Global Expansion of Preventive Chemotherapy Delivered through Mass Drug Administration
Since its inception, the core of the U.S. Agency for International Development’s (USAID’s) Neglected Tropical Disease (NTD) Program has been a focus on expanding large-scale access to preventive chemotherapy by scaling up mass drug administration (MDA) for the NTDs targeted by the Program.
MDA is a strategy used to administer NTD medicines to the entire at-risk population of an area, most commonly a district. This strategy takes different forms in different countries, but usually consists of a campaign-style approach to deliver medications to all eligible people in at-risk communities, usually once or twice per year depending on the specific, targeted NTDs.
NTD control and elimination efforts have been deemed a “global health best buy” because they are relatively inexpensive and highly effective. MDA is a cost-effective approach that can reduce the occurrence, extent, and severity of the targeted diseases and can result in sustained reduction in disease transmission, so populations may no longer require treatment. For trachoma, MDA is a component of the comprehensive SAFE strategy.
To achieve expansion of MDA to populations in need, USAID’s country-level support has focused on addressing key programmatic questions and employing appropriate responses: Mapping, Monitoring Progress, and Evaluation.
Is MDA Required?
USAID Response: Mapping
- USAID supports NTD “mapping” to evaluate whether or not a given population requires MDA. Mapping is usually conducted at the district level, using survey methodologies endorsed by WHO. Mapping is intended to provide a relatively quick and inexpensive way of classifying a district as either “endemic” and requiring MDA, or “non endemic” and not requiring MDA.
- When USAID-supported mapping shows a district is in need of MDA, USAID works with the country to launch an MDA program. For most of the diseases targeted, this usually involves planning and implementation of 3—5 years of mass treatment.
Is MDA Working?
USAID Response: Monitoring
- Once a country begins to implement an MDA program, the program must be monitored for quality and impact. USAID supports countries to monitor program quality and effectiveness, for example by conducting surveys to ensure programs are achieving adequate drug coverage levels. The impact of MDA is usually monitored through sentinel site and spot-check surveys using standardized methodologies that provide information on the trend of infection over time.
Can MDA Be Stopped?
USAID Response: Evaluation
- Some of the NTDs targeted by USAID’s NTD Program are targeted for elimination as a public health problem by WHO. Evaluation is necessary to determine whether programs have reduced the prevalence of infection to levels in which transmission is likely no longer sustainable and the disease is no longer considered a public health problem. USAID supports countries to evaluate their programs, for example by conducting Transmission Assessment Surveys for lymphatic filariasis or impact and surveillance surveys for trachoma, to determine if and when MDA can be stopped.