The severe acute respiratory syndrome epidemic in mainland China dissected

Abstract

This paper provides a review of a recently published series of studies that give a detailed and comprehensive documentation of the severe acute respiratory syndrome (SARS) epidemic in mainland China, which severely struck the country in the spring of 2003. The epidemic spanned a large geographical extent but clustered in two areas: first in Guangdong Province, and about 3 months later in Beijing with its surrounding areas. Reanalysis of all available epidemiological data resulted in a total of 5327 probable cases of SARS, of whom 343 died. The resulting case fatality ratio (CFR) of 6.4% was less than half of that in other SARS-affected countries or areas, and this difference could only partly be explained by younger age of patients and higher number of community acquired infections. Analysis of the impact of interventions demonstrated that strong political commitment and a centrally coordinated response was the most important factor to control SARS in mainland China, whereas the most stringent control measures were all initiated when the epidemic was already dying down. The long-term economic consequence of the epidemic was limited, much consumption was merely postponed, but for Beijing irrecoverable losses to the tourist sector were considerable. An important finding from a cohort study was that many former SARS patients currently suffer from avascular osteonecrosis, as a consequence of the treatment with corticosteroids during their infection. The SARS epidemic provided valuable information and lessons relevant in controlling outbreaks of newly emerging infectious diseases, and has led to fundamental reforms of the Chinese health system. In particular, a comprehensive nationwide internet-based disease reporting system was established.

Keywords: China; avascular necrosis; case fatality ratio; epidemic preparedness.; severe acute respiratory syndrome.

Figure 1

The temporal distribution of SARS outbreaks in the six most seriously affected geographic areas of mainland China by plotting the number of new cases per day of onset since the first SARS case on November 16, 2002, in Guangdong Province.

Figure 2

Comparison of the case fatality ratios for SARS patients in Beijing, Guangdong and Tianjin with age. Intervals indicate 90% binomially distributed confidence intervals. The values between parentheses represent the overall case fatality ratio for each of the three areas.

Figure 3

Estimated effective reproduction number (R_t) (number of secondary infections generated per primary case) during the SARS epidemic in China. Values represent average R_t (central white line) and associated 95% (grey) and 80% (black) confidence intervals, by date of symptom onset. The critical value of R_t=1, below which sustained transmission is impossible, is marked with a broken horizontal line. Arrows reflect the moment of important events and public health control measures: (1) Local newspaper report about outbreak of unknown infectious disease in Guangdong (2 January); (2) Start of control in Guangdong hospitals: e.g. isolation, contact tracing (1–3 February); (3) First official report of outbreak by Guangdong authorities (11 February); (4) WHO global alerts; first mentioning of SARS (12–15 March); (5) First protocol of SARS control; start isolation in Beijing hospitals (2 April); (6) Full control under central guidance by the Chinese authorities, including mandatory reporting of SARS; definition of diagnostic criteria and treatment (11–14 April); (7) Stringent control measures: quarantine in airports and stations; closure of schools, universities and public places; daily reporting by the national media (19–26 April); (8) Public holiday cancelled; new 1000-bed SARS hospital opened (1 May); (9) Further improvement of various guidelines and protocols (4–9 May).