Chiron Corp. plans to launch this year a phase III trial of its Menjugate vaccine in the United States. The conjugate vaccine to protect against meningococcal C disease has already been approved for use in infants through adults in 24 nations. Chiron noted that Neisseria meningitidis causes approximately 120,000 cases of bacterial meningitis and sepsis annually, with about 3,000 of those cases in the United States.