Acceptability and preferences for dual-active ingredient long-lasting insecticidal nets in rural Tanzania: a...

The World Health Organization (WHO) recommends dual-active ingredient long-lasting insecticidal nets (dual-AI LLINs) for protection against malaria in areas with insecticide resistance. The effectiveness of LLINs, however, depends on user compliance, influenced by community perceptions of malaria, prevention methods, and the acceptability of LLINs. Understanding these factors is essential for the success of large-scale implementation.

This study was part of the two cluster-randomized controlled trials (RCTs) evaluating the efficacy of dual-AI LLINs on malaria indicators in Muleba and Misungwi districts, Tanzania. Polyethylene and polyester rectangular LLINs were distributed in Muleba (Olyset Plus and Olyset Net) in 2015 and in Misungwi (Olyset Plus, Royal Guard, Interceptor G2, and Interceptor) in 2019. A mixed-methods approach was used to assess users' acceptability, preferences, and perceptions, and identifying barriers to consistent use. Quantitative data were collected from 14,475 households, while qualitative data came from 36 focus group discussions and 44 in-depth interviews. A thematic analysis was applied using a deductive approach, guided by the study's conceptual framework. Descriptive statistics were used for quantitative analysis.

LLIN usage and acceptability were influenced by their availability in the households, the physical integrity, side-effects, nuisance from mosquito bites and perceived malaria risk. Olyset Plus was slightly favoured over Olyset net in Muleba due to the perception that the insecticide had a stronger effect (72% vs 63%), p = 0.1395. In Misungwi, net acceptability, measured by the proportion reporting LLINs as no longer protective, varied significantly by net type at 24, 30, and 36 months (p < 0.0001). In Misungwi, Olyset Plus had the highest overall dissatisfaction (15.1%), followed by Royal Guard (12.0%) while Interceptor G2 and Interceptor had the lowest (7.0-7.6%). In Misungwi, 86% (2338/2736) preferred polyester nets over polyethylene due to better comfort and durability. Adverse effects (itching, skin irritation) were reported more frequently for Royal Guard and Interceptor (48-55%). Bed bug infestations were found in 19-29% of study nets, averaging 15 bugs/net, negatively influenced consistent use. LLIN repurposing was more common in Misungwi (35%) than Muleba (19%). Preferences skewed heavily toward blue (61% in Muleba vs 93% in Misungwi), rectangular LLINs (61% in Muleba vs 91% in Misungwi) in both sites.

Acceptability and sustained use of dual-AI LLINs are shaped by perceived efficacy, comfort, and net integrity, while barriers like bed bugs and skin irritation reduce use. Addressing non-target pest issues, targeting different groups of users with tailored education, and integrating user perception into LLIN procurement can enhance uptake and impact. It is recommended that manufacturers and policymakers consider these community-informed insights to guide the development and deployment of more acceptable LLINs.