Pediatricians' vaccine attitudes and practices before and after a major measles outbreak

Revisiting the 2014-15 Disneyland measles outbreak and its influence on pediatric vaccinations

The 2014-15 Disneyland measles outbreak that began at the California theme park in December 2014 sparked an international conversation regarding measles, vaccine hesitancy, and vaccine policies. The outbreak capped a year with the highest number of measles cases reported in two decades and came amidst increasing trends in nonmedical vaccine exemptions in California and elsewhere. Because of its sensational story line and spread among unvaccinated populations, the outbreak received a high level of media coverage that focused on vaccine hesitancy as a primary driver of the outbreak. This media coverage and the ostensible public support for vaccines that followed led some to hypothesize that the outbreak might have a "Disneyland effect," or a positive influence on the uptake of pediatric measles vaccine. This article reviews the facts of the outbreak and its context, and explores the evidence for the Disneyland outbreak causing an influence on U.S. pediatric vaccine-related beliefs and behaviors.

Trends in the uptake of pediatric measles-containing vaccine in the United States: A Disneyland effect?

BACKGROUND

The measles outbreak that began in December 2014 at the California Disneyland theme park in the United States (U.S.) received a high amount of media attention. Media attention can influence health-related behaviors. We investigated the effect of the Disneyland outbreak on measles-containing vaccine (MCV) uptake among U.S. children.

METHODS

We used 2012-2017 National Immunization Survey-Child (NIS-Child) data to examine MCV uptake among U.S. children by 19 months of age. We classified MCV coverage among birth cohorts as exposed based on age at the time of the outbreak. A difference-in-differences design with adjustment for categorical birth cohort was implemented in base models to estimate the exposure effect on the outcomes, ≥1-dose MCV coverage or age at first MCV dose, with pneumococcal conjugate vaccination as a control. Primary analyses included this model adjusted for geographic region, maternal education, race/ethnicity, household income, and insurance status, and an exposure-interaction term with maternal education. All analyses included sampling weights.

RESULTS

The study population represented 34,471,357 children. In base models, the Disneyland outbreak was associated with a 1.0% (95% CI: 0.2%, 1.8%) increase in ≥1-dose MCV coverage and a 6.6 (95% CI: 4.8, 8.5)-day decrease in MCV administration age. In primary analyses, the outbreak was associated with a 3.9% (95% CI: 3.1%, 4.8%) increase in ≥1-dose MCV coverage among children of college-educated mothers, and a 3.2% (95% CI: 0.6%, 5.9%) decrease among children of mothers earning less than a high school degree. Decreases in MCV administration age ranging from 5.9 (95% CI: 3.3, 8.5) to 9.1 (95% CI: 6.8, 11.4) days were observed across maternal education categories.

CONCLUSIONS

The Disneyland outbreak was associated with differential effects on MCV coverage by maternal education and decreases in MCV administration age among U.S. children. These findings may provide useful insights to inform methods to address pediatric MCV undervaccination.

A qualitative study examining pediatric clinicians' perceptions of delayed vaccine schedules

OBJECTIVE

To explore pediatric clinicians' attitudes, beliefs, and perceived social norms about the impact of delayed vaccine schedules on the clinical management of their patients.

METHODS

We conducted 30 semi-structured qualitative interviews with academic (Infectious Diseases, Emergency Medicine) and community pediatric clinicians (General Pediatrics) to explore clinicians' perspectives on how delayed schedules influence their clinical management of patients. The interview guide was based on the Theory of Planned Behavior. We analyzed interview transcripts using both an inductive and deductive thematic approach.

RESULTS

The pediatric clinicians in our study overwhelmingly supported the recommended schedule, sought guidance on approaches to navigating conversations with vaccine hesitant families, and desired more evidence to effectively promote on-time vaccination. Clinicians described how delayed schedules have consequences for sick children (e.g., increased antibiotics, laboratory tests, emergency department visits) and healthy children (e.g., increased vaccine visits, out-of-pocket costs, fears among children receiving frequent shots). Clinicians stated that delayed schedules also negatively impact pediatric practices (e.g., increased time counseling patients, staff burden, clogged clinic space, unpredictable vaccine utilization, costs).

CONCLUSIONS

Pediatric clinicians perceive that delayed vaccine schedules negatively affect patients, pediatric practices, the healthcare system, and society. Future research should quantify the consequences of delayed schedules and identify strategies that promote vaccine adherence. Results from future studies can better support clinician-parent conversations about vaccine hesitancy, guide decision-makers about practice-level approaches to vaccine schedules, and advise payors and policymakers regarding vaccine-related policies.