Adherence to Timely Vaccinations in the United States.

OBJECTIVES: To estimate (1) the proportion of children not adhering to the Advisory Committee on Immunization Practices (ACIP) recommended early childhood immunization schedule and (2) associations between schedule adherence, sociodemographic characteristics, and up-to-date immunization status by 19 to 35 months of age. METHODS: We used 2014 National Immunization Survey provider-verified vaccination data to classify vaccination patterns as "recommended" (ie, in line with ACIP dose- and age-specific recommendations), "alternate" (ie, in line with either limiting the number of shots per visit or skipping at least 1 vaccine series), or "unknown or unclassifiable" (ie, not in line with ACIP recommendations or clearly limiting shots per visit or vaccine series). We evaluated the association between vaccination patterns and up-to-date status for all ACIP-recommended vaccinations (including rotavirus and hepatitis A vaccines) using Poisson regression. RESULTS: The majority of children's patterns were classified as "recommended" (63%), with 23% and 14% following alternate or unknown or unclassifiable patterns, respectively; 58% of children were up-to-date with all ACIP-recommended immunizations by 19 to 35 months. Not being up-to-date was associated with alternate (prevalence ratio = 4.2, 95% confidence interval: 3.9-4.5) and unknown or unclassifiable (prevalence ratio = 2.4, 95% confidence interval: 2.2-2.7) patterns. CONCLUSIONS: High vaccine coverage by 19 to 35 months of age may miss nonadherence to the recommended immunization schedule in the first 18 months of life, leaving children vulnerable to preventable diseases. With more than one-third of US children not following the ACIP schedule, targeted interventions are needed to minimize vaccine delays and disease susceptibility.

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.

Development of a measure to assess vaccine confidence among men who have sex with men.

BACKGROUND: Recent serogroup C meningococcal disease outbreaks led to meningococcal vaccine recommendations for Southern California men who have sex with men (MSM). Assessment of vaccine confidence is critical to improving vaccine coverage in the context of disease outbreaks wherein immunization(s) are recommended. METHODS: We surveyed MSM using venue-based sampling and began development of the vaccine confidence index (VCI) with 30 survey items corresponding to trust- and safety-related perceptions. We performed exploratory factor analyses and computed the Cronbach's alpha coefficient to assess internal consistency of the VCI. We created a categorical confidence variable (low, medium, and high confidence) and conducted bivariate and multivariate analyses to evaluate associations with reported confidence and immunization uptake. RESULTS: Ten survey items were included in the final VCI and formed the confidence measure. Participants with low confidence had the lowest levels of reported uptake for both meningococcal vaccines. Confidence differed significantly (p ≤ 0.05) between MSM who indicated they received vaccines recommended within the context of the outbreak and those who did not. CONCLUSIONS: Our VCI is sensitive to a number of issues that may influence vaccine confidence. It is useful for assessing MSM trust and acceptance of recommended immunizations and may be used to inform intervention development.

What is 'confidence' and what could affect it?: A qualitative study of mothers who are hesitant about vaccines.

BACKGROUND: Public confidence in immunization is critical to maintaining high vaccine-coverage rates needed to protect individuals and communities from vaccine-preventable diseases. Recent attention has been placed on factors influencing confidence in vaccination in the US and globally, but comprehensive understanding of what drives or hinders confidence in childhood vaccination is yet to be reached. As such, assessing parents' confidence in childhood vaccination and the ways in which educational materials affect confidence is needed. OBJECTIVE: We sought to (1) learn how mothers who are hesitant about vaccination characterize confidence in health-related products for young children, including the recommended vaccines; (2) gain insights on what influences vaccine confidence beliefs; and (3) assess whether short, education materials affect parental confidence in childhood vaccinations. METHODS: Eight moderator-lead focus groups (n=61), stratified by socioeconomic status, were undertaken with mothers of children 5years of age of less who are hesitant about vaccines. Four of the groups were held in the Philadelphia, PA area and four were held in the San Francisco/Oakland, CA area. Three educational material pairs, each consisting of a 2-3min video and an infographic poster about an immunization-related topic, were reviewed and assessed for influence on confidence. RESULTS: Qualitative data analysis was used to identify overarching themes across the focus groups. Themes, insights, and illustrative quotes were identified and provided for each of the major discussion areas: primary health concerns for young children; confidence beliefs and perceptions, including for recommended vaccines; facilitators and barriers to confidence; and reactions to the educational materials. CONCLUSIONS: Results provide helpful insights into how mothers who are hesitant about vaccines perceive confidence in childhood vaccines and health-related products, suggestions for how to improve confidence, and support for the value and use of short videos as part of vaccination education efforts. Findings can aid those developing vaccination education materials and resources designed to foster vaccine confidence.