Description

• A decision by a patient or parent to delay or refuse a vaccine recommended by a health care provider
• Comprises a range of behaviors from unquestioning acceptance of vaccines to cautious or selective acceptance to refusal of all vaccines
• Influenced by the interaction of several factors related to: confidence, complacency, and convenience
  • Confidence: lack of trust in vaccines, health care providers, and/or health care system
  • Complacency: low prioritization of vaccination related to low perceived risk of vaccine preventable diseases
  • Convenience: barriers to accessing immunization services (e.g., vaccine cost or difficulty getting to immunization provider)

Epidemiology

• Majority of adults in the United States believe vaccination is extremely or very important, but increasing proportion believe vaccines are more dangerous than diseases they prevent.
• Majority of pediatricians report >1 vaccine refusal/month.
• >1/3 of pediatricians will accept requests to delay certain vaccines, but fewer than 10% agree with such requests.
• Among a cohort of undervaccinated young children, 13% were undervaccinated due to parental choice.
• Rate of infants who receive first vaccine dose at age 4 to 5 months increased from ~50/10,000 to 100/10,000 across five successive birth cohorts (2004 to 2008).
• In the 2015 to 2016 school year, exemption rates for kindergarten school entry requirements rose from 0.4% to 6.2% across U.S. states.

Risk Factors

Because of the heterogeneity of vaccine hesitancy, there is no one singular set of risk factors. However, contributors to refusal include:

• Less experience with vaccine preventable diseases due to decreased disease incidence. This leads to underappreciation of disease risk and severity and parents may question need for vaccines.
• Vaccine safety concerns—especially as concerns about risk of vaccine—preventable diseases decreases, parents may worry more about potential risks of vaccination.
• Rapid dissemination of information increases likelihood of access to misinformation about vaccines, which may reinforce vaccine safety concerns,
• Anti-vaccine advocacy by prominent public figures that call attention to anti-vaccine beliefs.
• Increase in scientific denialism, which is rejection of facts for which there is well-established scientific consensus.

General Prevention

• Early communication about vaccines with parents can help identify and address concerns to prevent vaccine refusal or delay.
• Opportunities may include prenatal visits, in the nursery prior to discharge from the hospital after or at the newborn visit.

Commonly Associated Conditions

• For some parents, vaccine refusal may be associated with refusal of other health care interventions.
• Some parents may accept all recommended vaccines but request an alternative schedule. Alternative vaccine schedules spread out the recommended vaccine doses, resulting in immunization delay for some vaccines.
• Reasons for request of alternative vaccine schedules:
  • Belief that receiving multiple injections at same time overwhelms the immune system
  • Belief that recommended schedule exposes infants to too much aluminum