• Sporadic corticosteroids: i. Age less than 9 years: ≥ 1 mg/kg/day of oral prednisolone or equivalent for 2 or more short courses of > 3 days in the 3 months preceding vaccination; ii. Age 9 years and above: ≥ 40 mg/day of oral prednisolone or equivalent for two or more short courses of > 3 days in the 3 months preceding vaccination; Note: Use of topical or inhalant corticosteroids prior to administration of the Study Vaccine or throughout the Study is acceptable