IFNAR1 and herpes simplex encephalitis: Complete loss-of-function (LOF) of one of the subunits of the heterodimeric IFNAR complex has also been associated with disseminated infection from live attenuated measles, mumps, and rubella (MMR) or yellow fever vaccines (YFV) in infancy, as well as in one case with fatal Herpes simplex virus encephalitis (HSE) [165,166].