Of all the opportunities we miss in life, one of the most regrettable is the opportunity to provide a life-saving immunization to a patient at risk. Vaccination rates in the United States show room for substantial improvement. The most recent National Immunization Survey showed that, among children aged 19 to 35 months, there was little change in vaccination rates between 2013 and 2014, with the lowest rates hovering around 72% for rotavirus and the first hepatitis B vaccine, and up to around 94% for the diphtheria and tetanus toxoids and acellular pertussis, poliovirus, and Haemophilus influenzae type b series vaccines.¹

Vaccine Rates in Children versus Adults

Linda Y. Fu, MD, MS, Pediatrician, Goldberg Center for Community Pediatric Health, Children's National Health System, Washington, DC, and colleagues studied 20,181 medical encounters comprising 2076 pediatric patients, and found that only 72.7% of children were up to date with their immunizations.² The authors concluded that missed opportunities were a primary reason for low immunization rates, and a common occurrence.

Although it's tempting to believe that negative parental beliefs about vaccines are the primary cause of missed opportunities (and, therefore, underimmunization in children), this has not been found to be true. In a recent study of measles vaccine rates in children and adolescents, Philip J. Smith, PhD, Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases, Immunization Services Division, Atlanta, GA, and colleagues found that approximately 75% of missed opportunities were caused by something other than parents' vaccine-related beliefs.³ Other reasons for missed opportunities must be examined.

Immunizations for children are bolstered by state and federal regulations for participation in programs such as the Women, Infants, and Children program,⁴ and school attendance. Interventions to ensure childhood immunizations vary, and include parental education about vaccine effects, review of immunization schedules, referrals to providers, and requirements to immunize or declare exemption on limited grounds.

There is no question that this type of oversight positively impacts childhood immunizations, but similar program requirements don't exist for adults. Their noticeably lower immunization rates reflect this lack of scrutiny. For example, the Advisory Committee on Immunization Practices recommends herpes zoster vaccination for adults aged ≥ 60 years.⁵ Although herpes zoster vaccination coverage improved slightly from the previous year, it was estimated that in 2013 only 24.2% of eligible adults received the vaccine-6% below the modest Healthy People 2020 target of 30%. The rate for the tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine was even lower, with an overall rate of only 17.2% among people aged ≥ 19 years.³

Addressing Missed Opportunities for Adult Vaccinations

What can we do about all of these missed opportunities? The problem is multifactorial, but many of the reasons for the current status of national immunization rates fall within 3 broad categories: (1) patient/family factors, such as missed appointments, lack of awareness that an immunization is due, refusal of vaccine, or a vaccine that is not affordable; (2) clinician factors, such as lack of awareness of vaccine schedules, failure to review the patient record for preventive health needs, or belief that the patient is ineligible because of minor illness or other reasons that are not actual-vaccine contraindications and (3) system factors, such as lack of a clinic reminder system for immunizations, not stocking the necessary vaccines, inflexible immunization appointments, lack of standing orders to immunize, or patient immunization records that are not available for review at the time of service.

An examination of the contributing problems allows consideration of possible solutions. Each of the above factors will require further exploration to determine the root cause of the barrier. For example, if patients are missing appointments, is this because of a transportation problem, work schedules that conflict with clinic schedules, the lack of an appointment reminder system, or some other reason?

Conclusion

At any given practice site, several factors may be at play, preventing clinicians from adequately addressing their patients' immunization needs. Providers, clinical staff, and the administrative team can examine the factors unique to their practice site and implement quality improvement programs to impact change.

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References

1. Hill HA, Elam-Evans LD, Yankey D, et al. National, state, and selected local area vaccination coverage among children aged 19-35 months-United States, 2014. MMWR Morb Mortal Wkly Rep. 2015;64:889-896.
2. Fu LY, Zook K, Gingold J, et al. Frequent vaccination missed opportunities at primary care encounters contribute to underimmunization. J Pediatr. 2015;166:412-417.
3. Smith PJ, Marcuse EK, Seward JF, et al. Children and adolescents unvaccinated against measles: geographic clustering, parents' beliefs, and missed opportunities. Public Health Rep. 2015;130:485-504.
4. US Department of Agriculture. Women, Infants and Children (WIC). www.fns.usda.gov/wic/immunization-screening-and-referral-wic. Accessed January 20, 2016.
5. Williams WW, Lu P, O'Halloran A, et al. Vaccination coverage among adults, excluding influenza vaccination-United States, 2013. MMWR Morb Mortal Wkly Rep. 2015;64:95-102.