Malaria is an important cause of death and illness in children and adults in tropical countries. Mortality, currently estimated at over a million people per year, has risen in recent years, probably due to increasing resistance to antimalarial medicines. Malaria control requires an integrated approach comprising prevention including vector control and treatment with effective antimalarials. The affordable and widely available antimalarial chloroquine that was in the past a mainstay of malaria control is now ineffective in most falciparum malaria endemic areas, and resistance to sulfadoxine-pyrimethamine is increasing rapidly. The discovery and development of the artemisinin derivatives in China, and their evaluation in South-East Asia and other regions, have provided a new class of highly effective antimalarials, and have already transformed the chemotherapy of malaria in South-East Asia. Artemisinin-based combination therapies (ACTs) are now generally considered as the best current treatment for uncomplicated falciparum malaria.
These treatment guidelines recommend antimalarials for which there is adequate evidence of efficacy and safety now, and which are unlikely to be affected by resistance in the near future. Much of the world's symptomatic malaria is treated in peripheral health centres or remote villages, where facilities are limited. The aim is therefore to provide simple and straightforward treatment recommendations based on sound evidence that can be applied effectively in most settings.
These guidelines are based on a review of current evidence and are developed in accordance with WHO's standard methodology. Clinical evidence has been assessed in an objective way using standard methods. The number of anti-malarial drug trials published has doubled in the past seven years, so these guidelines have a firmer evidence base than previous treatment recommendations. Inevitably, information gaps remain, however, and so the guidelines will remain under regular review and will be updated as new evidence becomes available. There are also difficulties when comparing results from different areas, as levels of drug resistance and background immunity vary. Where transmission levels and, consequently, immunity are high, the malaria symptoms are self-limiting in many patients, in particular in adults, so that drugs that are only partially effective may appear still to work well in many cases, misleading patients and doctors alike. But in the same location, the young child who lacks immunity to illness caused by P. falciparum may die if ineffective drugs are given.
The treatment recommendations given in these guidelines aim for effective treatment for the most vulnerable and therefore take all the relevant factors into account. These factors include laboratory measures, such as tests for in vitro antimalarial susceptibility and validated molecular markers of resistance, the pharmacokinetic and pharmacodynamic properties of the different antimalarials, and clinical trial results. Cost is a factor that has been taken into consideration in antimalarial treatment policy and practices. However, there are increasing international subsidies for antimalarials. Efficacy (both now and in the future) and safety have therefore taken precedence when making the recommendations. The malaria treatment guidelines given below are brief; for those who wish to study the evidence base in more detail, a series of annexes is provided.