This is a flash fiction I wrote for a contest. It had to be under 500 words, and that's really hard for me.
“I can’t believe we are going to be working in Andromeda together! On the first expedition even!”

“It’s great, Marcy,” replied her husband, barely raising his head from the papers in front of him.

“Oh you! Just because you’ve been on these missions before! Show a little enthusiasm!”

“I’m sorry, hon. I need to get through these mining reports. His face contorted as he stifled a cough.

“John! Did you cough? What’s wrong?” Marcy cried out.

“Just clearing my throat,” John answered with a small smile.

“Are you sure?”

“Positive, silly. Look, I need to get some work done. Why don’t you go out to the observation deck for awhile?”

“Well, okay, if you really are all right . . .”

Sneezing, John didn’t hear the door open. His eyes widened as he saw Marcy with the medic.

“No! I’m not sick!” he shouted as the medic injected him with enough curare to stop his heart.

“We couldn’t let him infect the Andromedans. We couldn’t risk killing a whole species again," Marcy kept repeating as they led her to the infirmary for observation. “We cured cancer, and AIDs; why can’t we cure a cold?” she asked plaintively.