A dangerous type of childhood meningitis has been virtually eliminated in Uganda in just five years after a vaccine was introduced, according to a study released this week. That should save the lives of 5,000 children a year, the authors estimated. "This is the first time we've seen this kind of impact, a 100 percent drop,' said Dr. Julian Lob-Levyt, executive secretary of the GAVI Alliance, which paid for the vaccines. "We hope this can be repeated in other countries.' The study, released by the World Health Organization, monitored cases from 2001 to 2006. The vaccine, known as Hib, protects against haemophilus influenzae type B, a bacterium that can inflame the lining of the brain or cause pneumonia. Each year, it kills 386,000 children globally. Three million more have severe side effects like deafness, paralysis or retardation. The vaccine has existed since 1991 but was rare in the third world until the creation of the alliance