Jeffrey Sachs, director of the Earth Institute and one of the world's leading economists, has, along with other global experts, called for mass distribution of insecticidal bednets to fight malaria. The call is made in a Comment published early Online and in an upcoming edition of the Lancet.

Professor Sachs, along with director of the Earth Institute's Malaria Programme Awash Teklehaimanot ,and Professor Chris Curtis from the London School of Hygiene and Tropical Medicine say that long-lasting insecticidal bednets (LLINs) are a major way of controlling malaria, and that protection can be achieved for as little as $0.60 per person per year. The nets have two kinds of protective effects -- one for the people directly under them, and one for the community at large.

LLINs work in three ways: by killing some of the malaria-carrying Anopheles mosquitoes within a few minutes, repelling mosquitoes that are not killed, and acting as a mechanical barrier to biting. LLINs protect not only the user under the net, but decrease the risk of other people coming into contact with an infected mosquito. This results in the so-called "mass effect", similar to the "herd immunity" effect seen in communities which have had mass vaccination against various infectious diseases.

The authors say that combining maximum LLIN coverage with timely treatment for individuals who develop malaria will provide optimum community protection, and call for donor agencies to protect everyone in infected communities, not only people deemed "vulnerable." The authors say: "This rationale is a false economy. First, the donors miss the chance to reduce malaria transmission if they narrow the protection against the disease.

"Secondly, and crucially, the donors' definition of vulnerable is too narrow. The donors seek to protect children younger than five years and women who are pregnant, on the grounds that malaria is especially likely to kill individuals in these two groups. Yet children older than five years and adults other than pregnant women are also vulnerable to severe illness, death, and substantial economic costs from the disease."

Present coverage with LLINs in Africa remains low, with many places providing nets for 10% or less of the community. The authors applaud recent mass distribution campaigns by the International Red Cross, the Global Fund against AIDS, Tuberculosis and Malaria, and other partners. However, they criticise "social marketing" of LLINs, in which sales have been limited to the previously defined vulnerable groups or those who can afford to pay -- resulting in low LLIN coverage, particularly in rural areas. The authors say: "Free mass-distribution of LLINs' can work effectively, especially if the distribution is not only to vulnerable individuals but to all sleeping sites in every household."

Thanks to various donor agencies, there have been success stories of mass LLIN distribution, for example Ethiopia has experienced a huge increase in numbers of nets distributed since 2004, after years of inadequate coverage. The authors say: "Although the success stories in Ethiopia, Niger, Togo, Sao Tome , and Principe are exciting, the shocking truth is that major donor agencies have continued to promote social marketing, despite its clear inadequacy."

The Comment concludes with the authors calling for malaria-endemic countries and donor agencies to abandon social marketing in all malaria-affected areas, and to change to a policy that regards antimalarial commodities as public goods to be available free of charge for mass distribution.

The authors say: "Comprehensive malaria control in Africa is achievable by 2010, at the minimal cost of $3 billion per year if sound principles of public health and economics are observed. Millions of lives can be saved, and Africa will be given vital help in escaping from the vicious circle of poverty and disease that continues to grip the continent."

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Contact: Clare Oh
Lancet