LONDON — A British company reported Wednesday it had achieved the best results ever seen on an experimental human vaccine for bird flu and said mass production might be possible by 2007. A global health official called GlaxoSmithKline’s early results ‘an exciting piece of science.’ If future tests are as promising, it would be a major step in the frustrating campaign to protect people from a possible deadly flu pandemic. The U.S. government’s chief infectious disease scientist also was very optimistic. ‘The data are really very impressive,’ said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. ‘It changes the whole complexion of the issue that we have to face of getting enough vaccine for people who might need it in a pandemic.’ Glaxo’s results came from tests on 400 people in Belgium, most of whom developed strong immune responses from very low doses of the prototype vaccine. Success from wider tests of the vaccine could intensify competition with Sanofi-Aventis SA, whose vaccine unit, Sanofi Pasteur, reported disappointing results in March on its experimental product. It protected only about half of those who got two shots with a very high dose […]