In older patients, prophylaxis of
herpesvirus infections mainly involves preventing the recurrence of herpes simplex virus (HSV) and complications of
herpes zoster in immunocompetent patients, while in immunocompromised patients it is more concerned with the prevention of opportunistic virus reactivation. HSV
ocular infection is the most frequent cause of corneal
blindness in the US. The effectiveness of
aciclovir 400mg twice daily in preventing the recurrence of HSV
eye disease in immunocompetent patients has been well demonstrated. The issue of
treatment duration for patients with highly recurrent ocular herpes remains unresolved. Post-herpetic
neuralgia (PHN) is one of the most common neuralgic illnesses worldwide. Some progress in prevention of PHN has been made with a combination of
antiviral therapy (
famciclovir or
valaciclovir), started within 72 hours of onset of the
rash, and
analgesic treatment. However, the best prevention of PHN is the prevention of
herpes zoster disease, and the
varicella vaccine is an option which over the next few years will be tested in clinical trials. For immunocompromised patients of any age, restoring immunity prevents herpesvirus disease, as demonstrated for cytomegalovirus (CMV) in
AIDS patients receiving
highly active antiretroviral therapy. Specific
antiviral therapy during the initial period after
transplantation could prevent reactivation of HSV or CMV in seropositive recipients. Whether pre-emptive
therapy or prophylaxis with
ganciclovir is the optimal approach against CMV remains controversial, and the relative merits and limitations of each approach may guide the choice. In
stem cell transplantation, pre-emptive
therapy with
foscarnet avoids the
neutropenia and related complications associated with
ganciclovir. In renal transplant recipients, universal prophylaxis of CMV
infection with
valaciclovir has the same efficacy as
ganciclovir. Although it is relatively toxic,
cidofovir should be further evaluated because of its in vitro activity against most DNA viruses.