In a study of 1192 patients with probable SARS reported in Hong Kong, 26.6% were hospital workers, 16.1% were members of the same household as SARS patients, 14.3% were Amoy garden residents, 4.9% were in-patients and 9.9% were contacts of SARS patients who were not family members. Using multivariate analysis of 1: 2 matched casecontrols of the remaining cases of undefined sources of infection, it was found that having visited mainland China, hospitals or the Amoy Gardens were significant risk factors. In addition, frequent mask use in public venues, frequent hand washing and disinfection of living quarters were significant protective factors. 21 A similar study conducted in Beijing on 94 unlinked probable SARS cases also showed that clinical SARS was associated with visits to fever clinics. 22 These indicate that household transmission is much less common and should allay public anxiety and panic.