Page 35 of Attachment E 
risk than work with the infectious virus or its nucleic acid and in most, if 
not all cases, clearly presents less risks”. 
Based on included considerations, the report ends with specific 
recommendations for containment. It recommends use of P2 (NIH 
Guidelines) or Cl (William’s Report) containment measures, in con- 
junction with an EK1 host vector system for cloning any viral genome or 
fragment thereof. In cases where the virus itself must be handled at 
higher levels of physical containment, they suggest use of the more 
stringent condition. The group endorsed certain portions of the NIH 
Guidelines dealing with animal virus vectors and recommended 
changes in others. A table is included to summarize the recommended 
containment levels for various viral vector and foreign DNA com- 
binations which range from L (Low or P2), M (Moderate or P3) to CbC (for 
“Case by Case") determination. Conditions under which vertebrate 
host-vector systems might be used are also suggested. Finally, use of 
baculoviruses and cauliflower mosaic viruses as vectors are also 
considered. 
