During the preparation of this Report, Dr. Owens was supported by the Department of Veterans Affairs.

We are grateful to our expert advisors for their thoughtful comments and guidance. We would like to give special thanks to Sara H. Cody, M.D., Santa Clara County Communicable Disease Officer, for her many valuable suggestions informed by her front line experiences. We thank the Stanford University research librarians who helped us design our search strategies: Rikke Greenwald (Lane Medical Library), Ann Latta (Social Sciences Resource Center), Joan Loftus (U.S. Government Documents Bibliographer) and Michael Newman (Falconer Biology Library). Finally, we extend our thanks to Cynthia Yock for her help reviewing articles, and Amy J. Markowitz, Susan Nguyen, Lyn Dupr?, and Vandana Sundaram for their careful editorial review.