Severe acute respiratory syndrome: an update.

Purpose Of Review: An international outbreak of severe acute respiratory syndrome, a recently recognized syndrome caused by the newly identified severe acute respiratory syndrome-associated coronavirus, began in November 2002 and ended in July 2003. Since then, a large body of research on the syndrome has been published; the most updated developments are summarized here.

Recent Findings: Recent findings suggest that animal severe acute respiratory syndrome-like coronaviruses may have been transmitted to humans without detection for years before the recent outbreak, and that such transmission may be continuing today. The 2002-2003 outbreak probably originated from similar animal-to-human transmission, but selection and purification of the animal severe acute respiratory syndrome-like virus appears to have occurred, creating the more virulent severe acute respiratory syndrome-associated coronavirus. Recent studies have documented that severe acute respiratory syndrome-associated coronavirus is primarily transmitted via contact and/or respiratory droplets and that the combination of standard, contact, and droplet precautions is generally effective for its control. It has been shown that severe acute respiratory syndrome-associated coronavirus is typically relatively inefficiently transmitted, with the notable exception of transmission during superspreading events. Insights into the pathogenesis of severe acute respiratory syndrome have been made: one study suggests that human leukocyte antigen HLA-B*4601 is a possible risk factor for more severe disease, while another identifies angiotensin-converting enzyme 2 as a cellular receptor for severe acute respiratory syndrome-associated coronavirus. Promising treatments have been identified, including interferons, an anti-spike monoclonal antibody, and fusion inhibitors. In addition, many promising vaccines are currently in development.

Summary: New findings regarding severe acute respiratory syndrome are continuing to be discovered at an unprecedented pace, permitting a better understanding of the disease and enabling better preparation for its possible return.