NEW YORK – The critics of foreign aid are wrong. A growing flood of data shows that death rates in many poor countries are falling sharply, and that aid-supported programs for health-care delivery have played a key role. Aid works; it saves lives.One of the newest studies, by Gabriel Demombynes and Sofia Trommlerova, shows that Kenya’s infant mortality (deaths under the age of one year) has plummeted in recent years, and attributes a significant part of the gain to the massive uptake of anti-malaria bed nets. These findings are consistent with an important study of malaria death rates by Chris Murray and others, which similarly found a significant and rapid decline in malaria-caused deaths after 2004 in sub-Saharan Africa resulting from aid-supported malaria-control measures.Let’s turn back the clock a dozen years. In 2000, Africa was struggling with three major epidemics. AIDS was killing more than two million people each year, and spreading rapidly. Malaria was surging, owing to the parasite’s growing resistance to the standard medicine at the time. Tuberculosis was also soaring, partly as a result of the AIDS epidemic and partly because of the emergence of drug-resistant TB. In addition, hundreds of thousands of women were dying in childbirth each year, because they had no access to safe deliveries in a clinic or hospital, or to emergency help when needed.These interconnected crises prompted action. The United Nations’ member states adopted the Millennium Development Goals in September 2000. Three of the eight MDGs – reductions in children’s deaths, maternal deaths, and epidemic diseases – focus directly on health.Likewise, the World Health Organization issued a major call to scale up development assistance for health. And African leaders, led by Nigeria’s president at the time, Olusegun Obasanjo, took on the challenge of battling the continent’s epidemics. Nigeria hosted two landmark summits, on malaria in 2000 and on AIDS in 2001, which were a crucial spur to action.At the second of these summits, then-UN Secretary-General Kofi Annan called for the creation of the Global Fund to Fight AIDS, TB, and Malaria. The Global Fund began operations in 2002, financing prevention, treatment, and care programs for the three diseases. High-income countries also finally agreed to reduce the debt owed by heavily indebted poor countries, allowing them to spend more on health care and less on crippling payments to creditors.The United States also took action, adopting two major programs, one to fight AIDS and the other to fight malaria. In 2005, the UN Millennium Project recommended specific ways to scale up primary health care in the poorest countries, with the high-income countries helping to cover the costs that the poorest could not pay by themselves. The UN General Assembly backed many of the project’s recommendations, which were then implemented in numerous low-income countries.Donor aid did start to rise sharply as a result of all of these efforts. In 1995, total aid for health care was around $7.9 billion. This inadequate level then crept up slowly, to $10.5 billion by 2000. By 2005, however, annual aid for health had jumped another $5.9 billion, and by 2010, the total had grown by another $10.5 billion, to reach $26.9 billion for the year.The expanded funding allowed major campaigns against AIDS, TB, and malaria; a major scaling up of safe childbirth; and increased vaccine coverage, including the near-eradication of polio. Many innovative public-health techniques were developed and adopted. With one billion people living in high-income countries, total aid in 2010 amounted to around $27 per person in the donor countries – a modest sum for them, but a life-saving one for the world’s poorest people.The public-health successes can now be seen on many fronts. Around 12 million children under five years old died in 1990. By 2010, this number had declined to around 7.6 million – still far too high, but definitely an historic improvement. Malaria deaths in children in Africa were cut from a peak of around one million in 2004 to around 700,000 by 2010, and, worldwide, deaths of pregnant women declined by almost half between 1990 and 2010, from an estimated 543,000 to 287,000.Another $10-15 billion in annual aid (that is, roughly $10-15 more per person in the high-income world), bringing total aid to around $40 billion per year, would enable still greater progress to be made in the coming years. The MDGs for health could be achieved even in many of the world’s poorest countries.Unfortunately, at every step during the past decade – and still today – a chorus of aid skeptics has argued against the needed help. They have repeatedly claimed that aid does not work; that the funds will simply be wasted; that anti-malaria bed nets cannot be given to the poor, since the poor won’t use them; that the poor will not take anti-AIDS medicines properly; and so on and so forth. Their attacks have been relentless (I’ve faced my share).The opponents of aid are not merely wrong. Their vocal antagonism still threatens the funding that is needed to get the job done, to cut child and maternal deaths by enough to meet the MDGs by 2015 in the poorest countries, and to continue after that to ensure that all people everywhere finally have access to basic health services.A decade of significant progress in health outcomes has proved the skeptics wrong. Aid for health care works – and works magnificently – to save and improve lives. Let us continue to support these life-saving programs, which uphold the dignity and well-being of all people on the planet.Jeffrey D. Sachs is a professor at Columbia University, Director of its Earth Institute, and a special adviser to United Nations Secretary-General Ban Ki-Moon.