Table 3.

Incidence rates and ratios of Plasmodium falciparum infection among control and intervention groups in Largo and Tobanda camps, estimated from the random effects Poisson regression model^*

	Number enrolled	Total child days at risk	Average number of days at risk	IR (95% CI)	IRR (95% CI)	% PE (95% CI)	Wald test P value	Adjusted IRR† (95% CI)	Adjusted % PE† (95% CI)	Wald test P value
Largo
UPS	49	6801	139	163 (157–169)	1	–		1	–
ITPS	51	8459	166	63 (52–76)	0.39 (0.36–0.41)	61 (59–63)	< 0.001	0.40 (0.33–0.47)	60 (53–67)	< 0.001
Tobanda
UPS	67	9102	136	157 (147–167)	1	–		1	–
ITPS	55	6661	121	133 (120–148)	0.85 (0.81–0.89)	15 (11–19)	0.008	0.85 (0.75–0.95)	15 (5–25)	0.008

^*IR = incidence rate per 100 child-years at risk; IRR = incidence rate ratio; PE = protective efficacy; UPS = polyethylene sheeting; ITPS = insecticide-treated plastic sheeting; CI = confidence interval.

^†Adjusted for age and sex.