It's official — the eastern exodus is on. The number of people leaving countries in the former Soviet bloc for a new life in Western Europe has risen steeply since the European Union (EU) expanded east in April 2004. Some 60,000 Latvians have left the country since it joined the EU. More than 120,000 Lithuanians now live in Ireland alone. About 37,000 Slovaks have found jobs in Britain, along with half a million Poles. In fact, Poland has lost one in ten of its doctors abroad.

A certain amount of migration was part of the EU's plan when it set about enlargement. Policies encouraging mobility were drawn up in the hope that many of the migrants would return home flush with cash and new skills, and so bolster their home economies. But there is little evidence that this is happening. Instead, accumulating anecdotal evidence suggests that many of these movers are set to stay in their adopted homelands.

Although there are few data about scientists within this immigration pool, it seems fair to assume that this group — especially the most educated and skilled — make up a significant subset. After all, wages, infrastructure and grants are all better in the West. This sort of brain drain is especially damaging to the newer EU countries, because it will hamper their efforts to develop high-technology economies.

Philanthropic organizations such as the Howard Hughes Medical Institute and the Wellcome Trust have been leaders in keeping central and east European scientists rooted in their homelands — but they support only a handful of principal investigators in a few countries. For this strategy to be effective, countries themselves, perhaps bolstered by the EU and philanthropic organizations, need to adapt brain-gain strategies adopted in the West. Ireland is using its growing resources to repatriate its natives and Britain has aggressively sought to bring top scientists back from the United States. But until countries such as Latvia, Lithuania, Estonia and Poland have large enough economies — or formal EU repatriation schemes — enticing talent to come back home will be difficult.