The SARS epidemic in mainland China: bringing together all epidemiological data

Abstract

Objective: To document and verify the number of cases of severe acute respiratory syndrome (SARS) during the 2002-2003 epidemic in mainland China.

Method: All existing Chinese SARS data sources were integrated in one final database. This involved removing non-probable and duplicate cases, adding cases at the final stage of the outbreak, and collecting missing information.

Results: The resulting database contains a total of 5327 probable SARS cases, of whom 343 died, giving a case fatality ratio (CFR) of 6.4%. While the total number of cases happens to be equal to the original official reports, there are 5 cases overall which did not result in death. When compared with Hong Kong Special Administrative Region of China, China Taiwan, and Singapore, the SARS epidemic in mainland China resulted in a considerably lower CFR, involved relatively younger cases and included fewer health care workers.

Conclusions: To optimise future data collection during large-scale outbreaks of emerging or re-emerging infectious disease, China must further improve the infectious diseases reporting system, enhance collaboration between all levels of disease control, health departments, hospitals and institutes nationally and globally, and train specialized staff working at county centres of disease control.

Figure 1

System for reporting notifiable infectious diseases in mainland China at the time of the SARS epidemic, but before May 16, 2003.

Figure 2

(a) Epidemic curve of all 5327 cases of severe acute respiratory syndrome (SARS) in mainland China by date of onset from the first case on November 16, 2002, to the last on May 28, 2003, and by three locations. Other provinces including 449 cases from Shanxi, 282 from Inner Mongolia, 175 from Tianjin and 395 from other provinces, respectively. Date of onset was known for 5280 cases (99.1%) and the 47 missing values were obtained from imputation using date of admission to hospital, corrected for location and occupation (health care worker or not). Number of cases shows total number of new cases per day. For example, at the peak of the epidemic on April 23, 2003, the total number of new probable cases is 197, of which 129 cases are from Beijing, 14 cases are from Guangdong and 54 cases are from other provinces. (b) The distribution of probable SARS cases (n = 5327S) and population (n = 1292 million) by age group, in mainland China, in 2003.