http://www.mensnewsdaily.com/archive/newswire/news2005/0205/022805-oral-sex.htm

Herpes Risk Rises With Oral Sex

February 28, 2005
MND NEWSWIRE

PITTSBURGH, Feb. 28 – The first clinical study to document risk of
acquiring herpes simplex virus type 1 infection based on sexual
activity has linked oral sex and vaginal intercourse with a
demonstrably higher rate of infection, particularly in young women,
researchers from the University of Pittsburgh report in the February
issue of Sexually Transmitted Diseases, the journal of the American
Sexually Transmitted Diseases Association.

Genital herpes is one of the most common sexually transmitted
diseases in the United States. Nationwide, at least 45 million
people ages 12 and older – or one out of five adolescents and adults
– have had a genital herpes infection. Between the late 1970s and
the early 1990s, the number of Americans with genital herpes
infection increased by 30 percent, according to the U.S. Centers for
Disease Control and Prevention. While there is no cure, antiviral
medications can shorten and prevent outbreaks. Daily suppressive
therapy can reduce, but not eliminate, risk of transmission to
non-infected partners.

Medical students traditionally have been taught that herpes simplex
type 1 (HSV-1) infections most often take place above the waist,
while herpes simplex type 2 (HSV-2) predominates below the belt.
More recent evidence, however, suggests that HSV-1 also is an
important pathogen in genital herpes infections, especially in
younger women. HSV-1 is more commonly known to cause infections of
the mouth and lips, often called fever blisters or cold sores. Viral
shedding and disease transmission is possible even in the absence of
a visible outbreak.

"Receptive oral sex and vaginal intercourse were found to be
significant risk factors for the acquisition of HSV-1," said Thomas
Cherpes, M.D., an infectious diseases fellow at the University of
Pittsburgh School of Medicine and the study's first author. "Because
oral HSV-1 infections are less frequent in childhood and
adolescence, future prevention strategies will need to consider
increased susceptibility for HSV-1 among young adults, and the
important contribution of HSV-1 to the growing genital herpes
epidemic."

Researchers enrolled 1,207 non-pregnant women ages 18 to 30 at three
Pittsburgh-area health clinics between 1998 and 2000. Participants
were asked to return for three follow-up visits at four-month
intervals. At each study visit, blood samples were tested for HSV-1-
and HSV-2-specific antibodies, and surveys of sexual behavior and
demographic information were completed.

Initially, HSV-1 was found in 38 percent of women aged 20 or
younger. During the follow-up period, analysis found that women who
had vaginal intercourse had a more than six-fold higher risk of
acquiring HSV-1 than sexually inactive women, or 6.8 versus 1.2
cases. For those who had only receptive oral sex without vaginal
intercourse, however, the risk was even greater – 9.8 versus 1.2
cases.

"The low frequency of infection we detected at enrollment is
consistent with other research indicating a reduction in HSV-1
prevalence among younger people," said Sharon Hillier, Ph.D.,
professor in the departments of obstetrics, gynecology and
reproductive sciences and molecular genetics and biochemistry at the
University of Pittsburgh School of Medicine and the study's senior
author. "As a result, a significant number of young adults are now
susceptible to oral or genital HSV-1 infection."

This is important because most current research on genital herpes
vaccine development focuses on HSV-2, added Dr. Hillier, who also is
a senior investigator at the Magee-Womens Research Institute.

The falling rate of childhood HSV-1 infections is complicating the
scenario by leaving larger numbers of young people susceptible to
genital infection with HSV-1, according to Dr. Cherpes, particularly
since surveys show a high rate of participation in sexual activities
that put them at higher risk.

"Lifetime prevalence of receptive oral sex among sexually active
women is 75 percent," he said. "In our group, more than 90 percent
of study participants reported a history of such activity."

Drs. Cherpes and Hillier note that future vaccine development should
include HSV-1 targets to reduce susceptibility.