassification of vaccination status could bias such studies.

OBJECTIVE

To assess risk of misclassification of vaccination status within the Vaccine Safety Datalink (VSD).

DESIGN/METHODS

A retrospective cohort study was conducted in three phases. In phase 1, electronic health record (EHR) data were used to identify patterns of under-vaccination during the first 24months of life potentially due to parental choice. In phase 2, a random sample of records of under-vaccinated children was manually reviewed. In phase 3, a separate sample of parents were surveyed to assess whether EHR data accurately reflected their child's vaccination status. Phases 1 and 2 were conducted at 6 VSD sites, phase 3 at 1 site.

RESULTS

The study cohort included 361,901 children born 2004 through 2012. By 24months of age, 198,249 (54.8%) were fully vaccinated with no delays, 84,698 (23.4%) experienced delays but were fully vaccinated by 24months of age, 4865 (1.3%) received no vaccines, 3789 (1.0%) delayed starting vaccination until ≥4months of age, 4781 (1.3%) had consistent vaccine-limiting (≤2 vaccines per visit), and the remaining 65,519 (18.1%) were missing vaccine series or doses. When a diagnosis code for vaccine refusal was present in EHR data, encounter notes confirmed vaccine refusal as the reason for under-vaccination for nearly 100% of sampled records. Parent surveys confirmed these findings. Parents of under-vaccinated children were more likely to report visiting an alternative medical provider than parents of fully vaccinated children.

CONCLUSIONS

Specific groups of children, under-vaccinated due to parental choice, can be identified with relatively low likelihood of misclassification of vaccination status using EHR-based vaccine data and diagnosis codes.

Parents' Perspectives on How to Improve the Childhood Vaccination Process

Few national studies have asked parents how to improve the childhood vaccination process. We surveyed a nationally representative online panel of parents on how to improve this process, rationales for nonstandard approaches, and alternatives to the standard schedule. Twelve percent of the 1222 respondents reported using nonstandard approaches: 3.2% used a specific schedule, 6.0% had no specific schedule, and 2.5% declined all vaccinations. The most common rationales were that too many vaccines are given at once, and discomfort with vaccine ingredients. Regarding how to improve the process, parents using the standard schedule most often said nothing could be improved (51%), or better vaccine information (22%). Those using nonstandard approaches most often would have liked more choice (40%) or better vaccine information (26%). Parents' experiences with the vaccination process could be improved by offering information prior to visits, giving more information about side effects, and allowing more flexibility about vaccine scheduling.

Vaccine shot-limiting: Estimating the prevalence, indicators, and impact on vaccination status - Michigan, 2012

BACKGROUND

Concerns regarding vaccine safety and pain have prompted certain parents to limit the number of shots their child receives per visit. We estimated the prevalence of shot-limited children in Michigan, described their characteristics, assessed whether shot-limited children were up-to-date on recommended vaccinations, and investigated possible intervention points for vaccination education.

METHODS

We analyzed vaccination registry and birth record data of children born in Michigan during 2012 who had ⩾2 vaccination visits, with ⩾1 visits after age 5months. Shot-limited was defined as receiving ⩽2 shots at all visits through age 24months. Nonlimited children received >2 shots at ⩾1 visits. Up-to-date vaccination was based on receipt of a seven-vaccine series and was determined at ages 24months and 35months. Risk ratios (RR) were calculated using risk regression.

RESULTS

Of 101,443 children, a total of 2,967 (3%) children were shot-limited. Mothers of shot-limited children were more likely to be white (RR: 1.2; 95% confidence interval [CI]: 1.2-1.2), college graduate (RR: 1.9; 95% CI: 1.9-2.0), and married (RR: 1.5; 95% CI: 1.5-1.5). Compared with nonlimited children, shot-limited children were more likely to be born in a nonhospital setting (RR: 11.7; 95% CI: 9.4-14.6) and have a midwife attendant (RR: 1.9; 95% CI: 1.7-2.1). Shot-limited children were less likely to be up-to-date on recommended vaccinations (RR: 0.2; 95% CI: 0.2-0.3); this association was stronger for those with a midwife birth attendant (RR: 0.1; 95% CI: 0.1-0.2) rather than a medical doctor (RR: 0.3; 95% CI: 0.2-0.3).

CONCLUSIONS

Shot-limited children are less likely to be up-to-date on vaccinations, possibly leading to increased risk for vaccine-preventable diseases. This association was stronger for those with a midwife birth attendant. This analysis should prompt targeted education, such as to midwives, concerning risks associated with shot-limiting behavior.

A qualitative systematic review of factors influencing parents' vaccination decision-making in the United Kingdom

BACKGROUND

High uptake of vaccinations is crucial for disease prevention. Although overall uptake of childhood immunisations is high in the United Kingdom (UK), pockets of lower uptake remain. Novel systematic methods have not been employed when reviewing the qualitative literature examining parents' vaccination decisions.

AIMS

We aimed to conduct a qualitative systematic review of studies in the UK to understand factors influencing parental decisions to vaccinate a child.

