Bed nets coated with a long-lasting chemical called piperonyl butoxide (PBO) combined with pyrethroid insecticide reduced the prevalence of malaria in children by 44% over one year, and 33% over two years, compared to the bed nets currently used, according to a randomised controlled trial published in The Lancet.

Based on this evidence, the World Health Organisation (WHO) recommends increasing coverage of PBO bed nets in areas where resistance to pyrethroids is developing.

Progress in malaria control is under threat by wide-scale resistance to the pyrethroid insecticide class currently used in indoor spraying and on current bed nets. This has resulted in a need for new types of insecticide for nets and indoor spraying.

Indoor spraying of walls and ceilings kills mosquitoes that enter the home, while bed nets prevent them from reaching and biting people during the night, and the insecticide coating the nets kills the mosquitoes.