| Severe Acute Respiratory Syndrome (SARS) is a newly emerging infectious disease among human beings. An imported case caused a SARS nosocomial outbreak in Tianjin on April 15th 2003. Using the hospital as epidemiological scene, we investigated the features of this SARS nosocomial outbreak and studied the changes of serum antibody level specific to SARS coronavirus (SARS-Cov) in acute and recovering phases of SARS patients;The evaluation of antibody against SARS-Cov is great important to clarify whether exist SARS-Cov latent infection.Objectives: Investigating the characters of a SARS nosocomial outbreak as well asthe effectiveness of the measurements for infection control though descriptive study;Observing the kinetics of antibody level among SARS patients, and comparing the IgG (specific for SARS-Cov) level between SARS and non-SARS patients by seroepidemiological study to elucidate the changes of IgG level and whether exist SARS latent infection.Methods: Using descriptive epidemiology to reveal the characters of SARS nosocomial infection. Using prospective epidemiology to study the seroepidemiological features in SARS epidemic region.Results:1. The descriptive study of SARS nosocomial outbreak showed:(1) An imported case caused SARS outbreak in a hospital. SARS spread in thehospital at the initial stage because of lack prevention conscious and infection control measures. (2) This SARS nosocomial infection produce three generations of patients with 110 cases which most of them were appeared at 4 and 8 day after SARS outbreak. More female patients are involved in this outbreak and most of the patients are youth. Nurses and doctors occupied at high ratio among hospital workers. As to the distribution of departments, most infection occurred at the department where the index patient was found. The department where the first patient appeared was considered as infectious centers, which spread the SARS-Cov to other neighboring departments. The elevator played an important role in the spread of SARS. (3) The adopted measures, including isolation of different regions, evaluation of population and strengthen the personal protection, effectively control the SARS nosocomial outbreak.2. The results of seroepidemiology of SARS outbreak showed: (1) IgG against SARS-Cov remained positive for a long time and has no sign to become negative. The average value of OD for IgG displayed various level at different phases. The antibody remained a low level at the 4th week after disease onset and reached at the highest level at the 22th week (the average value of OD is 1.0744). Thereafter, the IgG began to decline slowly but still maintained a high level (the average value of OD is 0.91807). The level of IgG (the average value of OD is 0.56471) at 66th week was slightly higher than that of 4th week. (2) The survey considering the high risk population in hospital, natural population in isolated region and healthy population in the region with no SARS epidemic showed that the positive rates of IgG against SARS-Cov were 0.61 (3/488), 0 (0/100), and 0 (0/100)respectively.Conclusion: The administration of different units, strict disinfection and strengthen of personal protection in hospital could control the cross infection of SARS effectively. The level of serum antibody IgG of the patients persisted a high level in a long period of time. There were no latent SARS-Cov infection in population.
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