Mass drug administration has been proposed as a way to reduce the transmission of Plasmodium falciparum malaria. A new study published in The Lancet indicates that such a program can be effective for reducing the disease for a limited time, especially if introduced when malaria transmission is low, but is not likely to eliminate the disease on its own.
Programs to control and eliminate P falciparum malaria have made great strides over the past 15 years. Nevertheless, many countries still experience endemic transmission. In 2015, the World Health Organization (WHO) Malaria Policy Advisory Committee recommended for the first time using mass drug administration (MDA) — the administration of medication regardless of infection status — in specific circumstances. But what role MDA should play in control and elimination strategies, and if it is to be used, where, how and when, has yet to be determined.
To help with such decisions, the Malaria Modelling Consortium, including researchers from the Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Topical Medicine in the United Kingdom, compared the effectiveness of 4 different mathematical models of MDA in different settings.
For the analysis, the researchers defined a standard intervention scenario (2 rounds of dihydroartemisinin-piperaquine at 70% coverage per year, 5 weeks apart, for 2 years) and a standard setting. They then compared different combinations — varying such factors as the number of rounds per year, the effective coverage of the drug, the interval between rounds, and the duration of the intervention, as well as seasonal timing and vector control — to produce 48 different MDA programs.
The results showed that all 4 models of MDA had the potential to reduce transmission of malaria. The findings also indicated that continuing an MDA program for 2 years is likely to be more effective than just 1 year, and predicted that an MDA program would be most effective in areas of low transmission of the disease. However, the results also found that MDA is not likely to be able to eliminate malaria. Without additional interventions, such as stepped up vector control, the disease is predicted to return to its pre-intervention level.
Brady, OJ, Slater HC, Pemberton-Ross P, et al. Role of mass drug administration in elimination of Plasmodium falciparum malaria: a consensus modelling study [published online May 26, 2017]. The Lancet. doi:10.1016/S2215-109X917)30220-6