Valacyclovir and Acyclovir for Suppression of Shedding of Herpes Simplex Virus in the Genital Tract

Department of Medicine, University of Washington, Seattle, Washington 98122, USA. .
The Journal of Infectious Diseases (Impact Factor: 6). 11/2004; 190(8):1374-81. DOI: 10.1086/424519
Source: PubMed


Valacyclovir exhibits better oral absorption and higher, more prolonged serum concentrations than oral acyclovir. The efficacy of valacyclovir and acyclovir on genital herpes simplex virus (HSV) shedding was assessed in a double-blind, 3-period crossover trial.
Sixty-nine immunocompetent participants with genital HSV-2 received oral valacyclovir, acyclovir, and matching placebo in random order for 7-week periods. Participants provided daily genital mucosal swabs for HSV detection by viral culture and polymerase chain reaction (PCR).
HSV was detected at least once in 62 (90%) participants by culture and in 68 (98%) by PCR. During placebo, the total HSV shedding rate was 15.4% of days by culture (PCR, 40.2%); the subclinical shedding rate was 6.6% by culture (PCR, 27.1%). Both antivirals were associated with lower HSV shedding by culture (relative risk [RR], 0.03 [95% confidence interval [CI], 0.01-0.07] for valacyclovir and RR, 0.05 [95% CI, 0.03-0.10] for acyclovir) and PCR (RR, 0.18 [95% CI, 0.12-0.26] for valacyclovir and RR, 0.20 [95% CI, 0.15-0.28] for acyclovir), compared with placebo. No significant differences in frequency and quantity of HSV were detected by PCR between the valacyclovir and acyclovir arms.
Although the suppression of viral replication is not complete, valacyclovir and acyclovir are highly effective in suppressing the frequency and quantity of genital HSV shedding.

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    • "Rates of infection are even higher among women, owing to the greater efficiency of male-to-female (MTF) transmission [6, 7]. While multiple variables factor into the high prevalence rate at the population level, the fact that most sexual transmissions occur in the absence of clinically identifiable genital lesions likely plays a major role [8, 9]. While antiviral drugs have proven effective to reduce viral transmission [6, 8, 10], they are not curative. "
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