Mass drug administration should be implemented as a tool to accelerate elimination: against

Abstract

In most malaria situations, mass drug administration (MDA) will result in a rapid reduction in the incidence and prevalence of malaria in the target population. However, due to practical reasons MDA hardly ever achieves coverage of the entire population and, therefore, will leave residual malaria infections in the population, from which malaria transmission can be resumed. Depending on the degree of access to prompt diagnosis and treatment and to effective vector control in the area, previous levels of incidence and prevalence will eventually be reached after MDA. It is, therefore, imperative that coverage with these interventions is ensured if MDA is to be implemented. Both effective vector control and access to treatment in combination will also reduce the malaria incidence and prevalence in an area, albeit more slowly than MDA. MDA's role in elimination has to be considered in relation to the following: (1) MDA is logistically difficult, ethically questionable and may evoke parasite resistance to the medicines being used, (2) MDA will only accelerate elimination by reducing the starting number of infections, but that (3) it will be of no benefit to elimination unless both effective vector control and good access to treatment are in place. All malaria elimination efforts have, and will, succeed with good access to treatment, effective vector control, and case surveillance and response systems, and most have not, and will not require MDA. The role of MDA in elimination, if any, will be limited to some very specific situations-small foci of high transmission within a larger area which has made progress towards elimination, to which the former constitutes a continuing source of parasites and, therefore, could jeopardize the elimination effort in the larger area. Elimination of malaria needs not only to be achieved but also be sustained. This is particularly challenging in tropical countries where the risk of re-introduction is high. The haste to eliminate malaria using MDA must be balanced by investment of time and effort to establish effective vector control programmes, and case surveillance and response systems based on diagnosis and treatment services, which are core requisites for achieving elimination, and the latter for sustaining it.

Keywords: Malaria; Malaria elimination; Mass drug administration.

Fig. 1

Probable growth in infection rates in Plasmodium vivax epidemics (incubation interval 20 days) from small origins (0.1% of the population), showing influence of basic reproduction rate (Reproduced from Macdonald [6])

Fig. 2

Probable growth in infection rates in Plasmodium falciparum epidemics (incubation interval 20 days) from small origins (0.1% of the population), showing influence of basic reproduction rate (Reproduced from Macdonald [6])