Four times Indonesia has agreed to share samples of the bird flu virus with the World Health Organisation and four times Jakarta has reneged on the deal. The WHO's protracted battle with Indonesia over the H5N1 virus, the strain needed to develop a vaccine, underlines the difficulties of combating global health crises without international cooperation.

Indonesia is the country hardest hit by human avian influenza, suffering 81 of the 192 fatalities reported in the past four years. However it is locked in a conflict with the WHO as to who would benefit from the development of any vaccine against a deadly pandemic.

The Indonesian health ministry decided to withhold samples of the virus in December as it feared that any vaccine developed from its strains by pharmaceutical companies would be too costly for developing nations. The government said it wanted to retain control of the intellectual property rights connected with the virus's deadly strain and was angered on learning that an Australian drug manufacturer had developed a vaccine using the Indonesian H5N1 strain without permission.

Jakarta blamed the WHO for the development and feared it would lose out, but was persuaded it should share the strains for the sake of "global public health security". Yet the samples Jakarta sent to a WHO-affiliated laboratory in Japan last May were all unusable since they contained no live viruses.

The WHO recently singled out Indonesia as the only country in the world not sharing samples of the virus. China stopped sharing H5N1 specimens with the WHO for almost a year before sending samples in June, while Vietnam said it had sent samples but had encountered delivery problems.

This month Indonesia's deputy health minister for research, Triono Soendoro, said Jakarta would not share the samples until a global mechanism was in place giving developing countries access to the vaccines and helping them make their own medicines.

David Heymann, the WHO's assistant director-general for communicable diseases, is optimistic, saying a global system agreeable to Jakarta could be completed at an intergovernmental meeting in November. But he said he was concerned that by not sharing samples Jakarta was putting its own population at risk. If the strains were not passed to the pharmaceutical firms, subsequent vaccines would fail to cover elements of the Indonesian infections.