Fears of a global flu pandemic have been realised, with the worldwide alert being raised to its highest possible level: six. The World Health Organisation said an H1N1 flu pandemic is now underway, the first for four decades, although the WHO said it was still a moderate pandemic.“The scientific criteria for an influenza pandemic have been met,” said the WHO chief Dr Margaret Chan. “I have therefore decided to raise the level of Influenza Pandemic alert from Phase 5 to Phase 6. The world is now at the start of the 2009 influenza pandemic.” Germany has confirmed 30 cases of the virus at a Japanese school in Dusseldorf. The school has been closed until at least next week, and the infected children have been placed in quarantine. On the other side of the world, Hong Kong confirmed its first cluster of cases, forcing all childcare centres and primary schools to close for at least two weeks. More than 27,000 cases have been confirmed around the world, with the deaths of 141 people. Unlike more common seasonal flu, the H1N1 virus has attacked mainly young adults and teenagers. The WHO has not recommended border closures and travel restrictions, and said a vaccine should be available within about two weeks.