Five Western nations late last week announced they would fork over $1.5 billion to an effort designed to speed delivery of vaccines to developing countries. As Scientific American reported earlier this month, officials from Italy, the U.K., Canada, Norway and Russia met in Rome on February 9, where they announced that their governments would commit the funds for vaccines against pneumococcus, which causes pneumonia and meningitis that kill up to a million children every year.

The countries pledged the monies to create what amounts to an artificial market for the vaccines to provide incentive for pharmaceutical companies to introduce next-generation pneumococcal injections more rapidly, which could then be shipped to impoverished countries. This strategy, called an advance market commitment (AMC), requires donors to pay top dollar for a set number of doses. In return, participating vaccine makers agree to provide high-quality products that meet prearranged effectiveness requirements and to supply them at below cost once funds dry up.

Italy has pledged the most funds, $635 million, followed by the U.K. with $485 million, Canada ($200 million), Russia ($80 million) and Norway ($50 million). The Bill and Melinda Gates Foundation has also pledged $50 million to the effort.

Public officials consider vaccines a cost-effective way to improve global health. But scientific and economic obstacles have stymied the development of effective vaccines against many of the developing world's most deadly diseases, such as malaria and HIV as well as pneumococcus, the leading vaccine-preventable killer of children under the age of five. The success or failure of the pneumococcus AMC could determine whether similar programs should be created to hurry drugs for other diseases to needy populations.

Some experts caution that the AMC funds could end up going to vaccines that are inappropriate for the developing world, making it riskier to implement than traditional fixes. "If existing drugs, technologies and methods were properly distributed, the benefits for the world's poorest people would be immense," says economist Andrew Farlow of the University of Oxford. Farlow says another potential stumbling block to introducing new vaccines is the difficulty, particularly in sub-Saharan Africa, of administering vaccinations and drugs.

Supporters of the AMC concept say that it addresses an immediate problem by providing a reason for manufacturers to provide pneumococcal vaccines to needy populations. "If we don't have an AMC, we're going to have lifesaving pneumococcal vaccines developed for rich countries but there's not going to be enough capacity to supply them to the poor countries," says Orin Levine, executive director of PneumoADIP at Johns Hopkins Bloomberg School of Public Health. With the AMC, "we'll get more manufacturing capacity and we'll get changes in the formulation," such as multidose vials more suitable for transport than single-shot packages.

He says companies might also devote more research and money into preparing pneumococcal vaccines that protect more people in the developing world. Prevnar, a pneumococcal vaccine approved for sale last year by Wyeth, provides immunity to seven strains of the bacteria that are common in Western countries but represent half or less of the cases in parts of Africa. Levine says an injection that worked on nine to 13 pneumococcal strains would protect against 75 to 80 percent of cases worldwide. Both Wyeth and GlaxoSmithKline have such broader spectrum vaccines in the pipeline.

Global access to vaccines has been improving, now reaching close to 90 percent in some parts of the developing world, says Michel Zaffran, deputy secretary for the Global Alliance for Vaccines and Immunization (GAVI Alliance), an aid group that works to improve global vaccine coverage and helped develop the pilot AMC.

Zaffran says the World Health Organization will establish a committee to craft safety and effectiveness requirements that vaccines will have to meet to be eligible for the funds. According to Andrew Jones, a senior program officer for GAVI, the committee will likely set the bar for effectiveness relatively high. "It would be very unexpected to see them set it low enough that the current vaccine [Prevnar] would qualify," he says.

Once specifications are agreed on, the AMC advocates say it will be up to drugmakers to pick which strains to tackle and how to package the vaccine, and for the specific countries to decide which ones, if any, to purchase. "We are not skewing the market," Zaffran says. "We are not choosing the winner,"—or winners, if companies produce more than one eligible vaccine. "We are creating an incentive where it doesn't exist at the moment."

AMC proponents acknowledge that companies face considerable uncertainty about how quickly and how much vaccine poor countries would buy. Zaffran says that GAVI and other groups are working on ways to stimulate and better predict that demand. Note: parts of this article were modified after publication.