Do Piperonyl Butoxide Long-Lasting Insecticide Treated Nets Provide Additional Protection Against Malaria Infections Compared with Conventional Netsin an Operational Setting in Western Kenya?

Sep 30, 2026

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Malaria control across sub-Saharan Africa has slowed despite broad adoption of long-lasting insecticidal nets (LLINs). Progress has been hindered in part by pyrethroid insecticide resistance, prompting use of retooled nets incorporating the synergist piperonyl butoxide (PBO). This cohort study in Bungoma County, Western Kenya followed 768 participants from June 2017 to December 2023 using active and passive surveillance with monthly LLIN-use recording and RDT-confirmed symptomatic cases, comparing PBO versus conventional LLIN protection against malaria infections. Multilevel logistic regression of monthly RDT outcomes showed higher individual-level protection with PBO LLINs (odds ratio 0.70; 95% CI 0.47–1.03), though results were not statistically significant.

LanguageEnglish

CategoryHealthcare

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Pages11

Reading Time28 min

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Abstract

Introduction

Long-lasting insecticidal nets as the malaria prevention cornerstone

Plateauing malaria control and contributing challenges

Pyrethroid resistance and next-generation LLIN strategies

Am. J. Trop. Med. Hyg., 114(1), 2026, pp. 123–133 doi:10.4269/ajtmh.25-0211 Copyright © 2026 The author(s) Do Piperonyl Butoxide Long-Lasting Insecticide Treated Nets Provide Additional Protection Against Malaria Infections Compared with Conventional Netsin an Operational Setting in Western Kenya? Karla Rascn-Garca,1 Zena Lapp,1 Christine F. Markwalter,1 Emmah Kimachas,2 Lucy Abel,2 Andrew Obala,2,3 Steve M. Taylor,1,4 Wendy Prudhomme O’Meara,1,4,5 and Judith Nekesa Mangeni2,5* 1Duke Global Health Institute, Duke University, Durham, North Carolina; 2Academic Model Providing Access to Health Care, Eldoret, Kenya; 3School of Medicine, College of Health Sciences, Moi University, Eldoret, Kenya; 4Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina; 5School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya Abstract. Malaria control in sub-Saharan Africa has stagnated despite widespread adoption of control measures such as long-lasting insecticidal nets (LLINs) . Progress has stalled, in part, because of pyrethroid insecticide resistance, driving the need for retooling to increase the effectiveness of bed nets. Consequently, LLINs have been treated with the chemical synergist piperonyl butoxide (PBO) . Piperonyl butoxide LLINs have been shown to be efficacious in controlled settings; however, their effectiveness in real-world settings warrants investigation. In Bungoma County, Western Kenya, a cohort of 768 participants was followed from June 2017 to December 2023 via active and passive surveillance. Household visits were conducted monthly, during which LLIN use for nets distributed in 2017 and 2021 was recorded, and symptomatic malaria cases were identified using rapid diagnostic tests (RDTs) . The comparative effectiveness of PBO versus conventional LLINs was assessed in terms of malaria infections. A multilevel logistic regression model was fit with monthly RDT results as the dependent variable. The study results indicate that PBO LLINs provide greater protection against malaria at the individual level than conventional LLINs (odds ratio: 0.70; 95% CI: 0.47– 1.03), although the findings were not statistically significant. The added protection against malaria infections provided by PBO LLINs compared with conventional LLINs observed in the current study aligns with findings from most previous studies, although this finding was not statistically significant. In areas with documented pyrethroid resistance, the use of LLINs with an added synergist, such as PBO, can provide additional protection against malaria infections (compared with pyrethroid-only LLINs) and should be considered for scaled-up scenarios despite the additional cost. INTRODUCTION Long-lasting insecticidal nets (LLINs) are the cornerstone of malaria prevention efforts across sub-Saharan Africa. Since 2004, more than 2 billion LLINs have been distributed globally.1 ,2 As a result, household ownership of LLINs in sub-Saharan Africa rose from 5% to a peak of 75% by 2017,3 contributing to a more than 40% decline in malaria incidence and deaths across the continent.1 ,2 However, since 2015, global malaria cases have plateaued, with some regions experiencing resurgence, including areas where control efforts had previously been successful.4–6 Malaria control has plateaued for several reasons, including stagnating financial support. In 2018, for example, there was a funding gap of 􀀘 5.0 billion US dollars compared with the estimated global amount necessary to maintain progress toward malaria control targets.3 , 7 ,8 The situation is further complicated by the spread of vector resistance to pyrethroid insecticides, which has likely contributed to a resurgence of malaria in some regions.2,3,6,9 Pyrethroids have traditionally been used to impregnate bed nets owing to their favorable safety profile, relatively lower cost, and rapid insecticidal activity against mosquitoes with minimal harm to huma

FAQs

Why were piperonyl butoxide (PBO) long-lasting insecticidal nets introduced?

Because pyrethroid resistance has reduced the effectiveness of conventional LLINs, retooling is needed to improve bed-net performance. PBO acts as a synergist to enhance insecticide effectiveness.

How was effectiveness of PBO nets compared with conventional LLINs in this study?

A cohort of 768 participants in Western Kenya was followed from June 2017 to December 2023. Household visits recorded LLIN use and symptomatic malaria cases were identified using rapid diagnostic tests (RDTs), then multilevel logistic regression assessed malaria infection outcomes.

Did PBO LLINs show a statistically significant advantage over conventional nets?

PBO LLINs provided greater individual-level protection against malaria infections than conventional LLINs, but the reported findings were not statistically significant.

Sep 30, 2026

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