Fig. 5

Average level of control over the 12 year duration of the simulation for LLINs with a pyrethroid and a different partner insecticide (NEW  New AI 1 or 2, PPF  Pyriproxyfen, CHL Chlorfenapyr, PBO Piperonyl butoxide, and – = No partner, i.e. the solo-use of pyrethroid) under different optimality criteria as labelled: A the baseline where both insecticides are used at their solo loadings (BL), B the cheapest bed net that satisfies the WHO requirements (CW; under the relaxed criterion that permits pyrethroids to be tested against a susceptible population, as the WHO currently allows), and C the global optimum that maximizes the vector control (MC). Note that neither pyrethroid-chlorfenapyr nor the solo-pyrethroid LLINs strictly passed the WHO standard of > 80% efficacy after 3 years, so the CW optimum finds no solution for these bed nets; in practical terms, the WHO permits a pyrethroid to be tested against a pyrethroid-susceptible population, which would alter this optimum for all LLINs to favour a solo-pyrethroid LLIN (of loading 1.1) that would produce a control profile that is approximately ¼ of the profile in Fig. 4B