KEYWORD1:
Immunization schedule, missed opportunities

BACKGROUND:
In the past five years, the total number of injections required in the immunization schedule has doubled. Little is known of the impact of these changes on missed opportunities.

OBJECTIVE:
To document trends in missed opportunities for vaccine administration relative to the increase of injections in the immunization schedule, 1996-2001.

METHOD:
From 1996 to 2001, we conducted semi-annual chart audits of 22,515 randomly selected 6-35 month olds at 26 inner city practices in New York City. We calculated quarterly missed opportunities by antigen. We tested for significant differences in missed opportunities between 1996 and 2001 for each antigen. We used correlation analysis to examine the associations between quarterly missed opportunities and the number of injections required per ACIP/APA/DOH.

RESULT:
For most but not all antigens, missed opportunities increased significantly between 1996 and 2000: Polio increased from 4.9% to 14.1% (p <.05); Hib from 3.9% to 8.9% (p <.05); and MMR from1.6% to 2.1%(p <.01). The increase in missed opportunities was associated with the increase of total number of injections required in the schedule (DTP, r = .67, p <.01; Polio, r = .56, p <.01; Hib, r = .71, p <.001; MMR, r = .66, p <.01).

CONCLUSION:
In inner city practices in New York City, the increasing complexity of immunization schedule was significantly associated with increase in missed opportunities.
LEARNINGOBJECTIVES:
To learn how changes in the immunization schedule affect missed opportunities for vaccinations.