Last week, international health leaders meeting at the annual World Health Assembly in Geneva made history by endorsing new guidelines to prevent health-worker brain drain from developing countries.

Nations unanimously adopted a voluntary global code that sets ethical principles around the movement of health workers. It was only the second time in the assembly's history that nations agreed to an ethical code.

The Global Code of Practice on the International Recruitment of Health Personnel acknowledges the right of health workers to migrate, while also acknowledging the right to the highest attainable standard of health. It calls on rich nations to meet their own internal demands without taking health workers away from countries that can least afford to lose them.

The critical shortage of health workers in developing countries is staggering. For example, Washington state has 11,000 doctors for its 6.6 million residents; Ethiopia by comparison has 2,000 doctors for its 80 million people. This would be equal to 165 doctors for the entire state of Washington.

Low-income countries invest significant resources to train health workers. Active recruitment of their doctors and nurses systematically deprives communities and entire populations of their right to health.

The loss of these investments equates to a form of reverse foreign aid. Not only is that ethically unacceptable, but speaking strictly parochially, it undermines the efforts of the many Seattle-based organizations working to improve global health. Discovering vaccines does no good if there is no one to administer them.

While the code is welcome news for those of us who work to advance health and human rights, we must admit the final version of the code was weakened in closed-door negotiations. After U.S. lobbying, rich nations reduced their responsibility for tracking the movement of health workers or for providing technical or financial assistance to developing countries.

Nonetheless, important elements of the document were retained and governments must now take steps to implement it.

Some countries have already moved to curb their active-recruitment practices. The United Kingdom and Norway have adopted policies to refrain from recruiting health workers from severe-shortage countries. Canada, too, has ramped up training programs so as to create less demand for foreign-trained health workers. The United States should follow suit.

As an initial step, we have to do a better job of tracking health-worker migration to inform policy decisions on increasing our domestic training programs to better meet demand. While we know approximately one in four U.S. physicians and about 220,000 nurses were trained abroad (largely in lower-income countries), those data are hard to come by.

Current information systems are fragmented and privatized. The only national data source on physicians is proprietary and only available for purchase from the American Medical Association. Nurse licensure data are available only on a state-by-state basis.

With 32 million uninsured Americans soon to be eligible for care, it's time to get serious about the fact that the U.S. health work force is too small and unevenly distributed across urban and rural areas. The Council on Graduate Medical Education has predicted the U.S. will be short approximately 85,000 physicians by 2020.

Thirty years ago, the U.S. was the only nation to oppose the World Health Organization's first ethical code, which limited the marketing of infant formula in poor countries because it undermined breast-feeding. This time, the U.S. stood with 192 nations in a show of global solidarity for the health of people in poor countries.

The Code of Practice offers real opportunity. We (and all nations) must now follow through as if we really meant it — because countless lives depend on it.