  We define a modified covariant Klein-Gordon (KG) equation containing quantum
vacuum contributions arising from the self-interaction of matter with its own
internal kinetic energy. The modified KG equation is exemplified for a variety
of vacuum fields and various properties of the equation are articulated
thereof. Generalized commutation and Energy-Momentum relations are
characterized for a null vacuum-phase scenario of the proposed vacuum field
$\lambda$. Within this limited scenario, a representation theorem is introduced
suggesting that one can equally modify the spacetime structure or momentum
operator in articulating the proposed quantum theory. Such a modified KG
equation is further shown to eliminate infrared and the ultraviolet divergences
in the generalized Klein-Gordon propagator.
