Table.

Cumulative incidence per 100 000 population of probable meningococcal meningitis by age category reported through Maladies Potentiel Épidémie surveillance during weeks 1–37 in Burkina Faso, 2007–11

	Cumulative incidence (n)					Baselineyear*	2011 compared to baselineyear
	2007	2008	2009	2010	2011		CIR (95%CI)	p value	Relative risk reduction†
Age (years)
<1	26.9 (167)	14.4 (92)	6.3 (42)	4.4 (30)	2.0 (14)	2010	0.46 (0.24–0.86)	0.02	54%
1–4	30.6 (652)	14.2 (312)	3.6 (83)	6.0 (140)	1.5 (37)	2009	0.43 (0.29–0.63)	<0.0001	57%
5–4	32.6 (1339)	15.3 (649)	5.5 (243)	10.9 (492)	2.0 (92)	2009	0.36 (0.29–0.46)	<0.0001	64%
15–29	11.6 (417)	5.3 (195)	1.9 (72)	1.8 (71)	0.7 (28)	2010	0.39 (0.25–0.6)	<0.0001	61%
≥30	4.8 (185)	3.3 (132)	0.7 (30)	0.6 (24)	0.3 (11)	2010	0.45 (0.22–0.91)	0.003	55%
Total (1–29)	24.4 (2408)	11.4 (1156)	3.8 (398)	6.5 (703)	1.4 (157)	2009	0.38 (0.31–0.45)	<0.0001	62%
Total (<1, ≥30)	7.8 (352)	4.8 (224)	1.5 (72)	1.1 (54)	0.5 (25)	2010	0.45 (0.28–0.73)	0.001	55%

CIR=cumulative incidence ratio.

^*The year with the lowest incidence before implementation was used as the baseline year for comparison to 2011.

^†Relative risk reduction indicates a decrease in risk of meningitis in the aff ected population relative to the baseline after vaccine introduction calculated as (1–CIR)×100.