It is established in this episode that it has been six and a half months since the outbreak that caused the zombie apocalypse.
The Centers for Disease Control and Prevention are high security so it was not possible for the production to film there. Instead, the Cobb Energy Performing Arts Center doubled up as the CDC.
The episode's title is a homage to Michael Crichton's "The Andromeda Strain" which is about the development of a pathogen in a laboratory.
Frank Darabont's intention with the series was to follow the comic books but to take detours along the way. The trip to the CDC is one of the first of these.
The title of this episode comes from Dr. Edwin Jenner stating to the recording camera that it has been "194 days since wildfire has been declared".