Genital herpes can reactivate even during high dose antiviral therapy
Taken from The Lancet – by Bruce Sylvester – A new evaluation of data from three trials of antiviral therapy to treat genital herpes (herpes simplex virus type 2/HSV-2) indicates that the virus can reactivate in breakthrough episodes, even when doses of antiviral therapy are high. The findings were published online on Jan. 3, 2012 by The Lancet.
The investigators evaluated data from three separate but complementary open-label cross-over studies involving 113 subjects. The studies compared treatment with no medication to aciclovir 400mg twice daily (standard-dose aciclovir); valaciclovir 500mg daily (standard-dose valaciclovir) with aciclovir 800mg three times daily (high-dose aciclovir); and standard-dose valaciclovir with valaciclovir 1g three times daily (high-dose valaciclovir).
The researchers found that short episodes of subclinical (symptom free) HSV shedding continues even during treatment with standard-dose and high-dose aciclovir and valaciclovir.
Though HSV shedding fell by 50% with the highest doses of valaciclovir (1g, three times daily) compared with standard dose valaciclovir (500mg daily), the rate of breakthrough shedding episodes was unchanged, at 16–20 episodes per year.
The authors said, “Our finding that high-dose valaciclovir increases the kinetics of viral clearance, but not expansion, supports the hypothesis that these antiviral drugs do not suppress the release of virions into the genital tract.”
They added, “That we could not eliminate or even alter the frequency of shedding episodes with high-dose valaciclovir suggests that the maximum benefit of shedding reduction has probably been reached for currently available antiviral drugs.”
They concluded, “Although currently available anti-HSV therapy benefits patients by preventing clinical HSV recurrences, suppressive therapies with greater potency, including antiviral drugs or immunotherapy in the form of therapeutic vaccines, are needed to provide substantial public health benefits, such as prevention of HSV-2 transmission and HIV-1 acquisition and transmission.”