Severe acute respiratory syndrome (SARS) is a viral respiratory illness caused by a coronavirus. SARS was first reported in Asia in February 2003. The illness spread to more than two dozen countries in North America, South America, Europe, and Asia before the SARS global outbreak of 2003 was contained.

Transmission of the SARS virus is primarily from person to person, most readily by respiratory droplets produced when an infected person coughs or sneezes or through contact with an infected object or surface. Most cases of human-to-human transmission occurred in the healthcare setting, in the absence of adequate infection control precautions. Implementation of appropriate infection control practices, as well as heightened sanitation, brought the global outbreak of 2003 to an end.