July 13 (HealthDay News) -- People who use condoms regularly can reduce their risk of getting genital herpes by 30 percent, a new study finds.
The herpes simplex virus 2 (HSV-2) causes genital herpes, which is a chronic, lifelong viral infection. Although studies have found that regular condom use reduces the spread of HIV and other sexually transmitted diseases (STDs) such as chlamydia and gonorrhea, whether they prevent the transmission of HSV-2 has been less certain, the researchers noted.
"Condoms work for herpes," said study author Emily T. Martin, a postdoctoral fellow with the Seattle Children's Hospital Research Institute.
"Even though the decrease is smaller than you would see with some other STDs, the evidence from previous studies has been unclear whether using a condom to prevent getting herpes was going to be effective, but this shows that it is," she said.
Using condoms reduces herpes transmission by only 30 percent because, unlike other STDs, herpes is transmitted by skin-to-skin contact, Martin explained.
"Transmission has a lot to do with where the virus is being shed at the time," she said. "If someone with herpes is shedding virus for an area that is not covered by a condom, we speculate the virus will spread whether or not they are using a condom."
The study is published in the July 13 issue of Archives of Internal Medicine.
For the study, Martin's team looked at data from six HSV-2 studies that dealt with the effectiveness of condoms in preventing herpes. The studies included 5,384 men and women who did not have herpes when the studies began.
During the follow-up period, which ranged from 12 to 19 months, 415 people had contracted the herpes virus. But people who used condoms 100 percent of the time reduced the risk of catching the virus by 30 percent, the researchers found.
In addition, the risk of getting herpes was reduced 7 percent "every additional 25 percent of the time that condoms were used during anal or vaginal sex," the researchers wrote.
The risk of getting herpes increased with the frequency of unprotected sex, and there was no significant difference between men and women in the effectiveness of condoms in preventing herpes transmission, they add.
Martin said using a condom not only reduces the odds of getting herpes, but of other STDs as well. "If you don't know the STD status of your partner, a condom is always a good idea," she said.
Dr. Jeffrey D. Klausner, director of STD Prevention and Control Services at the San Francisco Department of Public Health, said the study provides more evidence that condoms work.
"We know condoms can prevent the spread of sexually transmitted infections like HIV, herpes, warts, hepatitis, gonorrhea, chlamydia and syphilis, but it's always been hard to show that in research studies," Klausner said.
"If condoms can hold air and water, I never understood why folks thought they would not prevent the spread of germs, which are much, much larger than air or water molecules," he said.
Klausner said that the study provides scientific evidence that condoms work and should help in efforts to get condoms into the hands of sexually active teenagers and adults.
SOURCES: Emily T. Martin, postdoctoral fellow, M.P.H., Ph.D., Seattle Children's Hospital Research Institute; Jeffrey D. Klausner, M.D., M.P.H., director, STD Prevention and Control Services, Department of Public Health, San Francisco; July 13, 2009, Archives of Internal Medicine