METHODS

On 12/2/14 we searched PsycINFO, MEDLINE, CINAHL plus, Embase, Social Policy and Practice and Web of Science for studies using qualitative methods and reporting reasons why parents in the UK had or had not immunised their child. Participant quotes and authors' interpretations of qualitative data were extracted from the results of articles. Thematic synthesis was used to develop higher-order themes (conducted in 2015).

RESULTS

34 papers were included. Two types of decision-making had been adopted: non-deliberative and deliberative. With non-deliberative decisions parents felt they had no choice, were happy to comply and/or relied on social norms. Deliberative decisions involved weighing up the risks and benefits, considering others' advice/experiences and social judgement. Emotions affected deliberative decision-making. Trust in information and vaccine stakeholders was integral to all decision-making. Practical issues affected those who intended to vaccinate.

CONCLUSIONS

Parents adopted two different approaches to decision-making about childhood vaccinations. By understanding more about the mechanisms underpinning parents' vaccination behaviour, in collaboration with vaccine stakeholders, we can better design interventions to enhance informed uptake.

Undervaccination with diphtheria, tetanus, and pertussis vaccine: National trends and association with pertussis risk in young children

BACKGROUND

The high coverage for ≥3 pertussis vaccine doses among Taiwanese children might not imply timely vaccination. Recently, resurgence of pertussis and challenges with availability of DTaP-IPV-Hib prompted this study.

METHODS

In the 1996-2012 national birth cohort, we calculated the prevalence and days of undervaccination against pertussis by age 36 months. We also compared the odds of undervaccination in each laboratory-confirmed pertussis patient at ages 3-35 months with sex-, residence-, and age-matched controls from the general population, using conditional logistic regression.

RESULTS

The prevalence of undervaccination was 60.6% (median 16 days) and decreasing (p < 0.0001). Among 145 cases and 2,900 controls, 58 (40.0%) and 721 (24.9%) were undervaccinated (OR 2.28, 95% CI 1.57-3.31). The attributable risk percent was 22.5% (95% CI 14.5-27.9).

CONCLUSIONS

Undervaccination was decreasing. Approximately up to one-fifth pertussis cases in children aged 3-35 months could have been prevented with on-time vaccination.

Parental experiences with vaccine information statements: Implications for timing, delivery, and parent-provider immunization communication

OBJECTIVE

We examined Vaccine Information Statements (VIS) dissemination practices and parental use and perceptions.

METHODS

We conducted a national online panel survey of 2603 US parents of children aged <7. Primary outcomes included reported VIS receipt, delivery timing, reading experiences, and perceived utility.

RESULTS

Most parents received a VIS (77.2%; [95% CI: 74.5-79.7%]), 59.7% [56.6-62.7%] before vaccination but 14.5% [12.5-16.8%] reported receiving it after their child's immunization; 15.1% [13.0-17.6%] were unsure of receipt status or timing; another 10.7% [9.0-12.6%] reported non-receipt of a VIS. Less than half who received a VIS before vaccination completed it before vaccination (46.2% [42.4, 50.0%]), but most who read at least some found the information useful (95.7% [93.8-97.0%]). Parents who delayed or refused at least one recommended non-influenza vaccine reported fewer opportunities to ask providers VIS questions.

CONCLUSIONS

Most parents report receiving VIS before vaccination as per federal guidelines. Continued effort is needed to enhance VIS distribution practice and parent-provider VIS content communication.

Parents' confidence in recommended childhood vaccinations: Extending the assessment, expanding the context

There has been significant and growing interest in vaccine hesitancy and confidence in the United States as well as across the globe. While studies have used confidence measures, few studies have provided in-depth assessments and no studies have assessed parents' confidence in vaccines in relationship to other frequently recommended health-related products for young children. This study used a nationally representative sample of 1000 US parents to identify confidence levels for recommended vaccinations, antibiotics, over-the-counter (OTC) medicines, and vitamins for children. The analyses examined associations between confidence ratings, vaccination behaviors and intentions, and trust in healthcare provider, along with associations between confidence ratings and use of the other health-related products. Parents' confidence in vaccines was relatively high and high relative to antibiotics, OTC medicines and vitamins. For all 4 health-related products examined, past product experience and knowledge of bad or adverse outcomes negatively impacted parents' confidence levels. Confidence levels were associated with both trust in advice from their child's healthcare provider and acceptance of healthcare provider recommendations. Parents in some groups, such as those with lower income and education levels, were more likely to have less confidence not just in vaccines, but also in antibiotics and OTC medicines for children. Overall, the findings extend understanding of vaccine confidence, including by placing it into a broader context.

Vaccine Delays, Refusals, and Patient Dismissals: A Survey of Pediatricians

BACKGROUND

Parental noncompliance with the American Academy of Pediatrics and Centers for Disease Control and Prevention immunization schedule is an increasing public health concern. We examined the frequency of requests for vaccine delays and refusals and the impact on US pediatricians' behavior.

