This study will follow subjects that participated in the NicVAX phase III studies for a second year. These predecessor studies, Nabi-4514 (NCT#00836199) and Nabi-4515 (NCT#01102114) evaluate the efficacy and safety of 6 vaccinations of NicVAX or placebo as an aid to smoking cessation. The two phase III studies are one year in duration, and subjects who complete these studies are eligible to enroll in Nabi-4522. As the phase III studies are ongoing, subject assignment to NicVAX or placebo will remain masked. No intervention will be administered in Nabi-4522. Subjects will be followed for immunogenicity (anti-nicotine antibody level)and for safety.
