Daily Therapy Cuts Herpes Transmission Risk
Taking Valtrex Once a Day Reduces Risk of Spreading Herpes
Dec. 31, 2003 -- People with herpes who take an antiviral drug
once a day can reduce the risk of transmitting the virus to their sexual
partners by nearly 50%.
A new study shows that daily therapy with the antiviral drug
Valtrex significantly lowers the risk of transmitting genital herpes among
heterosexual couples in which one partner is infected with the herpes simplex
virus type 2 (HSV-2).
Valtrex is commonly used to treat outbreaks of genital herpes,
but preliminary results of this study prompted the FDA to approve a second
indication for Valtrex in reducing the risk of transmitting the disease to
susceptible heterosexual partners. The complete results appear in the Jan. 1,
2004, issue of TheNew England Journal of Medicine.
Valtrex is manufactured in the U.S. by GlaxoSmithKline.
GlaxoSmithKline is a WebMD sponsor.
Daily Therapy Helps Prevent Herpes Transmission
In the study, researchers followed 1,484 heterosexual,
monogamous couples in which one partner was diagnosed with genital herpes and
was experiencing symptoms and the other partner was not. The infected partners
were randomly chosen to take either 500 mg of Valtrex or a placebo once a day
for eight months.
The couples were counseled on safer-sex practices, such as
using condoms during sexual contact and refraining from sexual contact when the
infected partner is experiencing symptoms or an outbreak of genital herpes.
Sexual transmission to a partner has been shown to occur even when the infected
partner has no symptoms.
Researchers found the risk of transmitting the HSV-2 virus from
one partner to the other was reduced by 48% in the Valtrex group, and the
incidence of symptomatic genital herpes among the partners of those using
Valtrex was reduced by 75%. (Not all people infected with the HSV-2 virus go on
to develop symptoms.)
The study also showed there was evidence of HSV-2 DNA detected
in samples of genital secretions on 2.9% of the days among infected partners
who used daily Valtrex therapy compared with 10.8% of the days of those who
received the placebo. Daily therapy also reduced the frequency of genital
herpes outbreaks among the infected partners.
Results Open Door to HIV Prevention Studies
In an editorial that accompanies the study, Clyde S.
Crumpacker, MD, of Beth Israel Deaconess Medical Center in Boston, says these
results provide the basis for future studies on whether daily therapy to
prevent HSV-2 infection might also reduce the risk of HIV transmission.
Millions could benefit if the use of acyclovir and related
drugs, such as Valtrex and Famvir, are proven to decrease the transmission of
HIV by preventing HSV-2 genital ulcers, writes Crumpacker. Acyclovir was the
first of the drugs used to treat genital herpes, but newer drugs have been
developed that can be taken fewer times during the day.
There is a clear association between the prevalence of genital
herpes infection and the explosion in heterosexual transmission of HIV, he
Crumpacker writes that generic acyclovir is the cheapest and
safest of the antiviral drugs and is unlikely to cause resistance or lose
effectiveness with prolonged use.