" Now, why was Newt asleep? Did she pass out from fright when she was abducted? Or do the Aliens administer some sort of paralysing agent to a potential host in much the same manner as a facehugger puts the host into a coma for implantation. It's difficult to believe that Hudson would've gone quietly or just passed out when he was abducted, as it seemed he was extremely pumped up on adrenaline. Or maybe potential hosts aren't always unconscious. It's entirely likely that a 6 year old girl would feint from fright, but a pumped up marine, even one who displays such cowardice as Hudson does, wouldn't. Since we don't see Hudson anywhere in the hive when Ripley is rescuing Newt, we don't know if he was conscious when he was coccooned or not – if indeed he wasn't killed. If there is a paralysis agent involved it is very mild, as only approximately 20 minutes passes between Newt being taken, and Ripley finding her."
From The Complete Record of Alien Encounters #2-22