The epidemiology of severe acute respiratory syndrome in the 2003 Hong Kong epidemic: an analysis of all 1755 patients
GM Leung, AJ Hedley, LM Ho, P Chau… - Annals of internal …, 2004 - acpjournals.org
Annals of internal medicine, 2004•acpjournals.org
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.
Design: Epidemiologic analysis. Setting: The 2003 Hong Kong SARS outbreak. Participants:
All 1755 cases and 302 deaths. Measurements: Sociodemographic characteristics; infection
clusters by time, occupation, setting, and workplace; and geospatial relationships were …
acute respiratory syndrome (SARS) outbreak from an affected country. Objective: To provide
a comprehensive epidemiologic account of a SARS outbreak from an affected territory.
Design: Epidemiologic analysis. Setting: The 2003 Hong Kong SARS outbreak. Participants:
All 1755 cases and 302 deaths. Measurements: Sociodemographic characteristics; infection
clusters by time, occupation, setting, and workplace; and geospatial relationships were …
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.
Design
Epidemiologic analysis.
Setting
The 2003 Hong Kong SARS outbreak.
Participants
All 1755 cases and 302 deaths.
Measurements
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.
Limitations
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.
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