Severe Respiratory Distress Syndrome suddenly emerged as an international threat in 2002-2003. Little is known about its natural history or managment. A protocol has been developed and approved to bring patients to the Clinical Center to study the natural history of this disease, with special emphasis on duration of viral shedding and host response to the virus. This patient is open to enrollment should the disease develop during the 2003-4 season. A protocol is also in development in collaboration with Chinese collaborators to pherese donors who have recovered from SARS in order to produce a high titer immunoglobulin that could then be used for a therapeutic trial in the United States or China. This is being done in collaboration and consultation with the Chinese health authorities and FDA.