To our knowledge, this is the first study to capture pediatricians' attitudes about ACISs. Our results support our hypothesis that parents regularly ask for ACISs and most pediatricians report they are comfortable using ACISs when parents do so. Importantly, however, we found that pediatricians prioritize specific vaccines over others when considering these ACIS requests. We found that pediatricians were least willing to consider using ACISs for DTaP vaccine, PCV, and Hib vaccine and were least comfortable delaying these vaccines for >4 months.
We also found that pediatricians in a neighborhood or community clinic were less comfortable using ACISs if requested than were pediatricians in a 1- or 2-physician practice. Although the reasons for this are unclear, other investigators found associations between practice type and size and timely receipt of childhood vaccinations.24,25
Perhaps a perception of low continuity of care and administrative and resource constraints may account for the reduced likelihood of pediatricians in some practices being comfortable using ACISs.
Our findings have several implications. First, parents' requests for ACISs from Washington State pediatricians who responded to our survey were common. Also, although we acknowledge that varying definitions of an ACIS have been used, our results seem consistent with those from recently published national surveys in which 13% of parents reported following an alternative schedule26
and 89% of physicians reported at least 1 request from parents to spread out vaccines in a typical month.27
This suggests the need for more-comprehensive studies of the use of ACISs for children throughout the nation, as well as investigations into the safety, efficacy, and potential consequences of delaying immunizations.
Second, our findings illustrate reasonable judgments by pediatricians who are faced with a parent who requests an ACIS. Pediatricians must navigate a course that ultimately respects parental authority and decision-making but strives to protect the health of the child and to maintain a therapeutic alliance with the parent. According to our study, pediatricians seem to consider parents' requests for ACISs by generally conceding strict adherence to the recommended immunization schedule but remaining firm in their recommendations for a few vaccines (Hib vaccine, DTaP vaccine, and PCV). By doing so, pediatricians are working to protect the child from diseases that are still common (eg, pertussis) or that are more likely to have severe sequelae in infancy and early childhood (eg, Hib or pneumococcal meningitis), while respecting parental wishes to follow an ACIS.
Third, our findings suggest a need for flexibility in addressing parental immunization requests. One potential approach would be to take advantage of the inherent flexibility in the ACIP schedule for each vaccine dose, denoted by the window in the schedule that reflects the acceptable time period during which that dose can be given. For example, at 2 months of age, there is a 4-week period during which the first doses of DTaP vaccine, Hib vaccine, IPV vaccine, and PCV may be administered.21
Strict adherence to the ACIP recommended schedule would call for simultaneous administration of these 4 doses at a single visit; however, if the 4 doses were spaced out but still administered within the recommended 4-week period (eg, 2 at the beginning of the interval and 2 at the end of the interval), this would remain compatible with the ACIP schedule and might alleviate some parental immunization concerns (albeit at increased cost).
Although a strategy such as this might be appropriate and helpful, it likely would not be sufficient to address all parental immunization concerns. To this end, the results of our study suggest that there is a need for supporting pediatrician judgment regarding how best to administer all recommended vaccines to children whose parents request an ACIS. At a minimum, evidence of frequent parental requests for ACISs and the approaches of pediatricians who accommodate those requests demonstrate the need for policymakers to consider the challenges faced by primary care clinicians in implementing the recommended immunization schedule. Additional research is needed to elucidate the potential population-level effects of ACISs.
Our study has a number of limitations. Inherent in any survey is the possibility of response bias, which may affect results. Because our results were based on data from a subsample of Washington State pediatricians who completed the survey, the results may not be generalizable to all pediatricians in Washington State, pediatricians in other states, or other types of childhood immunization providers, including family physicians, physician assistants, and nurse practitioners. However, our finding that 61% of responding pediatricians were comfortable using ACISs if asked is similar to the results of a recent national survey in which 64% of responding pediatricians and family physicians would agree to spread out vaccines in the primary series at least sometimes.27
An additional limitation of our survey is that we were unable to differentiate providers who were comfortable with ACISs because they thought ACISs were as effective as or superior to the existing recommendations from those who have become comfortable with ACISs because parents of their patients are unwilling to agree to the ACIP-recommended schedule. However, our results clearly show that pediatricians' comfort using ACISs if requested is not associated with the belief that there are too many immunizations per visit or overall, and an overwhelming majority would follow the ACIP-recommended schedule if they were to become new parents in 2010.