The epidemiology of severe acute respiratory syndrome in the 2003 Hong Kong epidemic: an analysis of all 1755 patients.
BACKGROUND
As yet, no one has written a comprehensive epidemiologic account of a severe acute respiratory syndrome (SARS) outbreak from an affected country.


OBJECTIVE
To provide a comprehensive epidemiologic account of a SARS outbreak from an affected territory.


METHODS
Epidemiologic analysis.


METHODS
The 2003 Hong Kong SARS outbreak.


METHODS
All 1755 cases and 302 deaths.


METHODS
Sociodemographic characteristics; infection clusters by time, occupation, setting, and workplace; and geospatial relationships were determined. The mean and variance in the time from infection to onset (incubation period) were estimated in a small group of patients with known exposure. The mean and variance in time from onset to admission, from admission to discharge, or from admission to death were calculated. Logistic regression was used to identify important predictors of case fatality.


RESULTS
49.3% of patients were infected in clinics, hospitals, or elderly or nursing homes, and the Amoy Gardens cluster accounted for 18.8% of cases. The ratio of women to men among infected individuals was 5:4. Health care workers accounted for 23.1% of all reported cases. The estimated mean incubation period was 4.6 days (95% CI, 3.8 to 5.8 days). Mean time from symptom onset to hospitalization varied between 2 and 8 days, decreasing over the course of the epidemic. Mean time from onset to death was 23.7 days (CI, 22.0 to 25.3 days), and mean time from onset to discharge was 26.5 days (CI, 25.8 to 27.2 days). Increasing age, male sex, atypical presenting symptoms, presence of comorbid conditions, and high lactate dehydrogenase level on admission were associated with a greater risk for death.


CONCLUSIONS
Estimates of the incubation period relied on statistical assumptions because few patients had known exposure times. Temporal changes in case management as the epidemic progressed, unavailable treatment information, and several potentially important factors that could not be thoroughly analyzed because of the limited sample size complicate interpretation of factors related to case fatality.


CONCLUSIONS
This analysis of the complete data on the 2003 SARS epidemic in Hong Kong has revealed key epidemiologic features of the epidemic as it evolved.
Leung
Gabriel M
GM
University of Hong Kong, Government of the Hong Kong Special Administrative Region, and Hong Kong Hospital Authority, Hong Kong, China.
Hedley
Anthony J
AJ
Ho
Lai-Ming
LM
Chau
Patsy
P
Wong
Irene O L
IO
Thach
Thuan Q
TQ
Ghani
Azra C
AC
Donnelly
Christl A
CA
Fraser
Christophe
C
Riley
Steven
S
Ferguson
Neil M
NM
Anderson
Roy M
RM
Tsang
Thomas
T
Leung
Pak-Yin
PY
Wong
Vivian
V
Chan
Jane C K
JC
Tsui
Eva
E
Lo
Su-Vui
SV
Lam
Tai-Hing
TH
D000328:Adult; D017677:Age Distribution; D000368:Aged; D016000:Cluster Analysis; D003710:Demography; D004196:Disease Outbreaks; D005260:Female; D006282:Health Personnel; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D017758:Infectious Disease Transmission, Patient-to-Professional; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D045169:Severe Acute Respiratory Syndrome / Q000453:epidemiology* / Q000635:transmission; D017678:Sex Distribution; D013997:Time Factors