Immunisation coverage of Queensland indigenous two-year-old children by cluster sampling and by register.
OBJECTIVE
To obtain, through a survey, estimates of immunisation coverage in a birth cohort of Indigenous children, and to compare survey estimates with those obtained from the Australian Childhood Immunisation Register (ACIR) for the same birth cohort of Indigenous children.


METHODS
Cluster sampling of a birth cohort of two-year-old Indigenous children across Queensland, stratified according to accessibility/remoteness from services, was undertaken in 2003. An innovative method of identifying participants was used. Survey results of 10 vaccine doses were compared with ACIR data.


RESULTS
The survey obtained a 4% sample of the birth cohort (137 children). Universally recommended vaccines showed high levels of coverage at 12 and 24 months, and survey estimates were slightly higher than ACIR estimates. Diphtheria-tetanus-acellular pertussis vaccine dose 3 (DTPa3) coverage was 93.8% (95% CI 88.0-99.6) by 12 months on survey and 87.5% on ACIR. Coverage was not timely and a lag phase of 4-6 months occurred for each vaccine dose. Haemophilus influenzae type b vaccine dose 2 (Hib2), scheduled for the age of four months, reached 90% coverage by nine months of age in the survey children.


CONCLUSIONS
Both methods reported here provided similar results.


CONCLUSIONS
These data indicate that ACIR Indigenous reporting rates have increased and coverage estimates are comparable to those provided by a survey. Immunisation coverage appears to be high, and the main remaining challenge in further reducing vaccine-preventable disease in Indigenous children is to improve immunisation timeliness.
Vlack
Susan
S
School of Population Health, University of Queensland. s.vlack@uq.edu.au
Foster
Rosemary
R
Menzies
Robert
R
Williams
Gail
G
Shannon
Cindy
C
Riley
Ian
I
D002675:Child, Preschool; D016000:Cluster Analysis; D015331:Cohort Studies; D005260:Female; D019538:Health Care Surveys; D006303:Health Services, Indigenous; D006801:Humans; D017589:Immunization Programs / Q000379:methods / Q000706:statistics & numerical data*; D008297:Male; D008507:Medically Underserved Area; D011793:Queensland; D012042:Registries; D014611:Vaccination / Q000706:statistics & numerical data*