Compositions, kits and methods are provided for Interferon analogs in order to promote general health or for therapeutic treatment of diseases. Human interferon analogs are made by fusion of interferon with human serum albumin. The bio-assay shows that the interferon analogs with the same cell protection against viral attack have 3-10 times longer acting function than interferon in vivo. These novel long acting interferon analogs can be used in treatment of patients with viral infection, such as SARS virus, HIV, HCV, HBV, or HAV, and the cancer diseases, such as leukemia and malignant melanoma. They also have a 3-5 times longer shelf-life compared with interferon.