The swine flu pandemic has grown "unstoppable" and all nations will need access to vaccines, a WHO official has said, as 12 new deaths were reported and a study raised fresh concerns.
Britain, Brazil, Colombia, Mexico, the Philippines and Thailand all reported deaths on Monday, while Saudi Arabia shut an international school after 20 students were diagnosed with the A(H1N1) virus.
As the death toll increased, the World Health Organisation official said a swine flu vaccine should be available as early as September and all countries would need to be able to protect themselves.
A group of vaccination experts concluded after a recent meeting that "the H1N1 pandemic is unstoppable and therefore all countries would need to have access to vaccines," said Marie-Paul Kieny, WHO director on vaccine research.
Health workers should be at the top of the list for vaccination since they will be in high demand as people continue to fall sick, she added.
Countries would be free to decide on their national priorities, but other groups should include pregnant women and anyone over six months old who has chronic health problems, the WHO official said.