OBJECTIVETo study the levels of SARS-associated coronavirus IgG antibody of SARS patients, people who closely contacted SARS patients and normal subjects in Gansu province.

METHODSThe levels of SARS-associated coronavirus IgG antibody were measured by ELISA. The material included acute and (or) recovery period sera of 9 SARS patients, sera from 1,109 doctors and nurses closely contacted with SARS patients, laboratory workers, personnel for disease control and prevention, persons who contacted SARS patients, and sera from 978 normal subjects.

RESULTSSARS coronavirus IgG antibody was detected positive in 6 of the 9 patients, it was still positive in the sera twelve months after recovery; 1 of the closely contacted persons and 3 normal subjects were found positive.

CONCLUSIONThe positive rate of SARS coronavirus IgG antibody of patients was consistent with the clinical diagnosis. The low positive rate of the persons who closely contacted SARS patients and normal subjects suggests that SARS probably had no subclinical infection.