Antiviral suppresses genital herpes.

The antiviral drug famciclovir, taken orally, imparts strong protection against genital herpes, scientists report in the Sept. 9 Journal of The American Medical Association.

The researchers gave the drug to 341 people with genital herpes, using three dosages. Another 114 received an inactive substance. None of the participants knew which pills were placebos. Participants had the option of quitting the study if they had at least two outbreaks of herpes while taking the pills. These people then were offered famciclovir that was clearly labeled.

Only 21 percent of the 211 famciclovir recipients who stayed throughout the 12-month study suffered a recurrence of herpes. About 7 in 10 of the people getting placebos had an outbreak.

The famciclovir recipients, taken altogether, reported only 1.0 to 1.8 outbreaks in the year. The highest dose protected best. Untreated participants who chose to stay in the study the full year averaged 5.1 recurrences. Participants getting the highest dose of the drug stayed free of outbreaks for an average of 11 months. Those getting the placebo averaged only 7 weeks before an outbreak.

Genital herpes, also called herpes simplex 2, infects roughly 22 percent of adults in the United States and between 7 and 28 percent of Europeans, depending on the country.

Unpublished findings from this study indicate that famciclovir may also work against herpes simplex 1, the virus that causes cold sores, says study coauthor Francisco Diaz-Mitoma, a clinical virologist at the Children's Hospital of Eastern Ontario in Ottawa.