: a user-friendly tool for predicting LLIN needs
In 2011 Albert Kilian, working for Malaria Consortium on NetWorks, created a user-friendly tool for predicting LLIN needs, building on a previously created NetCALC, simpler model written for Uganda. NetCALC’s purpose is to help malaria programmes in the management of a comprehensive ITN strategy by facilitating three
- Estimating achieved insecticide treated net coverage between household surveys based on the last survey result and number of nets distributed per year since then through various channels.
- Estimating the number of insecticide treated nets initially needed and as replacements to achieve and maintain set coverage targets.
- Projecting the capacity of various continuous distribution channels to sustain high coverage levels and thereby assist in decisions regarding the best overall insecticide treated net strategy.
In addition, NetCALC allows the variation of the expected ‘useful life’ of nets and through this feature facilitates estimations of expected savings through products with better durability. Prolonged ‘useful life’ of insecticide treated nets can be achieved through behavioural change communication in
terms of better care and repair.
Calculations in NetCALC use two major components. The first component is called the net crop, which is the number of nets available in a given system at a given time – i.e. the nets that are available for use by the population. The net crop is which is the sum of every net cohort of annual distributions carried forward and reduced by an annual loss rate as defined by the loss function. The second component translates this net crop into a coverage rate. By making some assumptions based on empirical data on how nets accumulate within the household as their availability increases as well as their distribution within the household, this component calculates the proportion of households with at least one insecticide treated net.
Recently updated, NetCALC now includes additional modules for distribution via curative health services, communities or the retail market.
In 2012, for version 2.0, the proportion of population with access to a insecticide treated net within the household was added as a new output variable, as recommended by Roll Back Malaria. All outputs were adjusted to comply with the WHO recommendation of ‘universal coverage’ being equal to one insecticide treated net per two people where the number of nets needed are equivalent to population.
As a tool for developing a comprehensive national system for net distribution, NetCALC is currently being used in Nigeria, Ghana and Uganda and will extend to other countries in 2013. In Ghana, staff were trained to use the tool as part of mass LLIN distribution activities for which Ghana received a commendation from the Alliance for Malaria Prevention.