Concern about the accessibility of data on flu strains remains an acute issue, which research administrators and political leaders should step forward and address.

Indonesia has become the hot spot of avian flu, with the virus spreading quickly in animal populations, and human cases occurring more often there than elsewhere. Yet from 51 reported human cases so far — 39 of them fatal — the genetic sequence of only one flu virus strain has been deposited in GenBank, the publicly accessible database for such information.

And last week in China, researchers belatedly published details of a case that tested positive for the virulent H5N1 strain in 2003 — contradicting the government's official line that none had occurred before November 2005. The unnecessary delay reaffirms the critical importance of better dissemination of flu data.

Back in Indonesia, the World Health Organization (WHO) has just confirmed that a cluster of eight cases in an extended family in northern Sumatra was the first unequivocal occurrence of limited human-to-human transmission of the virus. Whereas the WHO initially stated that the virus in the cluster showed “no significant” mutations, it now says that genetic changes in the virus account for the appearance of human-to-human transmission. In the Sumatra event, the transmission did not spread beyond the family.

Yet scientists outside the WHO networks have no access to these data. The problem last year spurred the US National Institutes of Health (NIH) to create a consortium to sequence and make public thousands of flu strains from humans and birds. Very quickly, this more open approach led to the useful discovery that viruses swap genes with each other more frequently than had been previously thought.

H5N1 sequences should be promptly deposited in a publicly accessible database.

Some political leaders are drawing the appropriate conclusions. Dennis Kucinich (Democrat, Ohio) and Wayne Gilchrest (Republican, Maryland) are circulating a letter in the House of Representatives that calls on Michael Levitt, the US health secretary, to require H5N1 sequences and other publicly funded research data “to be promptly deposited in a publicly accessible database, such as GenBank”.

An appropriate model for better data access is at hand. Earlier this month, the Paris-based World Organisation for Animal Health and the United Nations Food and Agriculture Organization said that they would work with the NIH to sequence H5N1 samples from birds and deposit them in GenBank. The WHO and its member states urgently need to establish a similar mechanism to ensure that data on human cases are immediately put in the public domain.