Preamble The mode(s) and risk of transmission for each specific disease agent included in Appendix A were reviewed. Principle sources consulted for the development of disease-specific recommendations for Appendix A included infectious disease manuals and textbooks [833, 1043, 1044]. The published literature was searched for evidence of person-to-person transmission in healthcare and non-healthcare settings with a focus on reported outbreaks that would assist in developing recommendations for all settings where healthcare is delivered. Criteria used to assign Transmission-Based Precautions categories follow:

• A Transmission-Based Precautions category was assigned if there was strong evidence for person-to-person transmission via droplet, contact, or airborne routes in healthcare or non-healthcare settings and/or if patient factors (e.g., diapered infants, diarrhea, draining wounds) increased the risk of transmission
• Transmission-Based Precautions category assignments reflect the predominant mode(s) of transmission
• If there was no evidence for person-to-person transmission by droplet, contact or airborne routes, Standard Precautions were assigned
• If there was a low risk for person-to-person transmission and no evidence of healthcare-associated transmission, Standard Precautions were assigned
• Standard Precautions were assigned for bloodborne pathogens (e.g., hepatitis B and C viruses, human immunodeficiency virus) as per CDC recommendations for Universal Precautions issued in 1988 [780]. Subsequent experience has confirmed the efficacy of Standard Precautions to prevent exposure to infected blood and body fluid [778, 779, 866].

Additional information relevant to use of precautions was added in the comments column to assist the caregiver in decision-making. Citations were added as needed to support a change in or provide additional evidence for recommendations for a specific disease and for new infectious agents (e.g., SARS-CoV, avian influenza) that have been added to Appendix A. The reader may refer to more detailed discussion concerning modes of transmission and emerging pathogens in the background text and for MDRO control in Appendix B (Management of Multidrug-Resistant Organisms in Healthcare Settings).

Sections in Appendix A

Type and Duration of Precautions Recommended for Selected Infections and Conditions

Table 1. History of Guidelines for Isolation Precautions in Hospitals

Table 2. Clinical Syndromes or Conditions Pending Confirmation of Diagnosis Warranting Empiric Transmission Based Precautions in Addition to Standard Precautions

Table 3. Infection Control Considerations for High-Priority (CDC Category A) Diseases that May Result from Bioterrorist Attacks or are Considered to be Bioterrorist Threats

Table 4. Recommendations for Application of Standard Precautions for the Care of All Patients in All Healthcare Settings

Table 5. Components of a Protective Environment

Figure. Example of Safe Donning and Removal of Personal Protective Equipment (PPE)