Is there a correlation between malaria incidence and IRS coverage in western Zambezi region, Namibia?

Setting: A comparison of routine Namibia National Malaria Programme data (reported) vs. household survey data (administrative) on indoor residual spraying (IRS) in western Zambezi region, Namibia, for the 2014-2015 malaria season. Objectives: To determine 1) IRS coverage (administrative and reported), 2) its effect on malaria incidence, and 3) reasons for non-uptake of IRS in western Zambezi region, Namibia, for the 2014-2015 malaria season. Design: This was a descriptive study. Results: IRS coverage in western Zambezi region was low, ranging from 42.3% to 52.2% for administrative coverage vs. 45.9-66.7% for reported coverage. There was no significant correlation between IRS coverage and malaria incidence for this region (r = -0.45, P = 0.22). The main reasons for households not being sprayed were that residents were not at home during spraying times or that spray operators did not visit the households. Conclusions: IRS coverage in western Zambezi region, Namibia, was low during the 2014-2015 malaria season because of poor community engagement and awareness of times for spray operations within communities. Higher IRS coverage could be achieved through improved community engagement. Better targeting of the highest risk areas by the use of malaria surveillance will be required to mitigate malaria transmission.