A six-dimensional state-to-state quantum dynamics study is carried out for the prototypical complex-formation OH + CO -> H + CO2 reaction from the ground and two vibrationally excited initial states on the Lakin-Troya-Schatz-Harding potential energy surface for the total angular momentum J = 0, using the multiple-step reactant-product decoupling method. With three heavy atoms and deep wells on the reaction path, the reaction represents a huge challenge for accurate quantum dynamics study. The effects of reagent vibrational excitation on product CO2 vibrational state distributions and product energy partition were investigated for reagents in the ground rotational state. It is found that the initial CO vibrational excitation essentially has the same effect on the product energy partition as the reagent translational excitation, while the initial OH excitation leads to slightly more internal energy in CO2. (C) 2012 Elsevier B.V. All rights reserved.