Hospital-associated Middle East respiratory syndrome coronavirus infections.

To the Editor: Assiri et al. (Aug. 1 issue)1 provide valuable information about a hospital outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection. However, the authors do not describe the infection-control measures used in the hospital, and they do not discuss the possibility of aerosol transmission of MERS-CoV, a coronavirus similar to the severe acute respiratory syndrome coronavirus (SARSCoV). MERS-CoV can cause severe or fatal disease, and there is no prophylaxis or specific treatment. If the form of transmission is not understood, health care professionals should adhere to the precautionary principle that reasonable steps to reduce risk should not await scientific certainty. It is for this reason that the Centers for Disease Control and Prevention (CDC) recommended airborne precautions (the use of respirators rather than surgical masks), in addition to standard and contact precautions, for all patients with MERS-CoV. There is evidence that SARS-CoV was transmitted by respiratory aerosols,2-4 and surgical masks do not provide adequate protection against inhalation of aerosols.5 Health care workers have already been infected with MERS-CoV. It would be prudent for hospitals with the resources to do so to provide a higher level of protection (i.e., respirators) for their health care workers. Kathleen Harriman, Ph.D., M.P.H.