Deficiencies in current childhood immunization indicators.
OBJECTIVE
To investigate "up-to-date" and "age-appropriate" indicators of preschool vaccination status and their implications for vaccination policy.


METHODS
The authors analyzed medical records data from the Baltimore Immunization Study for 525 2-year-olds born from August 1988 through March 1989 to mothers living in low-income Census tracts of the city of Baltimore.


RESULTS
While only 54% of 24-month-old children were up-to-date for the primary series, indicators of up-to-date coverage were consistently higher, by 37 or more percentage points, than corresponding age-appropriate indicators. Almost 80% of children who failed to receive the first dose of DTP or OPV age-appropriately failed to be up-to-date by 24 months of age for the primary series.


CONCLUSIONS
Age-appropriate immunization indicators more accurately reflect adequacy of protection for preschoolers than up-to-date indicators at both the individual and population levels. Age-appropriate receipt of the first dose of DTP should be monitored to identify children likely to be underimmunized. Age-appropriate indicators should also be incorporated as vaccination coverage estimators in population-based surveys and as quality of care indicators for managed care organizations. These changes would require accurate dates for each vaccination and support the need to develop population-based registries.
Bolton
P
P
Johns Hopkins School of Hygiene and Public Health, Baltimore, MD 21205, USA.
Hussain
A
A
Hadpawat
A
A
Holt
E
E
Hughart
N
N
Guyer
B
B
D015142:Baltimore; D002675:Child, Preschool; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage; D006801:Humans; D007115:Immunization Schedule; D008458:Measles Vaccine / Q000008:administration & dosage; D022542:Measles-Mumps-Rubella Vaccine; D008499:Medical Records; D009108:Mumps Vaccine / Q000008:administration & dosage; D011054:Poliovirus Vaccine, Inactivated / Q000008:administration & dosage; D011159:Population Surveillance / Q000379:methods*; D011203:Poverty; D011237:Predictive Value of Tests; D012411:Rubella Vaccine / Q000008:administration & dosage; D014611:Vaccination / Q000706:statistics & numerical data*; D017778:Vaccines, Combined / Q000008:administration & dosage
D015721:Diphtheria-Tetanus-Pertussis Vaccine; D008458:Measles Vaccine; D022542:Measles-Mumps-Rubella Vaccine; D009108:Mumps Vaccine; D011054:Poliovirus Vaccine, Inactivated; D012411:Rubella Vaccine; D017778:Vaccines, Combined