  We construct and study the vacuum polarization, $\langle
\phi^{2}\rangle_{D},$ of the quantized massive scalar field with a general
curvature coupling parameter in higher-dimensional static and
spherically-symmetric black hole spacetimes, with a special emphasis put on the
electrically charged Tangherlini solutions and the extremal and ultraextremal
configurations. For $4 \leq D \leq 7$ the explicit analytic expressions for the
vacuum polarization are given. For the conformally coupled fields the relation
between the trace of the stress-energy tensor and the vacuum polarization is
examined, which requires knowledge of the higher-order terms in the
Schwinger-DeWitt expansion.
