The worst side effect of encephalitis is memory impairment:
> The most common and most disabling complication of herpes simplex encephalitis in our patients, and in other studies,9 10 20-24 was memory impairment, which especially affected short term memory. Occasionally remote memory is more severely affected than anterograde memory.
Since there is no proposed mechanism for how the virus may be involved, there is no way to know if acyclovir, cidofovir, or any nucleoside analog might help. These drugs only really help to stop actively replicating viruses (lytic viruses). Most of the herpesvirus life cycle is spent in "latency" where it only exists as a piece of DNA (some, like HHV6/7 may integrate into the host chromosome, others like HSV-1/HHV-1 and EBV/HHV-4 maintain their genome as a separate molecule). During this period, there are few, if any, genes made, but in some cases, those genes may be important to disease pathogenesis. The role of herpesviruses in latency-associated diseases is very complicated, and is also dependent on host genetics.
Might other herpes strains be involved? Zoster (chicken pox)? Epstein-Barr (mono)? Kaposi's Sarcoma/HHV8?