Monitoring the durability of the long-lasting insecticidal nets Olyset ® and PermaNet ® 2.0 in similar use environments in Zanzibar

• Published in: Malaria journal 2020-05, Vol.19 (1), p.187-187, Article 187
• Main Authors: Haji, Khamis Ameir, Khatib, Bakari Omar, Obi, Emmanuel, Dimoso, Kanuth, Koenker, Hannah, Babalola, Stella, Greer, George, Serbantez, Naomi, Abbas, Faiza, Ali, Abdullah, Blaufuss, Sean, Olapeju, Bolanle, Kilian, Albert
• Format: Article
• Language: English
• Subjects: Analysis; Artemisinin; Cohorts; Disease eradication; Disease Eradication - statistics & numerical data; Disease transmission; Durability; Households; Human diseases; Humans; Insecticide-Treated Bednets - statistics & numerical data; Insecticides; LLIN; Malaria; Malaria - prevention & control; Marketing; Monitoring; Mosquito Control - statistics & numerical data; Nets; Prospective Studies; Questionnaires; Survival; Tanzania; Toughness; Vector-borne diseases; Zanzibar
• ISSN: 1475-2875; 1475-2875
• DOI: 10.1186/s12936-020-03258-w

Malaria transmission in Zanzibar has dramatically reduced in recent years but vector control interventions such as long-lasting insecticidal nets (LLIN) must continue to reach malaria elimination. To achieve this, the Zanzibar Malaria Elimination Programme needs actionable evidence of the durability of the LLIN brands distributed. This study compared physical and insecticidal durability of two LLIN brands: Olyset and PermaNet© 2.0 in two similar districts on the islands of Unguja and Pemba. This was a prospective cohort study of representative samples of households from two districts, recruited at baseline 4 months after the mass campaign. All campaign nets in these households were labelled and followed up over a period of 33 months. Primary outcome was the "proportion of nets surviving in serviceable condition" based on attrition and integrity measures and the median survival in years. The outcome for insecticidal durability was determined by bio-assay from sub-samples of campaign nets. A total of 834 campaign nets (121% of target) from 299 households were included in the study. Definite outcomes could be determined for 86% of the cohort nets in Unguja (PermaNet 2.0) and 89% in Pemba (Olyset ). After 33 months, physical survival in serviceable condition was 55% in Unguja and 51% in Pemba. Estimated median survival was lower in Pemba at all time points with 2.3-2.7 years compared to 3.1-3.3 yeas in Unguja. Multivariable Cox proportionate hazard models confirmed the difference between brands (p