Prior clinical trials examined several schedules of a nicotine vaccine (NicVAX) for anti-nicotine antibody responses, and their impact on helping smokers quit. The best schedule so far has been one with doses at weeks 0, 4, 8, 16 and 26. This new study tests whether changing the schedule to weeks 0, 4, 8, 12 and 16 is an improvement for stimulating antibodies to nicotine. Routine vaccine safety information is also collected. Amendment 1 adds a 6th dose at week 26, and extends follow-up through week 52.