Table 2.

Multivariate incidence rate ratios (IRR) for all-ages laboratory-confirmed uncomplicated malaria cases reported through routine surveillance, adjusted for estimated catchment population in the Boucle du Mouhoun 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	1.138	0.931	1.392	0.207	1.178	0.970	1.431	0.098	1.159	0.947	1.418	0.152
IRS districts
Pre-intervention monthly trend in population-adjusted all-ages malaria casesa	0.974	0.969	0.979	< 0.001**	0.979	0.974	0.984	< 0.001**	0.978	0.973	0.983	< 0.001**
Post-intervention change in monthly trend of population-adjusted all-ages malaria casesb	0.933	0.923	0.944	< 0.001**	0.958	0.943	0.973	< 0.001**	0.932	0.916	0.949	< 0.001**
Post-intervention change in level of population-adjusted all-ages malaria casesb	1.942	1.746	2.160	< 0.001**	0.908	0.786	1.049	0.192	1.222	1.059	1.410	0.006*
Control districts
Pre-intervention monthly trend in population-adjusted all-ages malaria casesa	0.972	0.965	0.979	< 0.001**	0.982	0.970	0.993	0.002	0.981	0.972	0.990	< 0.001**
Post-intervention change in monthly trend of population-adjusted all-ages malaria casesb	0.924	0.898	0.951	< 0.001**	0.974	0.950	0.997	0.029*	0.900	0.868	0.933	< 0.001**
Post-intervention change in level of population-adjusted all-ages malaria casesb	2.844	2.429	3.330	< 0.001**	1.092	0.971	1.229	0.140	1.416	1.199	1.671	< 0.001**
Difference between IRS and control districts
Pre-intervention difference in monthly trend of population-adjusted all-ages malaria casesa	1.002	0.993	1.011	0.627	0.997	0.984	1.010	0.653	0.997	0.987	1.007	0.576
Post-intervention difference in change in monthly trend of population-adjusted all-ages malaria casesb	1.010	0.978	1.042	0.545	0.984	0.955	1.014	0.292	1.036	0.994	1.079	0.095
Post-intervention difference in change in level of population-adjusted all-ages malaria casesb	0.683	0.564	0.827	< 0.001**	0.831	0.687	1.006	0.057	0.863	0.698	1.069	0.177
Control variables
Rainfall (lagged 2 months), per 10 mm	1.000	0.947	1.057	0.988	0.933	0.865	1.007	0.074	1.050	1.001	1.102	0.045*
EVI (lagged 1 month)	1.258	1.189	1.332	< 0.001**	1.459	1.344	1.585	< 0.001**	1.284	1.214	1.358	< 0.001**
High season (binary)	0.858	0.831	0.885	< 0.001**	0.817	0.794	0.840	< 0.001**	0.854	0.831	0.878	< 0.001**
Observations	1.990				2.052				2.048
Number of health facilities	59				59				59

*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