In this Letter, we apply time-dependent renormalization to the perturbation term in modified Redfield theory. We show the general reaction rate formula, which is numerically calculable, and discuss new findings about quantum vibrational effects with respect to the modified Redfield formalism. Using the renormalization treatment, we discuss the analytical origins of its increasing reaction rate with the present, more accurate formalism. (C) 2015 Elsevier B.V. All rights reserved.