How long does rabies vaccine last?

Long duration: but please check this link for the WHO position paper on the vaccine and the disease, good luck http://www.who.int/immunization/Rabies_slides_Aug_2010.pdf

Generally 2 yrs: If you complete the primary series it is expected to provide protection for 2 years from the completion date. Those working in high risk professions are encouraged to either confirm immunity with titers or have a booster at that point to expend protection.