- Use of any immunosuppressive therapy (Note: topical and inhaled/nebulized steroids are permitted). Participants on intramuscular, oral, or intravenous corticosteroid treatment should be excluded if they are receiving or expected to receive in the period from 30 days prior to Visit 1 through Visit 6 (30 days post-dose 4) more than 2 mg/kg per day of prednisone (or its equivalent), or more than 20 mg/d if they weigh more than 10 kg and are not otherwise immunocompromised. Excluded immunosuppressive therapies also include chemotherapeutic agents used to treat cancer or other conditions, and treatments associated with organ or bone marrow transplantation, or autoimmune disease.