Delays in immunization have potentially serious health consequences.

When children are not administered vaccinations according to the recommended schedule, they not only fail to receive timely protection from preventable diseases at a time when they are most vulnerable, but also increase their risk of never fully completing the vaccination course. Both outcomes compromise a successful childhood immunization program. Although current data suggest that vaccination rates are near 95% for school-aged children in the US, the rate of timely vaccination is much lower. A number of large studies have found that the majority of children are not currently vaccinated on schedule. Moreover, immunization levels for 2- to 3-year-old children have reached a plateau. It is essential to recognize that low overall rates of the targeted diseases mask the persistent threat they pose if adherence to vaccination schedules declines. A delay in one vaccine will produce a domino effect if catch-up adjustments in scheduled visits are not implemented aggressively. Published reports have demonstrated that failure to adhere to scheduled booster immunizations, not just the initial inoculation, results in resurgence of disease. Children fall off the vaccination schedule for a variety of reasons. Although many studies suggest that inadequate availability to healthcare is not a major determinant of delayed immunization, it still factors into parental decisions. Parents should be reminded of available healthcare options. From the clinician's end, computerization of healthcare records should allow for the generation of reminders. It is vital for clinicians to be aware that there are few contraindications to vaccination. They should also be prepared to address parental concerns regarding the safety of vaccines and should not hesitate to use topical analgesics or distraction techniques to facilitate inoculation. With the anticipation of several novel vaccines being added to the childhood and adolescent immunization schedule in the future, pediatricians face new challenges to not only provide every vaccination, but to do so in a timely manner. A lack of willingness on the part of the parent, or, occasionally, on the part of the clinician, to have multiple vaccines administered to the child during a single visit has been shown to be a significant cause of delayed vaccination. Since combination vaccines reduce the number of shots that need to be administered, the use of combination vaccines may provide the best opportunity to simplify the immunization schedule, increasing adherence in the process. Improved adherence to established schedules may present a major opportunity to further protect children from disease.