According to one study comparing methods to prevent malaria between 2000 and 2015 in sub-Saharan Africa, the combined methods prevented approximately 663 million cases, and ITNs in particular prevented about 68 percent of those cases (around 451 million). Although ITN users are still protected by the physical barrier of the netting, non-users could experience an increased bite rate as mosquitoes are deflected away from the non-lethal bed net users. A 2025 analysis by the Malaria Atlas Project estimated that, across Africa from 2000 to 2024, malaria control interventions averted approximately 1.57 billion cases and 6.2 million deaths, with insecticide-treated mosquito nets responsible for about 72 % of all cases prevented, an increase from the 68 % reported for 2000–2015. ITNs protect the individuals or households that use them, and they protect people in the surrounding community in one of two ways. • First, ITNs kill adult mosquitoes infected with the malaria parasite directly which increases their mortality rate and can therefore decrease the frequency in which a person in the community is bitten by an infected mosquito. • Second, certain malaria parasites require days to develop in the salivary glands of the vector mosquito. This process can be accelerated or decelerated via weather; more specifically heat.
Plasmodium falciparum, for example, the parasite that is responsible for the majority of deaths in
Sub-Saharan Africa, takes eight days to mature. Therefore, malaria transmission to humans does not take place until approximately the tenth day, although it requires blood meals at intervals of two to five days. By killing mosquitoes before maturation of the malaria parasite, ITNs can reduce the number of encounters of infected mosquitoes with humans. As a result, the mosquito netting and pesticide industries developed so-called long-lasting insecticidal mosquito nets, which also use pyrethroid insecticides. There are three types of LLINs — polyester netting which has insecticide bound to the external surface of the netting fibre using a resin; polyethylene which has insecticide incorporated into the fibre and polypropylene which has insecticide incorporated into the fibre. All types can be washed at least 20 times, but physical durability will vary. A survey carried out in
Tanzania concluded that effective life of polyester nets was 2 to 3 years; with polyethylene LLINs there are data to support over 5 years of life with trials in showing nets which were still effective after 7 years.
Scientific trials A review of 22
randomized controlled trials of ITNs found (for
Plasmodium falciparum malaria) that ITNs can reduce deaths in children by one fifth and episodes of malaria by half. More specifically, in areas of stable malaria "ITNs reduced the incidence of uncomplicated malarial episodes by 50% compared to no nets, and 39% compared to untreated nets" and in areas of unstable malaria "by 62% compared to no nets and 43% compared to untreated nets". As such the review calculated that for every 1000 children protected by ITNs, 5.5 lives would be saved each year. Through the years 1999 and 2010 the abundance of female anopheles gambiae densities in houses throughout western Kenya were recorded. This data set was paired with the spatial data of bed net usage in order to determine correlation. Results showed that from 2008 to 2010 the relative population density of the female anopheles gambiae decreased from 90.6% to 60.7%. The conclusion of this study showed that as the number of houses which used insecticide treated bed nets increased the population density of female anopheles gambiae decreased. This result did however vary from region to region based on the local environment. A 2019 study in
PLoS ONE found that a campaign to distribute mosquito bednets in the Democratic Republic of Congo led to a 41% decline mortality for children under five who lived in areas with a high malaria risk. ==Associated problems==