- Recent or current use of immunosuppressive medication, including systemic glucocorticoids (corticosteroid nasal sprays and topical steroids are permissible in all groups; inhaled steroid use is not permissible except for non-LAIV Group only). Use of oral steroids (<20 mg prednisone-equivalent/day) may be acceptable for volunteers 70-100 yrs of age after review by the investigator.