Its aim was to undertake laboratory and epidemiological research on the common cold, with a view to reducing its human and economic costs… Thirty volunteers were required every fortnight during trial periods. The unit advertised in newspapers and magazines for volunteers, who were paid a small amount. A stay at the unit was presented in these advertisements as an unusual holiday opportunity. The volunteers were infected with preparations of cold viruses and typically stayed for ten days. They were housed in small groups of two or three, with each group strictly isolated from the others during the course of the stay. Volunteers were allowed to go out for walks in the countryside south of Salisbury, but residential areas were out of bounds.
The unit was closed in 1989 after failing to find a cure. The British Library has archived a series of interviews with doctors and other CCU staff, part of their Archival Sound Recordings collections. Wonky sniffling details can be read in this PDF “The Common Cold–My Favourite Infection” written by a CCU researcher. A few recruiting articles from the archives of The London Times.
[note: the CCU is not to be confused with Porton Down, thanks to John Overholt for research help]