The effect of neonatal bacille Calmette-Guérin vaccination on purified protein derivative skin test results in Canadian aboriginal children.
BACKGROUND
The effect that neonatal bacille Calmette-Guérin (BCG) vaccination has on tuberculin skin test (TST) results is not well evaluated in preschool children.


METHODS
This was a retrospective cohort study of TST results in aboriginal children in Saskatchewan reserve communities. Records from the centralized provincial tuberculosis program were searched for aboriginal children aged 0 to 4 years during the time period 1991 to 1999. Only the first TST result reported as part of infant and preschool screening programs was considered. Children with active tuberculosis and those evaluated as part of a contact-tracing program were excluded. The BCG-vaccinated and unvaccinated groups were compared using wheal size cut points of 5 mm, 10 mm, and 15 mm.


RESULTS
Data from 1,086 children with neonatal BCG vaccination and 1,867 unvaccinated children were analyzed. The rate of TST reactions was higher in vaccinated children at all ages, using a cut point of 5 mm. The rate of TST reactions was no different in vaccinated children >or= 1 year old when using a cut point of 15 mm. When using a cut point of 10 mm, the rate of TST reactions was higher at age 1 year but not different at age 4 years in the vaccinated children.


CONCLUSIONS
The rate of TST reactions in preschool aboriginal children living on a reserve who have received neonatal BCG vaccination is affected by the cut point and age. The BCG vaccination status and age should therefore be considered when interpreting TST reactivity in the clinical assessment of aboriginal children participating in a tuberculosis control program.
Reid
John K
JK
Department of Medicine, University of Saskatchewan, 5th Floor Ellis Hall, 103 Hospital Dr, Saskatoon, SK, S7N 0W8, Canada. jkr647@usask.ca
Ward
Heather
H
Marciniuk
Darcy
D
Hudson
Shauna
S
Smith
Pamela
P
Hoeppner
Vernon
V
D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000367:Age Factors; D001500:BCG Vaccine / Q000627:therapeutic use*; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007198:Indians, North American; D007223:Infant; D008297:Male; D012016:Reference Values; D012189:Retrospective Studies; D012525:Saskatchewan; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000208:ethnology / Q000517:prevention & control*
D000276:Adjuvants, Immunologic; D001500:BCG Vaccine