Remarks

• MDA may quickly reduce transmission of P. falciparum in very low to low transmission areas, but the effect wanes within 1–3 months. Therefore, if MDA is implemented, it should be one of several components of a robust malaria elimination programme (including, at minimum, good coverage of case-based surveillance with parasitological diagnosis, effective antimalarial treatment, and appropriate prevention tools and strategies) in order to reduce the risk of resurgence after the MDA programme has ended.
• MDA should be considered only for geographical areas where there is limited risk of importation of malaria either from adjacent communities or through travel of the population to endemic areas.
• Malaria programmes should consider whether sufficient resources are available to implement MDA without affecting other components of a robust malaria elimination programme.
• Very low to low transmission settings are defined as areas with P. falciparum parasite prevalence less than 10%, or P. falciparum incidence less than 250 cases per 1000 population per year [30]. These thresholds should not be regarded as absolutes for determining applicability of MDA implementation for transmission reduction. MDA implemented in areas with levels of transmission near these cut-offs may reduce both disease burden and transmission intensity.

Practical info The WHO guidance document, Mass drug administration for falciparum malaria: a practical field manual provides technical and operational guidance on the practical aspects of organizing a successful MDA program [161]. MDA has been found to have a short-term (1–3 months) impact on P. falciparum transmission in very low to low transmission areas. For MDA to contribute meaningfully towards achievement of malaria elimination, activities must already be in place to capitalize on the reduction in transmission achieved through the strategy. For that reason, if MDA is implemented, it should be as one component of a robust malaria elimination programme that includes, at minimum, good coverage of case-based surveillance, quality-assured parasitological diagnosis, effective antimalarial treatment and additional prevention strategies such as vector control. MDA will have maximal benefit to an elimination programme if the aim is to reduce transmission to the level that intensive surveillance and follow-up of every case can begin. MDA is likely to be most effective at reducing transmission in geographical areas where there is limited risk of importation of malaria either from adjacent communities or through travel of the population to endemic areas. Additionally, MDA rounds should be scheduled for time periods when populations exhibit low levels of movement in and out of the area in order to increase coverage of the intervention and reduce risk of importation. The impact of MDA will be greater, and last longer, if a large proportion of the population present in the area benefits from the treatment and prophylaxis provided by the medicine and if the rate of parasite importation is low. The frequency of rounds and duration of the MDA programme should take into account the local malaria epidemiology, the length of the prophylactic period provided by the antimalarial used, and the feasibility and cost of delivering each additional round. Consistent with trial data, mathematical models predicted that a single round of MDA would lead to an initial decrease in infections, but that the duration of effect would be short lived. Application of additional rounds is predicted to substantially improve the impact and duration of effect, but attempts should be made in later rounds to reach individuals who did not participate in earlier rounds. Achieving high coverage of the population and good adherence to the antimalarial medicine are critical aspects of MDA programmes. MDA programmes ask many asymptomatic, healthy people to take a medicine when they do not feel ill, with the potential for adverse reactions to occur. Improving coverage and adherence requires development of understanding and trust in the institutions implementing the programme. Community engagement is thus a key factor in determining the success of MDA in order to improve participation rates and adherence to the full treatment course of the medicine. A complete therapeutic course of antimalarial medicine, at doses recommended by the manufacturer, should be given to all eligible adults and children within the defined geographic area. Drug dosage should be determined by weight wherever possible, with dosing according to age only in situations where the person’s weight is unknown. The antimalarial medicines chosen for use in MDA should: a) be WHO recommended and prequalified; b) be efficacious against local parasites; c) be different from the medicine used as first-line treatment, where possible c) have a superior safety and tolerability profile; d) provide a longer duration of post-treatment prophylaxis with component medicines that have closely matched pharmacology to reduce the risk of new infections encountering only a single drug; e) have a positive public reputation and acceptability and f) be available and low-cost. Programmes may consider including a single, low-dose of primaquine in MDA programmes in order to increase the gametocytocidal effect, although the evidence was insufficient to discern an additional benefit of single lowdose primaquine. A drug regimen that can be administered as a directly-observed single dose is preferred to multi-day regimens. Depending on the medicine chosen, certain population groups may need to be excluded from MDA, such as: pregnant women in their first trimester; infants < 6 months of age or weighing < 5kgs; people recently treated with the same medicine; people with a known allergy to the medicine; anyone with severe acute illness or unable to take oral medication; people taking medication known to interact with the medicine used for MDA; and people with specific contraindications to the medicine used [161]. MDA should not be given to individuals receiving other forms of malaria chemoprevention (e.g. seasonal malaria chemoprevention, perennial malaria chemoprevention, or intermittent preventive treatment during pregnancy).