Abstract: The aim was to investigate the family aggregation in the transmission process of severe acute respiratory syndrome(SARS) and to evaluate the infectiveness of SARS patients in different periods of disease epidemics, prognoses related factors and functions in restoration period. The index case is the clue of the investigation, transmission process, infectivity, transmission chain and contact history of SARS were studied through data analysis. Lung function and serum antibodies of recovered patient of SARS was studied. Eight people had a close contact with the index case, all of them were infected, and one of them died. It indicated that SARS case were infectious during their symptom period. Mortality of patients over sixty and/or complicated with other diseases was high. With lung function impediment in some degree, the IgG level was (1.11±0.48)g/L in SARS patients four weeks after recovery. In the investigation, people who had close contact with the index case in symptom period were infected. There is no evidence indicating that SARS case are no infections during their incubation period. The IgG level of recovered SARS patients is high.

Key words: severe acute respiratory syndrome, family aggregation, incubation period, symptom period, restoration period