Vacuum polarization effects during the reheating epoch

Quantum effects in the era of reheating of the universe after inflation are considered. A semiclassical approach to gravity theory is applied within Starobinsky's inflationary model with backreaction. Some subtleties associated with accounting for quantum effects in the one-loop approximation are clarified. An estimate of the contribution of vacuum polarization in the stress-energy tensor of matter fields to the cosmological particle creation due to the scalaron decay is presented.