Fig. 1. Epidemic curve of Tan Tock Seng Hospital (TTSH) staff (n = 59) who were infected by severe acute respiratory syndrome (SARS) coronavirus. Admission of index case occurred on March 1, 2003. Use of standard personal protective equipment (PPE) was implemented on March 20, 2003, in the operating room (OR) complex. Hospital-wide use of standard PPE was implemented on March 23, 2003. Last infected healthcare worker in TTSH presented on April 5, 2003.