Chinese drug company Sinovac won government approval Thursday for the country’s first home-grown swine flu vaccine, AFP reported. The company says the vaccine is effective after only one dose. Most experts had assumed that two doses per person would be required to provide adequate protection from A(H1N1) influenza. The World Health Organization congratulated Sinovac on its rapid work in developing the vaccine. Zhang Wei, head of the State Food and Drug Administration’s drug registration department, said that applications were being examined from nine other Chinese companies working on vaccines, with decisions expected by mid-September. With millions of students returning to school this week, China’s Health Ministry has warned of the growing risk of a mass outbreak of swine flu this winter. More than two dozen pharmaceutical companies around the world are rushing to ship new vaccines before the global pandemic enters an expected second wave.