SCI Foundation is now Unlimit Health. Learn more about what the change means for our ongoing efforts to eliminate neglected tropical diseases

Mass drug administration

What is mass drug administration? 

Mass drug administration (MDA) is a campaign strategy in which all people in an area are given treatment regardless of their disease status. Delivering preventive chemotherapy (PC) through MDA is a central approach for disease control and prevention including against parasitic infections such as, schistosomes and soil-transmitted helminths. Preventive chemotherapy is recommended by the World Health Organization (WHO) and involves periodically treating at-risk populations depending on the level of infection in the community. For diseases schistosomiasis (SCH) and soil-transmitted helminthiasis (STH), this is typically once or twice a year, to ensure everyone infected is reached and to support the goal of elimination as a public health problem in affected countries.  

All programmes aimed at controlling or eliminating parasitic worm infections are owned and implemented by country governments. Each country’s programme is tailored to meet its populations’ needs. At Unlimit Health, we act as independent advisors sharing technical expertise, such as research and analysis, to support the scale-up and optimisation of programmes.  

Who is mass drug administration aimed at? 

MDA is aimed at everyone eligible who resides in an area that is endemic for disease. This includes school-age children (aged 5-14), but also adults, particularly high-risk groups such as women of child-bearing age (WCBA) and children under five years old.  

Where does mass drug administration take place? 

MDA often takes place in schools and treatment is given by teachers or volunteers, called community drug distributors (CDDs), who are trained by the programme. Usually, CDDs are selected by the community, and they tend to live and work in the areas where they deliver treatment.  

PC drugs, including praziquantel for SCH, and albendazole and mebendazole for STH, are generously donated by pharmaceutical companies each year.  

Can preventive chemotherapy eliminate parasitic worm infections? 

Consistent MDA for at-risk groups has historically been the strategy for controlling morbidity at the population level, with the aim of reducing disease transmission. It is considered to be one of the “best buys in public health” and has had great impact on disease burdens in affected communities.  

However, it is widely acknowledged that that MDA in isolation cannot lead to elimination of parasitic infections and to enhance the benefits that  it offers, other interventions must be considered alongside. The most recent WHO guidance recommends that water, sanitation and hygiene (WASH), environmental (including One Health) and behavioural interventions are essential measures to reduce transmission of infection.  

Does Unlimit Health support MDA? 

The recent WHO neglected tropical disease road map for 2030, to which our 2023-2028 strategy is aligned, represents a strategic shift from disease control strategies that focus on continuous rounds of PC to interventions that work both alongside and across sectors to target parasite transmission.  

Supporting the delivery of treatment through MDA remains a key part of our work to end parasitic disease. In 2022-2023, we supported the delivery of 50 million treatments for SCH and STH, reaching 39 million people. We also support our partners to expand their treatment programmes, enhancing access for people who currently do not receive treatment. For example, we are working as part of the Pediatric Praziquantel Consortium to develop an appropriate drug formulation to treat children under five years of age. 








Tibeltalech Kifle. Image by: Unlimit Health/END Fund/Indrias Getachew

“We are able to treat children who suffer from parasitic worms, which can make them malnourished and vulnerable to various diseases. This helps to protect children and keeps them healthy so they can pursue their education.”

Tibeltalech Kifle, a health worker in Ethiopia