6. History of or active immunodeficiency or immunosuppression caused by acquired or congenital diseases or caused by ongoing treatments such as chronic (greater than 14 days) high-dose corticosteroids (smaller than 5 mg prednisone [or equivalent] per day applied systemically, i.e. parenterally or orally), chronic or planned treatment with steroid eye drops or ointment at time of enrollment or radiation, or immunosuppressive drugs; low-dose corticosteroid topical products and nasal sprays used sporadically, i.e. pro re nata (according to circumstances) are permissible