SARS was first recognized at the end of February 2003 in Hanoi, Viet Nam.

case, a middle-aged man business man who has traveled extensively in South-East Asia before becoming unwell, was admitted to hospital in Hanoi on 26 February 2003

with a high fever, dry cough, myalgia and mild sore throat. Over the following 4 days he developed symptoms of adult respiratory distress syndrome, requiring ventilator support, and severe thrombocytopenia. Despite intensive therapy he died on 13 March after being transferred to an isolation facility in Hong Kong SAR.

On the basis of data from the SARS foci in Hanoi and Hong Kong SAR, the incubation period has been estimated to be 2.7 days, but usually 3.5 days. Attack rates of >56% among health care workers caring for patients with SARS is consistent in both the Hong Kong and Hanoi foci.