Ganciclovir
Ganciclovir has also been used with some success in treating "Human herpesvirus 6" infections.
Human herpesvirus 6
More specific to HHV-6, researchers in 2004 discovered that the initial stages of MS are associated with high levels of the active virus. Soon thereafter, researchers discovered that levels of active HHV-6 are also elevated during relapses/exacerbations of MS.