Severe acute respiratory syndrome and respiratory protection.

To the Editor—Severe acute respiratory syndrome (SARS) emerged last year as a new infectious disease, as well as an occupational hazard for health care workers treating infected patients. The Centers for Disease Control and Prevention (CDC) recently drafted guidlines suggesting that routes of transmission of the SARS-associated coronavirus (CoV) involve the mucous membranes, such as the respiratory system and conjunctivae of the eyes (ocular and fomite viral). Correspondence by Wong in the Journal suggests that the N-95 mask (respirator) is “appropriate” in the protection against the SARS CoV. This notion is supported by the CDC’s recommendation that N-95 respirators be worn to protect health care workers against inhalation hazards from SARS. I have recently suggested that a higher level of protection (ie a full-face air-purifying respirator; FFR) is warranted, because droplets under appropriate conditions may dry out and result in small airborne particles. Occurrence of these particles seems to be most relevant to the spread of SARS when health care workers perform aerosol-generating procedures, especially because the SARS CoV may survive outside the body for longer than 48 hours.