Table 3.

Multivariate incidence rate ratios (IRR) for all-ages laboratory-confirmed uncomplicated malaria cases reported through routine surveillance, adjusted for estimated catchment population in the Sud-Ouest region

	2018 IRS				2020 IRS				2021 IRS
	IRR	95% CI		P	IRR	95% CI		P	IRR	95% CI		P
		Lower	Upper			Lower	Upper			Lower	Upper
IRS exposure
Unsprayed districts	Ref				Ref				Ref
Sprayed districts	1.108	0.716	1.713	0.645	1.095	0.709	1.690	0.683	1.092	0.715	1.670	0.683
IRS districts
Pre-intervention monthly trend in population-adjusted all-ages malaria casesa	1.002	0.981	1.024	0.840	1.005	0.980	1.030	0.700	1.003	0.980	1.026	0.829
Post-intervention change in monthly trend of population-adjusted all-ages malaria casesb	0.945	0.918	0.973	< 0.001**	0.979	0.947	1.013	0.218	1.027	0.973	1.084	0.331
Post-intervention change in level of population-adjusted all-ages malaria casesb	0.916	0.849	0.978	0.022*	0.872	0.627	1.212	0.415	0.763	0.532	1.095	0.142
Control districts
Pre-intervention monthly trend in population-adjusted all-ages malaria casesa	0.983	0.977	0.990	< 0.001**	0.985	0.979	0.991	< 0.001**	0.986	0.980	0.992	< 0.001**
Post-intervention change in monthly trend of population-adjusted all-ages malaria casesb	0.947	0.932	0.963	< 0.001**	0.963	0.947	0.980	< 0.001**	1.008	0.998	1.019	0.126
Post-intervention change in level of population-adjusted all-ages malaria casesb	1.434	1.231	1.670	< 0.001**	1.366	1.174	1.590	< 0.001**	1.232	1.065	1.425	0.005*
Difference between IRS and control districts
Pre-intervention difference in monthly trend of population-adjusted all-ages malaria casesa	1.019	0.997	1.042	0.098	1.020	0.994	1.047	0.136	1.017	0.993	1.042	0.174
Post-intervention difference in change in monthly trend of population-adjusted all-ages malaria casesb	0.998	0.965	1.031	0.891	1.016	0.979	1.055	0.397	1.019	0.964	1.076	0.508
Post-intervention difference in change in level of population-adjusted all-ages malaria casesb	0.639	0.537	0.760	< 0.001**	0.638	0.441	0.924	0.017*	0.619	0.418	0.918	0.017*
Control variables
Rainfall (lagged 2 months), per 10 mm	1.058	1.013	1.104	0.010*	1.053	1.021	1.086	0.001*	1.034	1.004	1.065	0.025*
EVI (lagged 1 month)	1.055	0.999	1.113	0.052	1.132	1.084	1.183	< 0.001**	1.255	1.194	1.320	< 0.001**
High season (binary)	0.954	0.909	1.002	0.061	0.962	0.919	1.007	0.097	0.873	0.832	0.916	< 0.001**
Observations	1.082				1.107				1.115
Number of health facilities	32				32				32

*P < 0.05; **P < 0.001

^aThe baseline period comprises July 2016 to June 2018

^bThe post-IRS period comprises July 2018 to May 2019 for the 2018 IRS evaluation; July 2020 to June 2021 for the 2020 IRS evaluation; and July 2021 to June 2022 for the 2021 IRS evaluation