The Immunization Delivery Effectiveness Assessment Score: A Better
Immunization Measure?
James H. Glauber, MD, MPH
From the Neighborhood Health Plan, Boston, Massachusetts
Background. Childhood immunization measures, such as the
HealthEmployer Data Information Set (HEDIS) or the National
ImmunizationSurvey, assess the percentage of children up-to-date for
a specifiedseries of vaccinations. In particular, the HEDIS assesses
immunizationdelivery to children enrolled in managed care
organizations(MCO). Such measures do not assess the timeliness of
immunizationdelivery with reference to recommended age standards. To
achievemaximal protection against vaccine-preventable diseases,
childrenshould receive all immunizations within recommended age
intervalsfully"on-time."
Objective. The Immunization Delivery Effectiveness Assessment(IDEA) is a novel immunization measure that assesses, on a continuousscale, the timeliness of administration of each vaccination
with reference to recommended age intervals. Specifically weask: 1)
Do absolute immunization rates differ between HEDISand IDEA? 2) Does
relative MCO performance differ when assessedby the 2 performance
measures? 3) How well do MCOs perform relativeto the standard of
fully on-time immunization? The health servicesimplications of using
the timeliness standard to assess childhoodimmunization delivery is
discussed.
Methods. A vaccine-dose IDEA score was developed for each ofthe 14 vaccination events in the 4:3:1:3:3 combination series
(4 diphtheria-pertussis-tetanus:3 polio:1 measles-mumps-rubella:3
Haemophilus influenzae type B:3 hepatitis B). Assessing the
actual age of administration with reference to the recommendedage of
administration generates the vaccine-dose IDEA score.A childs
composite IDEA score is obtained by averagingthe 14 vaccine-dose
IDEA scores. These composite IDEA scores,when averaged among
children sampled within the MCO, constitutethe MCOs immunization
score.
Setting. Retrospective analysis of childhood immunization datasetsfrom a convenience sample of 6 MCOs in 5 states.
Results. HEDIS rates ranged from 57% to 75%. IDEA scores rangedfrom 80% to 90%. Relative rankings of MCO immunization performancewere different using HEDIS rates and IDEA scores, respectively.
At most, 16% of children in any of these MCOs received all oftheir
immunizations fully on-time. From 47% to 77% of childrenexperienced
at least 3 delayed immunizations.
Conclusions. An immunization measure based on timeliness of
administration yields both absolute and relative differencesin MCO
childhood immunization performance when compared withHEDIS rates. By
assessing delivery of each component vaccination,the IDEA score
permits more detailed analysis of immunizationpatterns within an MCO
and focuses improvement efforts.
Key Words: immunization measurement quality managed
care
Abbreviations: HEDIS, Health Employer Data Information Set
MCO, managed care organization IDEA, Immunization Delivery Effectiveness
Assessment VPD, vaccine-preventable disease NIS, National Immunization
Survey DPT, diphtheria-pertussis-tetanus MMR, measles-mumps-rubella HIB,
Haemophilus influenzae type B HBV, hepatitis B AAP, American Academy
of Pediatrics ACIP, Advisory Committee on Immunization Practice a-AOA,
actual age-of-administration DOL, days-of-life L-AOA, latest acceptable age
of administration
Received for publication Jun 12, 2002; accepted Feb 27, 2003.
DISCLAIMER:
All information, data, and material contained, presented, or provided here
is for general information purposes only and is not to be construed as
reflecting the knowledge or opinions of the publisher, and is not to be
construed or intended as providing medical or legal advice. The decision
whether or not to vaccinate is an important and complex issue and should
be made by you, and you alone, in consultation with your health care
provider.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"