  The dynamical relaxation and scaling properties of three different variants
of the contact process in two spatial dimensions are analysed. Dynamical
contact processes capture a variety of contagious processes such as the
spreading of diseases or opinions. The universality of both local and global
two-time correlators of the particle-density and the associated linear
responses are tested through several scaling relations of the non-equilibrium
exponents and the shape of the associated scaling functions. In addition, the
dynamical scaling of two-time global correlators can be used as a tool to
improve on the determination of the location of critical points.
