Fig. 3.

Modelled estimates of the impact on malaria of changing the timing of the mass LLIN campaign in 2020–21 caused by the COVID-19 pandemic. In A, the population size in each sub-district varied, with most people residing in the sub-districts where net distributions were delayed compared to those distributed early relative to the schedule prior to interruptions from the pandemic (numbers of sub-districts in each category shown). The transmission model simulated all-age clinical incidence daily so that it was possible to compare 2019–2023 impacts given the scheduled, or delivered mass campaign. B Illustrates this for the Buliisa health sub-district which was scheduled to receive LLINs in Nov-Dec 2020 (red simulation), but received the nets in August 2020 (green). The polygons mark the years for comparison. In C, the model-estimated clinical cases per 1,000 people were calculated across the 4 years from January 2019 for clusters (individual points), according to whether nets were delivered before or after the scheduled time. D Shows the estimated total number of cases in the region (thousands of cases) for each year, given the schedule or the actual campaign dates across the 100 clusters