Quantum effects in $QE{D}_{3+1}$ with an extra compactified dimension

We evaluate one-loop effects for $QE{D}_{3+1}$ in the presence of an extra compactified dimension, in a non-trivial vacuum for the gauge field, such that a non-vanishing magnetic flux is encircled along the extra dimension. We obtain the vacuum polarization tensor and evaluate the exact parity breaking term.