By Hannah Koenker, Technical Director, Tropical Health

AMP has supported mass ITN campaigns for almost two decades. In most cases, every three years national malaria programmes, in coordination with their partners, go through a huge effort to plan campaign registration and distribution activities, transport millions of ITNs by myriad means in often challenging conditions, and deliver these life-saving commodities to protect people from malaria. Following a mass distribution campaign, nets are put into use, but then begin to wear out, en masse, leading to the need for replacement campaigns another three years down the line. In many countries, national programmes are considering doing more frequent campaigns in response to shorter net lifespan than expected. But what if there were a way to reduce the effort, and maintain a steady level of ITN coverage over time?

Continuous distribution (CD), in addition to routine distribution through antenatal or immunization services at health facilities (which is assumed to be a channel used in malaria endemic countries to ensure ITN access for the most vulnerable populations), offers the opportunity to provide annual inputs of ITNs, typically through primary schools or via community health workers (CHWs) responding to demand from within communities. Tanzania has conducted annual school distributions in about half the country since 2013; Ghana delivers ITNs to schoolchildren between mass campaigns to offset some of the ITNs that wear out. Figuring out how many ITNs are needed for these types of channels, however, has always been a challenge. Complex modelling was needed, and meanwhile, mass campaigns were easy to quantify using the World Health Organization (WHO) guidance of dividing the population by 1.8.

New work by Hannah Koenker, funded through AMP’s Bill and Melinda Gates Foundation grant, attempts to find an easy quantification formula for CD. The analysis uses complex modelling, taking into account how long nets are expected to last in specific countries, and how different ITN delivery strategies contribute to ITN access over time. The “best” quantification approach is then recommended for each ITN delivery strategy, whether countries want to adopt a Tanzania-style approach where CD replaces mass campaigns, or a Ghana-style approach, where CD is carried out between campaigns.

Each national malaria programme generally sets its own targets at which ITN access should be maintained over time to ensure sustained malaria reductions. For countries with a net lifespan of two years or more wanting to maintain ITN access at 80 per cent, a full-scale continuous distribution strategy might require a “population times 20 per cent” quantification approach on an annual basis. Countries with a three-year net lifespan could use “population times 16 per cent” instead, since nets last a bit longer on average, and thus fewer of them are needed. A complete table of quantifiers for continuous distribution strategies for countries in Africa south of the Sahara is provided here.

The work also finds that full-scale continuous distribution strategies that maintain 80 per cent ITN access might require fewer nets overall, compared to current three-year mass campaign strategies – at least for countries with at least a two-year net lifespan. As for countries with shorter lifespans – less than two years – it will require more ITNs than are currently being procured, but CD strategies are likely to be more efficient at maintaining coverage compared to campaigns every two years and will require less level of effort from national programme staff.

The new quantification recommendations are already included in RBM CRSPC guidance, and some countries are using these to inform their planning for the years ahead. While costs of continuous distribution are estimated to be comparable to those of mass campaigns over time, AMP is working towards providing concrete budgeting templates for countries to ensure national programmes can compare their current distribution strategy via mass campaigns with CD options.