  The vacuum inflation with a boundary condition specified at a short-distance
scale in a generally primeval non-flat Universe, and implications of the
correspondingly modified primordial power spectrum via the WMAP data are
investigated. We obtain a general form of the modified primordial power
spectrum including the effects of both possibly new physics scale and the
spatial curvature. The modulation of the primordial power spectrum due to new
physics is of the order $H/\Lambda$, where $H$ is the Hubble parameter during
inflation and $\Lambda$ is the new physics scale that is key to inflation,
while the modulation from the curvature effect is of the order $K/k^2$, where
$K$ is the spatial curvature before inflation and $k$ is the comoving wave
number. We also find that a closed Universe before inflation is favored by WMAP
five-year data.
