Viremia in acute herpes zoster.

Background: A phase 2 trial was conducted to evaluate the efficacy of a topical antiviral, sorivudine, as an adjuvant to valacyclovir for the treatment of acute herpes zoster.

Methods: In this randomized, placebo-controlled, double-blind trial, 25 patients were treated with either sorivudine or placebo cream. All patients began 7 days of valacyclovir treatment on day 3. Zoster lesion swab samples and samples of peripheral blood mononuclear cells were collected periodically throughout the study and were analyzed for varicella-zoster virus (VZV) DNA by use of both qualitative and real-time polymerase chain reaction. Serum samples collected periodically throughout the study were analyzed for VZV DNA by use of real-time polymerase chain reaction.

Results: VZV DNA was detected in all 3 sample types, and the number of viral copies correlated with the progression of herpes zoster. No statistically significant differences were seen between the placebo- and sorivudine-treated groups with respect to clinical characteristics or laboratory test results.

Conclusion: The detection of VZV DNA in the serum and peripheral blood mononuclear cells of all 25 zoster patients documents that viremia is a common manifestation of herpes zoster. Sorivudine cream appears to be a safe and well-tolerated adjuvant therapy; however, further phase 2 studies are needed to determine its clinical efficacy for the treatment of herpes zoster. Trials registration. ClinicalTrials.gov identifier: NCT00652184.