  This paper establishes results on the existence and uniqueness of solutions
to McKean-Vlasov equations, also called mean-field stochastic differential
equations, in an infinite-dimensional Hilbert space setting with irregular
drift. Here, McKean-Vlasov equations with additive noise are considered where
the driving noise is cylindrical (fractional) Brownian motion. The existence
and uniqueness of weak solutions are established for drift coefficients that
are merely measurable, bounded, and continuous in the law variable. In
particular, the drift coefficient is allowed to be singular in the spatial
variable. Further, we discuss existence of a pathwisely unique strong solution
as well as Malliavin differentiability.
