Condom use is associated with a reduced risk of contracting herpes simplex virus 2, according to a report based on pooled analysis of data from previous studies in the July 13 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Herpes simplex virus 2 (HSV2) typically causes genital herpes, a chronic, lifelong, viral infection. Although studies indicate that consistent condom use reduces the spread of HIV and other sexually transmitted diseases such as chlamydia and gonorrhea, the effectiveness of preventing the transmission of HSV2 through condom use is less certain, according to background information in the article.

Emily T. Martin, M.P.H., Ph.D., of Childrens Hospital Research Institute and the University of Washington, Seattle, and colleagues analyzed data from six HSV2 studies to assess the effectiveness of condom use in preventing the virus. The studies included three candidate HSV2 vaccine studies, an HSV2 drug study, an observational sexually transmitted infection (STI) incidence study and a behavioral STI intervention study. These yielded results from 5,384 HSV2negative individuals (average age 29) at baseline for a combined total of 2,040,894 followup days.

More than 66 percent of those who took part in the six studies were male, 60.4 percent were white, 94.1 percent were heterosexual and most reported no prior STIs.

A total of 415 of the individuals acquired HSV2 during followup. “Consistent condom users [used 100 percent of the time] had a 30 percent lower risk of HSV2 acquisition compared with those who never used condoms,” the authors write. “Risk of HSV2 acquisition decreased by 7 percent for every additional 25 percent of the time that condoms were used during anal or vaginal sex.” The risk of acquiring the virus increased significantly with increasing frequency of unprotected sex acts. There were no significant differences found in condom effectiveness between men and women.

“Based on findings of this large analysis using all available prospective data, condom use should continue to be recommended to both men and women for reducing the risk of HSV2 acquisition,” the authors conclude. “Although the magnitude of the protective effect was not as large as has been observed with other STIs, a 30 percent reduction in HSV2 incidence can have a substantial benefit for individuals as well as a public health impact at the population level.”

Arch Intern Med. 2009;169[13]12331240.