Seth Berkley wants to develop an AIDS vaccine. He wants a new way of harnessing science for the poor. He wants, for good measure, to help remake the international system. What's more, he's off to a good start.

Berkley runs something called the International AIDS Vaccine Initiative, which he set up in 1996. At the time, there was just about no interest in developing a vaccine to combat the HIV virus, even though vaccines have been at the center of every other human triumph over viral epidemics, from smallpox to polio to measles; and even though HIV infects nearly 6 million people every year.

That crazy lack of interest reflected the shortcomings of both government and markets. Public research centers shied away from the quest for a vaccine because they felt pressure from people who had already contracted the virus and who, understandably, wanted research on treatment, not vaccines. Besides, vaccine development seemed risky. It requires expensive clinical trials that are fraught with ethical dilemmas: One trial group gets vaccines, the other gets placebos, and you only get results when participants get HIV.

Meanwhile the private sector had its own reasons for failure. AIDS is a political disease, fraught with noise and name-calling: Companies usually avoid such territory. Worse, the biggest market for vaccines lies in poor countries, which cannot pay much for them. The drug firms feared that, if they spent years and millions developing a vaccine, political pressure would oblige them to supply the fruits of their efforts at affordable prices--meaning at a loss.

Confronted by this double failure of government and business, Berkley bet that a non-profit pressure group might have more success. He based his bet on a new device to marry public goals with private-sector ingenuity: A sort of cross between traditional philanthropy and venture capital. Having identified two groups of researchers, in North Carolina and in Britain, he invested $9.1 million in them; but instead of demanding a share of future profits in return for this capital, he demanded guarantees that a successful vaccine would be distributed cheaply in poor countries.

This "social-venture capitalism" has impressed illustrious benefactors. Last year Bill and Melinda Gates gave $25 million to Berkley's efforts, and that vote of confidence helped to bring in more millions, notably from the British government. What's more, the Gates team seems to regard Berkley's method as replicable: They have followed up with gifts to funds that seek vaccines for malaria and tuberculosis. It is too early to say for certain, but a new model for poor-country assistance seems to have been born.

Moreover, the Berkley story is part of a broader one, concerning the role of non-governmental organizations in international politics. Since the collapse of the Seattle trade summit last month, it has been tempting to regard non-governmental organizations (NGOs) as disruptive: Thanks at least partly to their protests, a chance to promote prosperity was missed. But, on subjects ranging from global warming to human rights monitoring, the impact of NGOs is hugely positive.

Berkley's vaccine initiative is another reminder of this positive potential. His tiny outfit is nimbler than governments and multilateral bodies; but it is not too tiny to goad those big bodies into action. Since Berkley started shouting about the scandal of the neglected vaccine, governments from New Delhi to Johannesburg to Washington have awakened to the need for research. The United Nations and the World Bank are turning up their interest. Last week Al Gore addressed the United Nations on the AIDS pandemic, and declared the administration committed to "maximum possible research."

The next challenge for Berkley will test his influence to the limit. His social-venture capital idea has stimulated efforts to supply a vaccine, but more work remains on the demand side. Even if a vaccine is offered to poor countries for no more than the cost of making it, some won't find the money. So Berkley wants to set up a purchasing fund with cash from rich governments, so that the vaccine can be bought and distributed the moment it has been shown to work.

How to make this happen? Berkley has an ally in the World Bank, whose boss, Jim Wolfensohn, is big on partnerships with NGOs. The bank, in turn, has allies in the rich governments that fund it; and all these people want to be on the same wavelength as hip philanthropists such as Gates. At the upcoming shmoozathon in Davos, Switzerland, Berkley will be winning converts; and he has hopes for a White House conference on vaccines scheduled for March. "It is not too late for Clinton to secure his legacy," Berkley suggests. "He could announce the creation of an international fund for AIDS vaccines, and he could do it flanked by Nelson Mandela and Bill Gates."

The writer is a member of the editorial page staff.