The treatment of parasitic worms --specifically soil-transmitted helminths (STH)-- has been a focus of public health programs in developing countries in the last decade. There is a growing evidence base demonstrating the important health and educational benefits of deworming for children, and an increasing number of national school-based deworming programs around the world, some directly supported by Evidence Action (such as in Kenya, India, and Ethiopia).
School-Based Mass Deworming Works to Reduce Prevalence
Regular mass deworming of children once or twice a year has greatly contributed to the reduction in the prevalence of worms in several countries. For instance, in Kenya STH infection rates among children aged 5-14 dropped from 33% (pre-MDA) to 6.3% (post-MDA) after three rounds of school-based deworming. (Source: Kenya’s National School-Based Deworming Programme, Year 3 Results).
National, school-based deworming programs are the most efficient and cost-effective way to reach kids, and are a cornerstone of addressing the public health threat of STH and schistosomiasis in a growing number of countries.
But: Treating Children Alone Is Not Enough to Break Transmission
But there is a growing recognition that treatment of children alone might not be sufficient to break the transmission of worm infections. Infected adults constitute a latent reservoir of worm eggs and present a significant re-infection risk to children, in particular for hookworm, one of the three STH.
Currently, school-based deworming campaigns are conducted repeatedly for a number of years to reduce worm infection, but at this juncture there is not sufficient evidence to point to an “end game” for STH treatment.
If breaking transmission by treating adults is scientifically possible and practically feasible, it might be a cost-effective investment to make - in addition to school-based deworming. Indeed, preeminent epidemiologists have developed models that point to the possibility of breaking STH transmission.
Breaking Transmission: What Is The Most Cost-Effective Way?
A team of researchers at the London School of Hygiene & Tropical Medicine, the Imperial College London, and the Kenya Medical Research Institute, with implementation support from Evidence Action is looking into the possibility of breaking STH transmission by combining school-based deworming with a community-based intervention that specifically targets adults.
Unlike children who are quite easily reached in schools on deworming day, adults are much harder to reach for mass treatment. Other mass drug administration (MDA) campaigns are typically implemented through networks of community health workers that visit households door to door to administer treatment. But this approach can be expensive and time-consuming. Studies have also highlighted a number of other challenges with door-to-door campaigns: people might be omitted by drug distributors, away from home at the time of the visit, or not presented with proper information to understand the reasons for taking the drug, resulting in low levels of compliance.
So we are faced with a dilemma: Is it possible to expand the current school-based deworming programs to include entire communities -- potentially hundreds of millions of additional drug recipients -- and potentially break transmission of parasitic worm infections while keeping these campaigns financially and operationally feasible?
Enter Take Up
Evidence Action recently launched a related but separate research project, Take Up, to understand whether it’s operationally feasible to cost-effectively reach high coverage of adults with deworming medication. Take Up is looking into key questions impacting both supply and demand for treatment:.
On the supply side -- getting drugs to communities -- our research questions are mostly operational. What is the most efficient supply chain for the medication? What types of locations are best suited for treatment -- schools, health centers, market days? How many treatment posts should be set up per community? How long should treatment be made available? How do we best motivate a network of local drug distributors? This was the focus of a series of pilots we ran across 10 communities of Kakamega County in Western Kenya in March 2016.
But the truly exciting part of the project lies on the demand side: Understanding and increasing demand for deworming treatment among adult populations. Here, Take Up builds on behavioral economics to understand how social incentives and innovative messaging can be leveraged to motivate people to get dewormed. This is a new contribution to complement other studies conducted in this space.
Deworming as a Collective Action
A first round of interviews and focus group discussions in Busia County last October found that one of the main barriers to increasing demand among adults is that deworming is often perceived as a public good with low private benefits -- people know that deworming is good for their community, but do not see any personal benefit in seeking treatment themselves.
This is a collective action challenge, similar to vaccination or recycling: All households would benefit from high participation in their community, but fail to coordinate amongst one another. People are typically altruistic towards their community, but need assurance that their individual efforts will pay off.
One approach to encourage collective action for deworming is to promote public disclosure of having taken the drug -- not dissimilar to the “I voted” or “I donated blood” stickers in the U.S. This signals public uptake and introduces a system of social approvals/disapprovals for one’s behavior, where reputational concerns often induce more public contributions. We tested different public signals for Take Up including bracelets and permanent ink (like what is used during elections in many developing countries), given to adults participating in the deworming drive.
We are now comparing different combinations of supply-side operations and demand-side incentive schemes using the gold standard in impact evaluation, a cluster randomized controlled trial, that will be fully rolled out in July this year.
This will help us identify which approach is the most cost-effective and successful in mobilizing adults to get dewormed, revealing important lessons for existing school-based deworming and other mass drug administration programs around the world.
Ultimately, we hope Take Up will contribute to a better understanding of how to end the public health risk of parasitic worms by reducing reinfection across communities. In doing so, we can ensure that the current investments of governments and donors in school-based deworming programs are fully leveraged for the greatest public health benefit.