Caroline felt dizzy at the thought of something so tiny having such devastating power.

"But the more blood samples I have, the better I can focus on the way the virus interacts with immune people versus someone who is susceptible to infection."

Erica finished collecting a sample from Lincoln and then looked them both over in concern. "You two look exhausted. How much sleep have you had?"

"Not much," Caroline said. Lincoln merely grunted.

"Why don't you ...