Estimating the annual risk of infection with Mycobacterium tuberculosis among adolescents in Western Kenya in preparation for TB vaccine trials

Table 2 ARTI estimates and prevalence of infection presented for all adolescents, those with and without a BCG scar

	N	Mean age (years)	≥ 10 mm^b			Mirror method 17 mm^a
	N	Mean age (years)	P	ARTI	CI (95%)	P	ARTI^c	CI (95%)
All	4808	14.4	32.1%	2.6%	(2.2,3.1)	27.6%	2.2%	(1.8,2.6)
BCG scar	3947	14.4	33.5%	2.7%	(2.2,3.2)	27.8%	2.2%	(1.7,2.7)
BCG scar absent	859	14.2	25.6%	2.1%	(1.1,3.1)	27.0%	2.1%	(1.1,3.1)

CI 95% Confidence interval
^aThe total number of adolescents with true reactions was calculated by adding the number of adolescents showing reaction sizes equal to the mode to double the number with reaction sizes larger than the mode to determine the numerator
^bThe Cut-off for HIV+ was ≥5 mm
^cARTI formula =1-(1-prevalence of infection) ^{1/mean age}

ISSN: 1471-2334