METHODS

Using national American Academy of Pediatrics Periodic Surveys from 2006 and 2013, we describe pediatrician perceptions of prevalence of (1) vaccine refusals and delays, (2) parental reasons for refusals and/or delays, and (3) physician dismissals. Questions about vaccine delays were asked only in 2013. We examined the frequency, reasons for, and management of both vaccine refusals and delays by using bivariate and multivariable analyses, which were controlled for practice characteristics, demographics, and survey year.

RESULTS

The proportion of pediatricians reporting parental vaccine refusals increased from 74.5% in 2006 to 87.0% in 2013 (P < .001). Pediatricians perceive that parents are increasingly refusing vaccinations because parents believe they are unnecessary (63.4% in 2006 vs 73.1% in 2013; P = .002). A total of 75.0% of pediatricians reported that parents delay vaccines because of concern about discomfort, and 72.5% indicated that they delay because of concern for immune system burden. In 2006, 6.1% of pediatricians reported "always" dismissing patients for continued vaccine refusal, and by 2013 that percentage increased to 11.7% (P = .004).

CONCLUSIONS

Pediatricians reported increased vaccine refusal between 2006 and 2013. They perceive that vaccine-refusing parents increasingly believe that immunizations are unnecessary. Pediatricians continue to provide vaccine education but are also dismissing patients at higher rates.

Countering Vaccine Hesitancy

Immunizations have led to a significant decrease in rates of vaccine-preventable diseases and have made a significant impact on the health of children. However, some parents express concerns about vaccine safety and the necessity of vaccines. The concerns of parents range from hesitancy about some immunizations to refusal of all vaccines. This clinical report provides information about addressing parental concerns about vaccination.

Vaccination Confidence and Parental Refusal/Delay of Early Childhood Vaccines

OBJECTIVE

To support efforts to address parental hesitancy towards early childhood vaccination, we sought to validate the Vaccination Confidence Scale using data from a large, population-based sample of U.S. parents.

METHODS

We used weighted data from 9,354 parents who completed the 2011 National Immunization Survey. Parents reported on the immunization history of a 19- to 35-month-old child in their households. Healthcare providers then verified children's vaccination status for vaccines including measles, mumps, and rubella (MMR), varicella, and seasonal flu. We used separate multivariable logistic regression models to assess associations between parents' mean scores on the 8-item Vaccination Confidence Scale and vaccine refusal, vaccine delay, and vaccination status.

RESULTS

A substantial minority of parents reported a history of vaccine refusal (15%) or delay (27%). Vaccination confidence was negatively associated with refusal of any vaccine (odds ratio [OR] = 0.58, 95% confidence interval [CI], 0.54-0.63) as well as refusal of MMR, varicella, and flu vaccines specifically. Negative associations between vaccination confidence and measures of vaccine delay were more moderate, including delay of any vaccine (OR = 0.81, 95% CI, 0.76-0.86). Vaccination confidence was positively associated with having received vaccines, including MMR (OR = 1.53, 95% CI, 1.40-1.68), varicella (OR = 1.54, 95% CI, 1.42-1.66), and flu vaccines (OR = 1.32, 95% CI, 1.23-1.42).

CONCLUSIONS

Vaccination confidence was consistently associated with early childhood vaccination behavior across multiple vaccine types. Our findings support expanding the application of the Vaccination Confidence Scale to measure vaccination beliefs among parents of young children.

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.

Characteristics of Physicians Who Dismiss Families for Refusing Vaccines

BACKGROUND AND OBJECTIVES

Physicians dismissing families who refuse vaccines from their practices is controversial. We assessed the following among pediatricians (Peds) and family physicians (FPs): (1) reported prevalence of parental refusal of 1 or more vaccines in the infant series; (2) physician response to refusal; and (3) the association between often/always dismissing families and provider/practice characteristics and state exemption laws.

METHODS

Nationally representative survey conducted June to October 2012. A multivariable analysis assessed association of often/always dismissing families with physician/practice characteristics, state philosophical exemption policy, and degree of difficulty obtaining nonmedical exemptions.

RESULTS

The response rate was 66% (534/815). Overall, 83% of physicians reported that in a typical month, ≥1% of parents refused 1 or more infant vaccines, and 20% reported that >5% of parents refused. Fifty-one percent reported always/often requiring parents to sign a form if they refused (Peds 64%, FP 29%, P < .0001); 21% of Peds and 4% of FPs reported always/often dismissing families if they refused ≥1 vaccine. Peds only were further analyzed because few FPs dismissed families. Peds who dismissed families were more likely to be in private practice (adjusted odds ratio [aOR] 4.90, 95% confidence interval [CI] 1.40-17.19), from the South (aOR 4.07, 95% CI 1.08-15.31), and reside in a state without a philosophical exemption law (aOR 3.70, 95% CI 1.74-7.85).

CONCLUSIONS

Almost all physicians encounter parents who refuse infant vaccines. One-fifth of Peds report dismissing families who refuse, but there is substantial variation in this practice. Given the frequency of dismissal, the impact of this practice on vaccine refusers and on pediatric practices should be studied.