<p>The average monthly malaria incidence during three months before IRS during 2016-2020 was 4.2/1,000 vs 0.8/1,000 during the three months after IRS. The average monthly incidence during the three months before IRS in 2021 was 3.6/1,000, versus 3.9/1,000 after IRS. Interviewees reported proper storage during transport to district stores and at the stores, use of IRS-experienced teams to conduct the 2021 IRS, and four-day trainings on IRS use with practical sessions on chemical mixing, storage, spraying, and quality assurance at every stage. Morning spraying ‘drills’ were done with IRS operators at the start of each IRS day. Teams were supervised by expert staff in IRS.</p>