Factors associated with nosocomial SARS-CoV transmission among healthcare workers in Hanoi, Vietnam, 2003.
BACKGROUND
In March of 2003, an outbreak of Severe Acute Respiratory Syndrome (SARS) occurred in Northern Vietnam. This outbreak began when a traveler arriving from Hong Kong sought medical care at a small hospital (Hospital A) in Hanoi, initiating a serious and substantial transmission event within the hospital, and subsequent limited spread within the community.


METHODS
We surveyed Hospital A personnel for exposure to the index patient and for symptoms of disease during the outbreak. Additionally, serum specimens were collected and assayed for antibody to SARS-associated coronavirus (SARS-CoV) antibody and job-specific attack rates were calculated. A nested case-control analysis was performed to assess risk factors for acquiring SARS-CoV infection.


RESULTS
One hundred and fifty-three of 193 (79.3%) clinical and non-clinical staff consented to participate. Excluding job categories with < 3 workers, the highest SARS attack rates occurred among nurses who worked in the outpatient and inpatient general wards (57.1, 47.4%, respectively). Nurses assigned to the operating room/intensive care unit, experienced the lowest attack rates (7.1%) among all clinical staff. Serologic evidence of SARS-CoV infection was detected in 4 individuals, including 2 non-clinical workers, who had not previously been identified as SARS cases; none reported having had fever or cough. Entering the index patient's room and having seen (viewed) the patient were the behaviors associated with highest risk for infection by univariate analysis (odds ratios 20.0, 14.0; 95% confidence intervals 4.1-97.1, 3.6-55.3, respectively).


CONCLUSIONS
This study highlights job categories and activities associated with increased risk for SARS-CoV infection and demonstrates that a broad diversity of hospital workers may be vulnerable during an outbreak. These findings may help guide recommendations for the protection of vulnerable occupational groups and may have implications for other respiratory infections such as influenza.
Reynolds
Mary G
MG
National Centers for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA. nzr6@cdc.gov
Anh
Bach Huy
BH
Thu
Vu Hoang
VH
Montgomery
Joel M
JM
Bausch
Daniel G
DG
Shah
J Jina
JJ
Maloney
Susan
S
Leitmeyer
Katrin C
KC
Huy
Vu Quang
VQ
Horby
Peter
P
Plant
Aileen Y
AY
Uyeki
Timothy M
TM
D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D016022:Case-Control Studies; D015331:Cohort Studies; D004196:Disease Outbreaks; D006723:Hong Kong / Q000208:ethnology; D006757:Hospital Units; D006801:Humans; D017758:Infectious Disease Transmission, Patient-to-Professional / Q000032:analysis*; D008875:Middle Aged; D009741:Nursing Staff, Hospital; D016273:Occupational Exposure / Q000032:analysis / Q000706:statistics & numerical data*; D010564:Personnel, Hospital; D018570:Risk Assessment; D012307:Risk Factors; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology; D016036:Seroepidemiologic Studies; D045169:Severe Acute Respiratory Syndrome / Q000453:epidemiology* / Q000635:transmission; D014195:Travel; D014744:Vietnam / Q000453:epidemiology
D000914:Antibodies, Viral