NIRI’s pioneering work on the physical durability of insecticide-treated mosquito nets (ITNs) has been referenced in a new World Health Organisation (WHO) technical consultation report, which examines how durability metrics could inform future vector-control decisions.
ITNs remain one of the most important tools for preventing malaria. However, their effectiveness depends not only on insecticidal performance, but also on whether the net remains physically intact and functional over time. In many settings, nets are expected to provide protection across a three-year distribution cycle, yet real-world durability can vary significantly depending on product construction, use conditions, user habits and local environmental factors.
NIRI researchers have collaborated on this breakthrough project with Bill and Melinda Gates Foundation, WHO and Innovative Vector Control Consortium (IVCC) to address the challenge of developing laboratory-based methods for assessing the resistance of mosquito-net structures to real-world modes of damage. This work has involved developing the resistance-to-damage score, or RD score, a single metric designed to reflect key physical performance attributes including bursting strength, snag strength and resistance to hole enlargement.
The new WHO technical consultation report discusses the evolution of this work into the weighted resistance-to-damage score, or wRD score, and considers how it could help link laboratory performance to operational life in the field. The report notes that wRD was positively associated with median net lifespan and that improved durability scoring could support more value-based procurement decisions.
This is a significant moment for applied textile science. By translating the mechanisms of field damage into measurable laboratory tests, NIRI’s work is now helping to create a stronger evidence base for how future ITNs are designed, assessed and selected.
Professor Stephen Russell, Technical Director of NIRI Group, said:
“Physical durability is a critical factor governing the effectiveness of ITNs. NIRI’s work focused on understanding how and why nets fail in use, then developing practical textile tests along with a new metric to inform new product development and procurement decisions. It is encouraging to see the importance of ITN durability measurement being discussed at global level.”
The WHO report also highlights the broader opportunity for durability metrics to support value-based procurement, where decisions consider not only the purchase price of a net, but also its likely period of effective protection. This approach could help to incentivise innovation, improve the allocation of resources and support malaria programmes in maintaining protection between distribution campaigns.
NIRI’s contribution to this field is set out in a series of peer-reviewed Journal papers:
- Development of a single resistance to damage metric for mosquito nets related to physical integrity in the field. Read more here.
- Physical durability: are bed nets getting any stronger? Read more here.
- The causes of holes and loss of physical integrity in long-lasting insecticidal nets. Read more here.
- Textile testing to assess the resistance to damage of long-lasting insecticidal nets for malaria control and prevention. Read more here.
- Correlation of textile ‘resistance to damage’ scores with actual physical survival of long-lasting insecticidal nets in the field. Read more here.
As the sector seeks to refine and validate durability-testing protocols, NIRI will continue to support the translation of textile science into practical tools that improve product performance, procurement decisions and public-health outcomes.
Matthew Tipper, NIRI’s CEO, says “to see NIRI’s pioneering work help improve mosquito net performance and contribute to saving lives is testament to collaborative innovation.”
The full technical consultation report is also available on the WHO website.
Contact NIRI to explore how our collaborative approach to R&D can support your development goals.
