Minimum time interval adjustment for 4-3-1 immunization rates among two-year-old children.
BACKGROUND
The purpose is to determine the administrative validity of the 4-3-1 immunization rates for DPT-OPV-MMR vaccines for 2-year-old children in a community health status assessment project by accounting for premature administration of specific vaccine doses according to ACIP recommended minimal timing intervals.


METHODS
A retrospective survey of immunization certificates was made on a random sample of 1,059 kindergarten enrollees in the county, including public, private, and parochial schools. The immunization rates by the crude 4-3-1 counting method were compared with the same method adjusted for minimal time interval vaccine dosing.


RESULTS
By the crude 4-3-1 counting method, 55.5% of the students had complete immunizations by their second birthdate, and 11.8% did not meet the minimum interval recommendations on at least one of 4-3-1 vaccine series. The adjustment for minimum time interval reduced the percent in compliance with the 4-3-1 counting method by age 2 in the community to 50.7%.


CONCLUSIONS
The premature timing of vaccine doses is a threat to the validity of the 4-3-1 counting method. The crude 4-3-1 method over-estimates the completed immunization rates for 2-year-olds in this community-based study by about 4.8%.
Steiner
R P
RP
Department of Family and Community Medicine, University of Louisville, Kentucky 40292, USA. npstei01@gwise.louisville.edu
Hughes
J A
JA
Richardson
T L
TL
Looney
S W
SW
Clover
R D
RD
Rowe
M G
MG
D002675:Child, Preschool; D003625:Data Collection; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage*; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D007629:Kentucky; D008297:Male; D008458:Measles Vaccine / Q000008:administration & dosage*; D022542:Measles-Mumps-Rubella Vaccine; D009108:Mumps Vaccine / Q000008:administration & dosage*; D011055:Poliovirus Vaccine, Oral / Q000008:administration & dosage*; D012189:Retrospective Studies; D012411:Rubella Vaccine / Q000008:administration & dosage*; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; 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; D011055:Poliovirus Vaccine, Oral; D012411:Rubella Vaccine; D017778:Vaccines, Combined