A new global malaria eradication strategy

On Oct 17, 2007, Bill and Melinda Gates called for complete eradication to be adopted as the new goal for the age-old fi ght against malaria, with the Director General of WHO, Margaret Chan, promptly echoing their conviction. Although debate over the wisdom of this target will continue, growing impatience with the low ambitions of current eff orts, fuelled by reductions in morbidity and mortality in some countries and progress in the development of new drugs and the fi rst-ever vaccine, will lead many decision makers to adopt eradication of malaria as the primary aim for their organisations. Two crucial questions stand out for those organisations that will now begin striving towards malaria eradication. When and how can it be achieved? Barring a magic bullet, which the most promising vaccine candidates are not, even the most optimistic malaria experts agree that eradication is decades away. The latter question, however, requires prompt attention. If a goal as ambitious as eradication is to be achieved, key groups—including donors, technical agencies, the scientifi c community, and countries where the disease is endemic—must align their energies and resources behind a common approach. That strategy should not be so prescriptive as to prevent appropriate variation among countries and donors, but should provide strong direction to ensure that global investment is well targeted and coordinated. Alternatively, if each donor and agency pursues their own agenda, the momentum gathered over the past 5 years will be lost and the fatalism and inaction that characterised the last decades of the 20th century will return. The malaria community should therefore take immediate steps, including broad debate and detailed technical consultation, to develop a common approach. In November, 2007, the Roll Back Malaria Partnership endorsed the creation of a global malaria business plan to guide collective eradication eff orts. With this Viewpoint, we hope to begin a debate on the strategy that can provide the best overarching framework for that plan and often collective malaria eff orts. The fi rst global strategy for the fi ght against malaria was adopted in 1955 at the start of the now notorious Global Malaria Eradication Program. This strategy called for massive and rapid application of di chlorodiphenyltrichloroethane (DDT) to interrupt transmission of the disease in countries around the world, regardless of geography and epidemiology (the notable exception was the exclusion of sub-Saharan Africa from this, so called, global strategy). This approach failed to interrupt transmission completely in many countries and malaria resurged to previous or even higher levels as eradication programmes crumbled and the strategy was abandoned. Although no-one will argue for the resurrection of this strategy in full, current impatience has revived interest in rapid indiscriminate attacks to eradicate malaria. Countries such as Kenya, Rwanda, and Zambia, which generated enthusiasm for an all-out attack with success in reducing malaria mortality by as much as 60%, also show why this strategy would not be advisable. Even if one of these countries did successfully eliminate transmission of malaria, they would fi nd it nearly impossible to sustain, because the parasite would inevitably be reintroduced by migrants and travellers from neighbouring countries with high transmission. Both experience and modelling show us that even a few infections can quickly lead to an epidemic in areas with effi cient vectors and limited protective measures. One of the principal lessons of the fi rst global eradication campaign was that the intensive eff ort needed to prevent resurgence in areas with continued exposure to parasite reservoirs cannot be maintained over time, because fi eld workers tire and lose precision and donors and governments shift resources to seemingly more urgent problems. Thus, even with the large arsenal and war chest available today, an indiscriminate push to eliminate malaria could lead to epidemics and erosion of years of work and investment. Today’s eff orts against malaria target a reduction in malaria mortality through progressive scaling up of a package of interventions. Progress in implementation was at fi rst poor. In the past 3 years, however, many countries have reported more promising results, with steep reductions in morbidity through increased use of insecticide-treated bed nets and other interventions. Seeking to expand this success, a new report launched at the 2008 World Economic Forum in Davos compellingly makes the case for a concerted short-term push to increase coverage of key interventions above 80% and slash morbidity and mortality in malaria-endemic countries. Aggressive scaling up should be the central component of any new strategy, with a dedicated group of well managed professionals helping countries to overcome bottlenecks and to achieve their goal. But the Davos report and other descriptions of this approach leave an essential question unanswered: what happens after aggressive short-term targets are achieved? Maintainence of intensive interventions will be diffi cult once malaria is no longer a major public-health threat and donors and populations lose interest. A breakthrough intervention, such as a highly protective and long-lasting vaccine, will not be available for at least 20 years, while widespread changes in living standards of the sort that contributed to elimination in Europe and the USA will undoubtedly take much longer. Hence, a short-term push must be complemented by a long-term strategy. Lancet 2008; 371: 1633–35