question: PURPOSE OF REVIEW We have examined studies published since the severe acute respiratory syndrome outbreak that elucidate the mode of transmission of respiratory pathogens and the optimal means of interrupting their transmission, focusing on transmission in the intensive care unit. RECENT FINDINGS The severe acute respiratory syndrome may be transmitted by the droplet, contact and occasionally the airborne route. Transmission occurred most frequently when healthcare workers failed to use standard precautions such as hand washing or personal protective equipment designed to limit droplet and contact transmission. Aerosol-generating procedures increased transmission, but incomplete use of personal protective equipment during procedures was common. Recent publications have stressed the benefits of appropriate staffing levels, the use of single occupancy rooms, the immunization of healthcare workers against influenza, and the importance of healthcare workers remaining home when ill in reducing the morbidity and mortality of respiratory infection within the intensive care unit. SUMMARY Most respiratory pathogens can be transmitted by more than one route. Despite this, healthcare worker awareness of clinical syndromes associated with respiratory pathogens that require airborne precautions, combined with the use of standard precautions for all patients, and contact/droplet precautions for patients with undifferentiated febrile respiratory illness should be effective in interrupting the transmission of respiratory pathogens within the intensive care unit.