 The emergency response is complicated by a Federal budget freeze, when all "non-essential" government employees are sent home.Cornwall says in an introduction to a 2008 reprint that a decade ago the idea of a deliberate virus threat seemed fanciful and improbable, and she got more access to government facilities like the CDC for researching the book than she would have got a decade later.She said that her "modus operandi when I write a book is to ask my characters where they are and what they are doing.