Updated

Nearly 25 years after a news magazine declared that an epidemic of genital herpes threatened to undo the sexual revolution, a new study finds an encouraging decline in the percentage of people infected with the herpes virus.

Back in 1982, a Time cover story headlined "The New Scarlet Letter" sounded an alarm that seems almost quaint now compared to concern over another sexually transmitted lifetime infection, the AIDS virus.

The new study shows a 19 percent drop since 1994 in the percentage of Americans ages 14 to 49 testing positive for herpes type 2, the most common cause of the recurring painful sores of genital herpes. The declines were especially pronounced among young people.

The findings, appearing in Wednesday's Journal of the American Medical Association, represent biological evidence of a decrease in risky sexual behavior among adolescents, said lead author Dr. Fujie Xu of the Centers for Disease Control and Prevention.

"Overall, this is good news. There is a decrease occurring among all youth, males and females, and in all racial groups," Xu said. "That's very encouraging."

But herpes is still uncomfortably common. Despite the decline, blood tests of more than 11,000 people found 11 percent of men and 23 percent of women carry the genital herpes, or type 2, virus. Among people in their 20s, the infection rate was almost 11 percent.

Ironically, the rates have dropped back to about where they were when Time ran its cover story, said study co-author Dr. Stuart Berman of the CDC.

"If it was a scarlet letter then, I don't know what you call it now and there's more HIV around," Berman said. Herpes greatly increases the chances of infection with HIV, the virus that causes AIDS.

"It's still an epidemic," said Dr. Tom Cherpes of the University of Pittsburgh School of Medicine, who was not involved with the study. "The fact that there's a trend downward should not be construed by anybody that herpes is under control."

In addition, 56 percent of men and 60 percent of women tested positive for the oral herpes virus, type 1, which is best known as the culprit behind cold sores, but can spread to the genitals through oral sex. Type 1 may be causing more genital infections in some groups, such as college students, Xu and Berman said.

Herpes can be treated with antiviral drugs, which can help prevent flare-ups and reduce the risk of spreading it to others. Condoms can help lower the risk of transmission, although they're not foolproof. Infected people are contagious even without symptoms.

The study was funded by the CDC. A previous CDC report in 1997 found a 30 percent increase in herpes infection since the late 1970s.

"This new data really reverses the trend," said study co-author Francis Lee of Emory University.

Dr. Kenneth Fife of the Indiana University School of Medicine, who was not involved in the study, noted that rates of infection are still disproportionately high among women and blacks. The study found 42 percent of blacks tested positive for herpes type 2, a decline of only 4 percent since 1994.

"Maybe we've finally gotten through to the young people that they need to change their behavior," Fife said. "We still see plenty of genital herpes. There are adolescents who are becoming infected."