一起SARS爆发的血清流行病学调查

目的 探讨SARS密切接触者的隐性感染和SARS患者血清中特异性抗体的消长情况。方法 采用中和试验法、间接酶联免疫吸附试验(ELISA)和免疫粘连法对北京一起SARS爆发案例中与重症SARS患者无防护密切接触的未发病者和续发SARS病例进行血清SARS特异性IgG抗体检测,采血时间为发病后或接触后24周左右。结果 共采集到32份血清,其中未发病密切接触者的血清19份,SARS康复期患者血清13份。三种方法检测结果:57份次未发病密切接触者的血清标本SARS-CoV抗体检测,结果均为阴性;39份次SARS康复期患者血清标本SARS-CoV抗体检测,38份次结果为阳性,1份次(用免疫粘连法检测)结果为阴性。病后24周左右的中和抗体效价为1:43(1:16～1:203)。结论 研究中未发现SARS密切接触者存在隐性感染;SARS患者病后24周左右血清IgG抗体仍维持在较高水平。

Serological investigation on close contacts to patients with severe acute respiratory syndrome in an SARS outbreak

Objective To study the evidence of severe acute respiratory syndrome(SARS) infection among close contacts to SARS patients and the level of sera IgG antibody in SARS cases. Methods Specific IgG antibody against SARS-CoV in serum samples from contacts to patients, five months before an SARS outbreak in Beijing. Neutralized test, ELISA and immunity adherence test were studied. Samples were collected after clinical onset of patients or close contacts to patients, for 22-24 weeks. 19 close contacts and 13 cases were included in the study. Results In close contacts, all tests were negative on three methods. All SARS cases were positive except one by immunity adherence test. The neutralized antibody levels were from 1 : 16 to 1 : 203, with medium level of 1:43. Conclusion According to our survey, there was no latent infection among close contacts. IgG antibody in sera continued to be at higher levels among SARS cases 22-24 weeks after onset.